Case Reports in Pathology The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. A Case Report: Gastric Mixed Neuroendocrine-Nonneuroendocrine Neoplasm with Aggressive Neuroendocrine Component Wed, 24 May 2017 06:40:05 +0000 Mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN) is defined as mixed epithelial neoplasms composed of both neuroendocrine and nonneuroendocrine components with variable proportions for each component. Neuroendocrine component can show morphological features including well- or poorly differentiated neuroendocrine neoplasms and nonneuroendocrine component can present different tumor types depending on the site of origin. Recently, studies of tumors have shown that MiNENs are not as rare as our traditional belief, due to the wide application for immunohistochemistry. However, our knowledge of MiNENs is still limited. There is no universal consensus about nomenclature, classification, and guideline of treatment. Hereby, we would like to present a case report of gastric MiNEN with aggressive neuroendocrine component to contribute a small part towards common understanding of gastric MiNENs. Quang Duy Pham, Ichiro Mori, and Robert Y. Osamura Copyright © 2017 Quang Duy Pham et al. All rights reserved. Langerhans Cell Sarcoma: A Case Report Demonstrating Morphological and Immunophenotypical Variability within a Single Lesion Wed, 24 May 2017 06:37:24 +0000 Langerhans cells are antigen presenting dendritic cells and tumours arising from these are rare. The tumours arising from these dendritic cells are divided into two categories according to a WHO classification: Langerhans cell histiocytosis and Langerhans cell sarcoma. It is the degree of atypia and clinical aggressiveness that distinguishes the two subtypes. Langerhans cell sarcoma (LCS) is a neoplastic proliferation of Langerhans cells which can occur in skin, bone marrow, lymph nodes, spleen, liver, and lung. LCS can present with multiple cutaneous and systemic lesions. We present a case of Langerhans cell sarcoma with a unique morphological appearance and variable immunohistochemical profile within a single cutaneous lesion. LCS is a rare malignancy and its diagnosis is based on morphology, immunophenotypical examination, and ultrastructural analysis by electron microscopy. Our case highlights a unique morphological description of LCS wherein the pleomorphic neoplastic cells show epidermotropism and are surrounded by a variable amount of inflammatory infiltrate within a single cutaneous lesion. A single cutaneous lesion of Langerhans cell sarcoma with variable immunohistochemical profile has not been described so far. Rasika Singh, Charles Edward Keen, Christopher Stone, and Patrick Sarsfield Copyright © 2017 Rasika Singh et al. All rights reserved. Primary Renal Carcinoid with Bilateral Multiple Clear Cell Papillary Renal Cell Carcinomas Tue, 23 May 2017 07:48:51 +0000 Clear cell papillary renal cell carcinoma (CCPRCC) is a newly recognized entity in the 2016 WHO classification and usually presents as a small, circumscribed, solitary mass of indolent nature. CCPRCCs could seldom occur in conjunction with other synchronous or metachronous kidney tumors and even less frequently as bilateral masses. To our knowledge, multiple bilateral CCPRCCs have never been described with the existence of a synchronous well-differentiated neuroendocrine tumor of the kidney and hence reported here as a unique case. This case report highlights the importance in considering this entity and its unusual presentation in the differential diagnosis as a possible mimicker of Von Hippel-Lindau syndrome. Daniel A. Anderson and Maria S. Tretiakova Copyright © 2017 Daniel A. Anderson and Maria S. Tretiakova. All rights reserved. Benign Multicystic Peritoneal Mesothelioma: A Rare Condition in an Uncommon Gender Thu, 18 May 2017 00:00:00 +0000 Benign Multicystic Peritoneal Mesothelioma (BMPM) is a rare condition that arises from the abdominal peritoneum. Fewer than 200 cases have been reported worldwide. BMPM usually affects premenopausal women and is extremely rare in men. Many factors are suspected to contribute to its development, such as previous surgery, endometriosis, and familial Mediterranean fever. The main management is surgical resection; however, it is estimated that the recurrence rate is up to 50%. Malignant transformation is rare. We report a case series of three male patients who were diagnosed with BMPM and were treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). Muhammad S. Khurram, Hamadullah Shaikh, Uqba Khan, Jacob Edens, Warda Ibrar, Ameer Hamza, Awais Zaka, Roohi Bano, and Tarik Hadid Copyright © 2017 Muhammad S. Khurram et al. All rights reserved. Sporadic Retroperitoneal Hemangioblastoma: Report of a Case and Review of the Literature Thu, 18 May 2017 00:00:00 +0000 We report a case of sporadic isolated hemangioblastoma arising from the retroperitoneum and provide a review of the scarce literature regarding this very rare tumor. Furthermore, we thoroughly describe the pathologic features and the broad differential diagnosis that should always be included in the study of any retroperitoneal soft tissue mass to arrive at the final diagnosis. F. G. Jalikis, B. L. Hoch, R. Bakthavatsalam, and M. I. Montenovo Copyright © 2017 F. G. Jalikis et al. All rights reserved. Keratoacanthoma of the Nasal Septum Secondary to Ranibizumab Use Thu, 11 May 2017 06:24:18 +0000 Keratoacanthoma (KA) is a benign epithelial tumor that typically presents as a firm, cone-shaped, flesh-colored nodule with a central horn-filled crater. KA is considered to be a low-grade variant of squamous cell carcinoma (SCC). We report a rare case of a 72-year-old male who presented with a KA involving the nasal septum, possibly related to ranibizumab use. A flesh-colored lesion on the right anterior nasal septum lesion was visualized on examination. Histologic examination revealed a well-circumscribed, dome-shaped central crater filled with keratin, well-differentiated squamous epithelium with ground-glass cytoplasm with pushing margins, and intraepithelial microabscesses establishing the diagnosis of KA. KA of the nasal septum has only been reported once in the literature. This case is unusual because it normally presents on sun-exposed areas. Additionally, this patient was taking ranibizumab, a vascular endothelial growth factor (VEGF) inhibitor for macular degeneration. Despite ranibizumab not being directly linked to precancerous and cancerous skin lesions, agents in this medication class have been. Although it is difficult to prove associations in this isolated case, the role of ranibizumab causing cutaneous lesions should be further investigated. Jason E. Cohn, Hilary M. Caruso Sales, Giang Huong Nguyen, Harvey Spector, and Kenneth Briskin Copyright © 2017 Jason E. Cohn et al. All rights reserved. Hybrid Desmoplastic/Follicular Ameloblastoma of the Mandible: A Case Report and Review of the Literature Thu, 11 May 2017 00:00:00 +0000 Desmoplastic ameloblastoma (DA) is one of the 6 histopathological subtypes of ameloblastoma. Hybrid lesions in which histopathologically conventional ameloblastoma coexists with areas of DA are rare. A 40-year-old male was referred to our hospital complaining of a swelling in the right premolar region of the mandible. A panoramic radiograph showed an area of radiolucency with a well-defined corticated border, whereas computed tomography revealed a unilocular radiolucent lesion and buccal expansion together with cortical perforation. The lesion was treated via enucleation and curettage of the marginal bone and fenestration. A histopathological examination showed a hybrid ameloblastoma with a pronounced desmoplastic pattern and follicular changes. The patient’s postoperative course has been favorable up to now, and no marked changes have been observed. We presented a case of hybrid ameloblastoma and reviewed the 36 reported cases of hybrid ameloblastoma that have been reported in the English literature. Masayasu Iwase, Airi Fukuoka, Yoko Tanaka, Naoyuki Saida, Eriko Onaka, Sanae Bando, and Gen Kondo Copyright © 2017 Masayasu Iwase et al. All rights reserved. Strongyloides Colitis as a Harmful Mimicker of Inflammatory Bowel Disease Sun, 07 May 2017 07:05:51 +0000 Autoinfection caused by Strongyloides stercoralis frequently becomes a life-long disease unless it is effectively treated. There is overlapping histomorphology between Strongyloides colitis and inflammatory bowel disease; a low index of suspicion can lead to misdiagnosis and fatal consequences. We present a case of Strongyloides colitis mimicking the clinical and pathologic features of inflammatory bowel disease. A 64-year-old female presented to the emergency department with a four-day history of abdominal pain, diarrhea, and hematochezia. Colonoscopy revealed diffuse inflammation suggestive of inflammatory bowel disease, which led to initiation of 5-aminosalicylic acid and intravenous methylprednisolone. Biopsies of the colon revealed increased lymphoplasmacytic infiltrate of the lamina propria with eosinophilic microabscesses and presence of larvae, consistent with Strongyloides stercoralis. Immunosuppressive medication was halted. The patient ultimately died a few days later. This case emphasizes the importance of identifying the overlapping clinical and pathologic features of Strongyloides colitis and inflammatory bowel disease. A high index of suspicion and recognition of particular histological findings, including eosinophilic microabscesses, aid in the correct diagnosis. Definitive diagnosis is crucial as each disease carries distinct therapeutic implications and outcome. Julio Poveda, Farah El-Sharkawy, Leopoldo R. Arosemena, Monica T. Garcia-Buitrago, and Claudia P. Rojas Copyright © 2017 Julio Poveda et al. All rights reserved. Diffuse Alveolar Hemorrhage in Systemic Lupus Erythematosus: Histopathologic Features and Clinical Correlations Thu, 27 Apr 2017 07:56:18 +0000 The case of a 16-year-old African-American girl with systemic lupus erythematosus, who developed diffuse alveolar hemorrhage with fatal consequences, is described. Diffuse alveolar hemorrhage is a rare but serious complication of systemic lupus. It occurs in three distinct but overlapping phenotypes, acute capillaritis, bland pulmonary hemorrhage, and diffuse alveolar damage, each of which is associated with a different group of underlying conditions. Diffuse alveolar hemorrhage is a medical emergency: choice of treatment depends on early diagnosis and determination of the underlying etiology. Acute infection, superimposed on diffuse alveolar hemorrhage in the setting of immune compromise, is often a terminal event, as in this case. Robert Ta, Romulo Celli, and A. Brian West Copyright © 2017 Robert Ta et al. All rights reserved. Primary Villoglandular Mucinous Adenocarcinoma of the Vulva Wed, 19 Apr 2017 00:00:00 +0000 Primary villoglandular mucinous adenocarcinoma of the vulva is rare tumor. We report a case of 68-year-old woman who developed this very uncommon malignant tumor. Immunohistochemical examination of this tumor revealed positive staining for Cytokeratin 20, Mucin 2, and CDX2, although Cytokeratin 7 and Mucin 6 were negative. This positive staining indicated the tumor enteric type characters. In order to exclude the possibility of the metastasis from another site, we thoroughly evaluated clinical data and extensively investigated the whole body. However, we could not detect any other tumors. The patient was treated by tumor resection. The patient remains free of disease 5 years after surgery. Akiko Matsuzaki, Masanao Saio, Noritake Kosuge, Hajime Aoyama, Tomoko Tamaki, Hirofumi Matsumoto, and Naoki Yoshimi Copyright © 2017 Akiko Matsuzaki et al. All rights reserved. Plasmacytoma as a Mimicker of Colonic Carcinoma in an Elderly Man Wed, 19 Apr 2017 00:00:00 +0000 Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells. Although it is usually restricted to the bone marrow, extraskeletal spread in the form of localised extramedullary collections of malignant plasma cells (plasmacytomas) can occur. However, gastrointestinal tract involvement in multiple myeloma is rare and overt gastrointestinal bleeding from plasmacytoma is uncommon. We report a case of colonic plasmacytoma which presented with bleeding per rectum and was initially misdiagnosed as colonic neuroendocrine carcinoma. Later the patient presented with recurrence of the colonic mass along with multiple lytic bone lesions. The diagnosis of colonic plasmacytoma with progression into multiple myeloma was given. We also discuss here the diagnostic difficulty of plasma cell neoplasms in small biopsies of the colon. Sara Mathew George, Eman Ali Aljufairi, Nisha Chandran, and Sayed Ali Isa Almahari Copyright © 2017 Sara Mathew George et al. All rights reserved. Prostate Cancer Presenting as Huge Mediastinal and Retroperitoneal Masses: Case Report and Review of the Literature Thu, 30 Mar 2017 08:11:59 +0000 Mediastinum and retroperitoneum are exceedingly rare sites for metastatic prostate cancer to occur. Here, we present the case of a 67-year-old male patient with incidental findings of mediastinal and retroperitoneal masses which were found to be due to metastatic prostate adenocarcinoma based on histopathology and immunohistochemical studies and later on supported by the significantly elevated Prostate Specific Antigen (PSA) levels. Prostate cancer should always be considered in the differential diagnosis of elderly men presenting with metastatic epithelial tumors even in unusual sites. Safa Alshaikh and Zainab Harb Copyright © 2017 Safa Alshaikh and Zainab Harb. All rights reserved. Borderline Clear Cell Adenofibroma of the Ovary Thu, 30 Mar 2017 07:56:01 +0000 Borderline clear cell tumors are extremely rare, and few cases have been reported in the literature. Herein, we present a case of borderline clear cell adenofibroma of the ovary in a 58-year-old woman who presented with a pelvic mass and constipation. Physical examination revealed a 10 cm solid midline pelvic mass. Computed tomography showed an 8 cm heterogeneous enhancing mass attached to the left posterolateral wall of the uterus. The patient’s serum CA 125 levels were slightly elevated (80.9 U/ml). The patient was given a total abdominal hysterectomy with bilateral salpingooophorectomy. On gross examination, it was found that the left ovarian tumor was an 8.0 7.5 8.0 cm solid multilobulated mass containing tiny cysts. Histologically, the tumor was composed of small glands in dense fibrous and myxoid stroma. The glands were lined with cuboidal cells with clear cytoplasm and mild to moderate nuclear atypia. No stromal invasion was observed. The pathological diagnosis was borderline clear cell adenofibroma of the left ovary. There was no reoccurrence 36 months post operation. Pilaiwan Kleebkaow, Apiwat Aue-aungkul, Amornrat Temtanakitpaisan, and Chumnan Kietpeerakool Copyright © 2017 Pilaiwan Kleebkaow et al. All rights reserved. Microcystic/Reticular Schwannoma of the Frontal Lobe: An Unusual Occurrence Mon, 27 Mar 2017 00:00:00 +0000 Schwannoma is a benign peripheral nerve sheath tumor that typically involves cranial nerves of the head and neck region. Intraparenchymal occurrence of this tumor is uncommon. Even rarer in this site is the microcystic/reticular pattern of schwannoma. This histologic variant, first described in 2008, has a predilection for visceral organs. Herein, we report the first case of microcystic/reticular schwannoma of the frontal lobe. Lauren Pearson, Erinc Akture, Julien Wonderlick, Gregory Fuller, and Maryam Zenali Copyright © 2017 Lauren Pearson et al. All rights reserved. Odontogenic Cyst with Verrucous Proliferation Exhibiting Melanin Pigmentation Mon, 20 Mar 2017 07:36:35 +0000 Verrucous proliferation arising from odontogenic cysts is a rare entity. We report an unusual case of an infected odontogenic cyst with verrucous proliferation and melanin pigmentation in a 13-year-old male patient who presented with an intraoral swelling in relation to impacted teeth 26 and 27. The enucleated lesion was diagnosed as an odontogenic keratocyst and the patient died within two years of presentation due to multiple recurrences. The clinical, radiological, and microscopic features of the lesion are presented with an attempt to discuss the etiopathogenesis. The case hereby reported is uncommon with only eight cases reported in the literature. Nidhi Manaktala, Karen Boaz, Krupa Mehta Soni, Srikant Natarajan, Junaid Ahmed, Keshava Bhat, Nandita Kottieth Pallam, and Amitha Juanita Lewis Copyright © 2017 Nidhi Manaktala et al. All rights reserved. On a Rare Cutaneous Metastasis from a Sacrococcygeal Chordoma Sun, 19 Mar 2017 06:46:19 +0000 Chordomas are rare malignant tumors of notochordal origin and are rare locally aggressive ones with a metastatic potential. The skin rarely is seen as metastatic site. We describe a case of an adult woman with cutaneous metastasis of a primary sacral chordoma excised ten years before, which appeared as a painless cutaneous mass located in the dorsal region. Once removed, the surgical specimen was formalin fixed and in paraffin embedded. Sections were stained with haematoxylin-eosin, and histochemical and immunohistochemical investigations were performed. Histologically, the neoplasia was characterized by cords or single tumor cells with an abundant myxoid stroma, conspicuous pale vacuolated cytoplasm (the classic “physaliphorous cells”), and mild nuclear atypia. Mitotic activity was scanty. At immunohistochemistry, the tumor cells were diffusely positive for S-100 protein, pan-keratins, EMA, and vimentin. A diagnosis of cutaneous metastasis of chordoma was performed. This case illustrates a diagnostic challenge because of the unusual presentation of an already rare tumor. Alessandro D’Amuri, Matteo Brunelli, Federica Floccari, Francesco De Caro, Giuliana Crisman, Francesca Sanguedolce, and Marcello Filotico Copyright © 2017 Alessandro D’Amuri et al. All rights reserved. Paravertebral Well-Differentiated Liposarcoma with Low-Grade Osteosarcomatous Component: Case Report with 11-Year Follow-Up, Radiological, Pathological, and Genetic Data, and Literature Review Thu, 09 Mar 2017 00:00:00 +0000 Despite being one of the most frequent soft-tissue sarcomas, well-differentiated liposarcoma has never been reported near the spine. The authors present the case of a 67-year-old man with progressive history of back pain. Physical examination revealed a mass located within the right paravertebral muscles. MR and CT imaging showed a heavily ossified central mass surrounded by a peripheral fatty component. No connection with the underlying bone was detected on imagery and during surgery. After surgical resection, histopathological examination revealed a tumor harboring combined features of well-differentiated liposarcoma and low-grade osteosarcoma. Tumor cells displayed overexpression of MDM2, CDK4, and P16 by immunohistochemistry and CGH revealed amplification of 12q13-15 as the only genetic imbalance. MDM2 FISH analysis was performed but was inconclusive. The pathological, immunohistochemical, and genetic features, the differential diagnoses, and the therapeutic management of this unusual tumor are discussed. No complementary treatment was performed initially. Following first treatment, two recurrences occurred 6 and 9 years later, both displaying histological features similar to the first occurrence. Radiotherapy was started after the second recurrence. Follow-up shows no evidence of disease 11 years after initial diagnosis. This case was unusual due to the paravertebral location of the tumor and its divergent differentiation. Nicolas Macagno, Stéphane Fuentes, Gonzague de Pinieux, André Maues de Paula, Sébastien Salas, Jean-Camille Mattéi, Charlotte Dupuis, Romain Appay, Alain Aurias, Henry Dufour, Dominique Figarella-Branger, and Corinne Bouvier Copyright © 2017 Nicolas Macagno et al. All rights reserved. Adenoid Cystic Carcinoma of the Uterine Cervix: A Report of 2 Cases Tue, 28 Feb 2017 00:00:00 +0000 Adenoid cystic carcinoma is malignant tumor that exceptionally occurs in the uterine cervix. It is mostly seen in postmenopausal women and has an aggressive clinical course. We report two cases of an adenoid cystic carcinoma associated with a high grade squamous intraepithelial lesion and invasive squamous cell carcinoma of the uterine cervix and discuss briefly its clinical and pathological characteristics. Meryem Rais, Jinane Kharmoum, Soumaya Ech-Charif, and Basma El Khannoussi Copyright © 2017 Meryem Rais et al. All rights reserved. Revisiting Cementoblastoma with a Rare Case Presentation Sun, 26 Feb 2017 07:37:55 +0000 Cementoblastoma is a rare benign odontogenic neoplasm which is characterized by the proliferation of cellular cementum. Diagnosis of cementoblastoma is challenging because of its protracted clinical, radiographic features, and bland histological appearance; most often cementoblastoma is often confused with other cementum and bone originated lesions. The aim of this article is to overview/revisit, approach the diagnosis of cementoblastoma, and also present a unique radiographic appearance of a cementoblastoma lesion associated with an impacted tooth. Vijayanirmala Subramani, Malathi Narasimhan, Suganya Ramalingam, Soumya Anandan, and Subhashini Ranganathan Copyright © 2017 Vijayanirmala Subramani et al. All rights reserved. An Unusual Clinical Presentation of Solitary Fibrous Tumor in the Oral Cavity Thu, 23 Feb 2017 07:12:13 +0000 Solitary fibrous tumor is a rare neoplasm of mesenchymal origin that usually affects the pleura. This rarity becomes more relevant in the oral cavity since the clinical features are nonspecific. A 66-year-old female patient presented with a 3-month history of a swelling in the floor of the mouth, measuring 2 cm in greatest diameter, and pain symptomatology. Occlusal and panoramic radiographs showed no bone involvement. Ultrasonography of the submandibular and parotid salivary glands revealed normal morphology, dimensions, and echogenicity. During this exam, a nodular image of low echogenicity measuring about 2.7 × 1.8 cm was detected. An excisional biopsy was performed and histopathological analysis revealed a well-defined tumor-like lesion with alternation between hypercellular areas without a defined pattern and hypocellular areas. On immunohistochemistry, the tumor was positive for CD34 and CD99 and negative for α-SMA, S-100, and bcl-2. Combining the histopathological and immunohistochemical features, the diagnosis was solitary fibrous tumor. The patient is under periodical clinical follow-up and shows no signs of recurrence 7 months after surgical excision of the tumor. The combination of clinical-pathological and immunohistochemical features is necessary for the diagnosis. Everton Freitas de Morais, Deborah Gondim Lambert Moreira, Viviane Alves De Oliveira, Rodrigo Rodrigues Rodrigues, Adriano Rocha Germano, and Roseana de Almeida Freitas Copyright © 2017 Everton Freitas de Morais et al. All rights reserved. Urachal Tumor: A Case Report of an Extremely Rare Carcinoma Wed, 22 Feb 2017 00:00:00 +0000 The urachus is a tubular structure that connects the bladder to the allantois in the embryonic development, involuting after the third trimester. The urachus carcinoma is an extremely rare tumor that accounts for <1% of all bladder cancers. We report a case of a 46-year-old woman, with no past medical history, complaining of hematuria with 6-month duration and a physical exam and an abdominal computed topographic scan revealing an exophytic mass of 6.8 cm longer axis that grew depending on the anterior bladder wall, invading the anterior abdominal wall. Cystoscopy detected mucosal erosion. The biopsy showed structures of adenocarcinoma of enteric type. The surgical specimen showed urachus adenocarcinoma of enteric type with stage IVA in the Sheldon system and stage III in the Mayo system. This case has a 3-year follow-up without disease recurrence. José Palla Garcia, Rita Sampaio, and Carlos Peixoto Copyright © 2017 José Palla Garcia et al. All rights reserved. Retiform Sertoli-Leydig Cell Tumor in a 38-Year-Old Woman: A Case Report, Retrospective Review, and Review of Current Literature Mon, 20 Feb 2017 00:00:00 +0000 Ovarian sex cord-stromal tumors arise from the stromal cells that surround and support the oocytes. Sertoli-Leydig cell tumors belong to this category of ovarian neoplasms. We present the case of a 38-year-old woman who was found to have a right ovarian mass. The mass was resected and diagnosed as Stage I Sertoli-Leydig cell tumor, retiform variant, following histopathologic and immunohistochemical examination. This case is unusual given the rarity of the retiform variant of Sertoli-Leydig cell tumor and the atypically older age of 38 years at presentation. Laura C. Nwogu, Josh A. Showalter, Suvra Roy, Michael T. Deavers, and Bihong Zhao Copyright © 2017 Laura C. Nwogu et al. All rights reserved. Primary Hepatic Neuroendocrine Tumor with Unusual Thyroid Follicular-Like Morphologic Characteristics Mon, 20 Feb 2017 00:00:00 +0000 We describe a primary hepatic neuroendocrine tumor of a 57-year-old Thai woman who presented in 2004 with a suspicious mass in the left hepatic lobe. She underwent left hepatectomy for the 10.5-cm mass, called intermediate grade neuroendocrine carcinoma of unknown origin, likely metastatic. The tumor recurred in 2007, then called recurrent primary hepatic neuroendocrine tumor (PHNET), and the patient underwent liver transplant. Because of similarity between the neuroendocrine tumor and a thyroid tumor—specifically, follicular-like characteristics—immunohistochemical stains for thyroglobulin, TTF1, and calcitonin were performed. However, all were negative. All imaging studies revealed no evidence of a primary lesion other than the liver mass. In 2008, the patient’s liver transplant failed because of ischemic cholangiopathy, and she underwent a second liver transplant. Seven years later, in 2015, she presented with metastatic neuroendocrine tumor of intermediate grade to the lung, consistent with metastatic PHNET. She underwent left upper-lobe wedge resection to remove the tumor. The patient is alive with no evidence of disease at 13 years after initial diagnosis. This rare variant of PHNET had thyroid-like morphologic characteristics but there is no evidence of primary thyroid tumor or thyroid markers in the primary and recurrent hepatic tumors and lung metastasis. Mohd Elmugtaba Ibrahim, Kerolos Abadeer, Qihui (Jim) Zhai, and Aziza Nassar Copyright © 2017 Mohd Elmugtaba Ibrahim et al. All rights reserved. Endocrine Mucin-Producing Sweat Gland Carcinoma, a Histological Challenge Sun, 19 Feb 2017 00:00:00 +0000 Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare adnexal tumor of the skin with low-grade cytological features and neuroendocrine differentiation. It has a predilection for the skin of the eyelid, but has also been reported in the face and rarely extra-facial locations. The tumor is seen more frequently in women and on average affects the elderly. It is histologically and immunohistochemically analogous to solid papillary carcinoma of the breast/endocrine ductal carcinoma in situ with a nodular, solid, papillary, and/or cribriforming architecture, neuroendocrine differentiation, and mucin production. Since it was first described by Flieder et al. in 1997, less than 60 cases have been reported in literature. We describe the morphological and immunohistochemical features of another case with a review of the common histological differential diagnoses and emphasize the salient features that help distinguish this rare neoplasm. Mary Anne Brett, Samih Salama, Gabriella Gohla, and Salem Alowami Copyright © 2017 Mary Anne Brett et al. All rights reserved. Synchronous Seminoma in Abdominopelvic and Inguinal Testes: A Rare Presentation with Unusual Morphology Tue, 14 Feb 2017 13:37:22 +0000 The development of testes occurs in the abdomen during fetal life, after which they migrate into the scrotal sacs during the third trimester. During their descent, they may get arrested anywhere along the tract. Risk of testicular cancer is higher in patients with undescended testes, abdominal testis being more prone than inguinal. Seminoma is the commonest cancer in undescended testis. However, synchronous seminoma involving bilateral cryptorchid testis is rare. Present case is uncommon due to synchronous involvement of abdominopelvic and inguinal testes in extended age. It also exhibited unusual morphology with marked heterogeneity grossly as well as microscopically, instead of a common homogenous appearance. Neha Prabhakar, Bhawna Sethi, Seema Nagger, and Arun Saxena Copyright © 2017 Neha Prabhakar et al. All rights reserved. Lipomatous/Extensively Vacuolated Ependymoma with Signet-Ring Cell-Like Appearance: Analysis of a Case with Extensive Literature Review Tue, 14 Feb 2017 06:09:56 +0000 “Lipomatous” and “extensively vacuolated” are descriptive captions that have been used to portray a curious subset of ependymomas distinctively bearing cells with a large vacuole pushing the nucleus to the periphery and, thus, simulating a signet-ring cell appearance. Here, we would like to report the first ependymoma of this kind in a Latin American institution. A 16-year-old boy experienced cephalea during three months. Magnetic resonance imaging scans showed a left paraventricular tumour which corresponded to anaplastic ependymoma. Intriguingly, it was also composed of cells with single or multiple hollow cytoplasmic vacuoles sometimes giving a signet-ring cell-like configuration. Immunolabeling of these showed membrane positivity for GFAP, PS100, and CD99, while Ki-67 expression was null. Ultrastructural examination of retrieved paraffin-embedded tissue showed the presence of scarce microlumina filled with microvilli but failed to demonstrate any content in such optically empty vacuoles as only scant granulofibrillary debris was observed. A schism prevails at present regarding these unusual morphological variants, being either “lipomatous” or “vacuolated” based mainly on the EMA immunoprofile. This, however, is a misappropriate approaching. Could it be that perhaps we are dealing with the same histopathological entity or it may simply happen that fixation and artefacts cannot allow for their proper identification? Miguel Fdo. Salazar, Martha Lilia Tena-Suck, Alma Ortiz-Plata, Citlaltepetl Salinas-Lara, and Daniel Rembao-Bojórquez Copyright © 2017 Miguel Fdo. Salazar et al. All rights reserved. Primary Clear Cell Microcystic Adenoma of the Sinonasal Cavity: Pathological or Fortuitous Association? Sun, 05 Feb 2017 07:44:29 +0000 Primary clear cell microcystic adenoma of the sinonasal cavity is rare. It has previously been described only as a VHL-associated tumour. Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome characterised by an elevated risk of neoplasia including clear cell renal cell carcinoma (ccRCC), haemangioblastoma, and phaeochromocytoma. We describe the second reported case of a primary clear cell microcystic adenoma of the sinonasal cavity. The 39-year-old patient with VHL syndrome had previously undergone resection and ablation of ccRCC. He presented with epistaxis. Imaging demonstrated a mass in the ethmoid sinus. Initial clinical suspicion was of metastatic ccRCC. However, tumour morphology and immunoprofile were distinct from the previous ccRCC and supported a diagnosis of primary microcystic adenoma. Analysis of DNA extracted from sinonasal tumour tissue did not show loss of the wild-type allele at the VHL locus. Although this did not support tumour association with VHL disease, it was not possible to look for a loss-of-function mutation. The association of primary microcystic adenoma of the sinonasal cavity with VHL disease remains speculative. These lesions are benign but are likely to require regular surveillance. Such tumours may require repeated surgical excision. Rosalin Cooper, Hannah Markham, Jeffery Theaker, Adrian Bateman, David Bunyan, Matthew Sommerlad, Gillian Crawford, and Diana Eccles Copyright © 2017 Rosalin Cooper et al. All rights reserved. Plasmacytoid Urothelial Carcinoma of the Urinary Bladder Metastatic to the Duodenum: A Case Report—Diagnostic Relevance of GATA3 Immunohistochemistry Tue, 31 Jan 2017 09:12:02 +0000 Plasmacytoid urothelial carcinoma (PUC) of the urinary bladder is a rare and aggressive subtype of urothelial carcinoma. Its deceptive morphology is characterized by a discohesive growth of cells with plasmacytoid morphology. Since this tumor might be confused with plasmacytoma, lymphoma, or carcinoma variants, appropriate diagnosis in small biopsy samples could be challenging. This study reports the case of a 53-year-old man who presented with frequent nocturnal urgency, without hematuria. A transurethral bladder and a prostate resection specimen displayed infiltration of neoplastic cells in a spray-like discohesive pattern with occasional formation of small irregular nests and cord-like arrangements. The basic morphology of the tumor cells was plasmacytoid, with eccentric nuclei and eosinophilic cytoplasm. Tumor cells grew through the lamina muscularis mucosae, with splintering of the bladder wall musculature and infiltration of prostatic tissue. They displayed strong and diffuse nuclear reactivity for p53 and GATA3. Eight months after surgery, the patient experienced upper abdominal discomfort. A duodenal biopsy showed infiltration of plasmacytoid atypical cells strongly immunoreactive for GATA3, consistent with the previously diagnosed PUC. The patient died eleven months after the primary diagnosis of his PUC of tumor cachexia losing about 50% of his original body weight, furthermore, with ascites and intraperitoneal tumor spread. Hermann Brustmann Copyright © 2017 Hermann Brustmann. All rights reserved. Myxoid Plexiform Fibrohistiocytic Tumor Masquerading as Ganglion Cyst: A Case Report and Literature Review Tue, 31 Jan 2017 00:00:00 +0000 Background. Plexiform fibrohistiocytic tumor is a distinctive mesenchymal neoplasm of low-grade malignancy, with the capacity for biphasic differentiation toward a fibroblastic or histiocyte-like morphology. Clinically, these lesions affect different areas of the body and appear as painless, slowly growing, dermal or subcutaneous masses. To date, only three cases of myxoid variant have been reported in the English literature. Case Presentation. A 45-year-old female patient presented with a subcutaneous nodule in the right popliteal fossa. The initial impression was a benign ganglion cyst. The soft tissue tumor has been treated by local excision. The histopathological and the immunohistochemical findings supported the diagnosis of myxoid plexiform fibrohistiocytic tumor. The postoperative course was uneventful, and the patient received regular follow-up examination. She is alive without any recurrence. Conclusions. This case demonstrates how to distinguish this distinctive plexiform fibrohistiocytic tumor from other problematic soft tissue tumors. It is also remarkable for its rarely reported extensive myxoid change. Currently, there is no clear-cut correlation between the clinicopathologic findings and the behavior of this unusual variant. Chih-Yi Liu, Jui Lan, and Hsuan-Ying Huang Copyright © 2017 Chih-Yi Liu et al. All rights reserved. Newly Diagnosed Colonic Adenocarcinoma: The Presenting Sign in a Young Woman with Undiagnosed Crohn’s Disease in the Absence of Primary Sclerosing Cholangitis and a Normal Microsatellite Instability Profile Tue, 31 Jan 2017 00:00:00 +0000 Ulcerative colitis has long been linked with an increased risk for colonic adenocarcinoma, whereas Crohn’s disease (CD) has recently been reported to pose a similar increased risk. We report a 33-year-old healthy female with no family history who presented with abdominal pain and a colon mass. Histopathology revealed a moderately differentiated adenocarcinoma extending through the muscularis propria with metastatic lymph nodes and intact mismatch repair proteins by immunohistochemical expression and gene sequencing. The nonneoplastic grossly uninvolved background mucosa showed marked crypt distortion, crypt abscesses, CD-like lymphoid hyperplasia, transmural inflammation, and reactive epithelial atypia. Additional patient questioning revealed frequent loose stools since she was a teenager leading to diagnosis of a previously undiagnosed CD without primary sclerosing cholangitis (PSC). The adenocarcinoma is suspected to be related to the underlying CD. Newly diagnosed adenocarcinoma in a young female as the presenting sign for CD in the absence of PSC is extremely rare. Brett Matthew Lowenthal and Ann M. Ponsford Tipps Copyright © 2017 Brett Matthew Lowenthal and Ann M. Ponsford Tipps. All rights reserved.