Giant Parotid Pleomorphic Adenoma with Atypical Histological Presentation and Long-Term Recurrence-Free Follow-Up after Surgery: A Case Report and Review of the Literature
Table 1
Review of giant parotid pleomorphic adenoma case reports and their demographic, clinical, radiographic, surgical, and histological findings.
Large mass in the submandibular and laterocervical regions, extending intraorally from soft-palate to floor of mouth
MRI showed a mass involving the deep lobe of the parotid gland, extending into parapharyngeal, prestyloid, and submandibular spaces, displacing external and internal carotid arteries and thinning the ramus of mandible. Measuring . FNAC was indicative of PA
Deep lobe parotidectomy through cervical transparotid approach
Large, lobulated mass in the submandibular, preauricular, and laterocervical regions, extending intraorally to the lateral pharyngeal wall at the level of tongue
MRI showed a well-defined mass involving both superficial and deep lobes of the parotid gland, and extending into the parapharyngeal space, displacing tissues deep to the tonsil
Total parotidectomy through cervical transparotid approach
Large, pedunculated preauricular mass extending up to the submandibular region, with a history of rapid growth in preceding 3 months and 2 areas of ulceration with yellowish, foul-smelling discharge in the lower part of the mass. An associated anterior chest wall mass measuring was clinically identified
CT showed a mass with multiple encapsulated nodules involving the entire parotid gland, having several feeder vessels and supplied predominantly by the transverse facial artery. Coincidental finding of abnormal skull base lesion measuring 4 cm in diameter. Chest radiograph revealed multiple metastatic nodules, measuring around 1 cm, in both lungs
Total parotidectomy + simultaneous resection of anterior chest wall mass
exophytic tumor (6.051 kg)
Sudden increase in size with ulceration and discharge
Pleomorphic adenoma with focal areas of malignant adenocarcinoma cells with hyperchromatic nuclei and increased mitotic figures. Similar histological findings observed in the resected anterior chest wall mass
Patient died 6 months postsurgery, due to metastatic lung disease
Solid mass in preauricular and mandibular angle regions
MRI showed a multilobulated mass measuring 8 cm in diameter and extending from deep lobe of the parotid gland into parapharyngeal space, displacing the pharyngeal airway medially and the jugular and carotid vessels posteriorly. FNAC was indicative of PA
Total parotidectomy through cervical transparotid approach and facial nerve preservation
Pleomorphic adenoma
Postoperative facial nerve deficit which recovered completely in 6 months
Intraoral mass occupying the entire soft palate with no other associated symptoms
MRI showed a well-defined mass lesion measuring in the parapharyngeal space and with apparent continuity to the deep lobe of the parotid gland. FNAC was indicative of PA
Surgical excision of tumor mass only, through intraoral approach and “Double-Y” incision in soft palate
USG showed two hypoechogenic, lobulated masses measuring in the deep lobe of the parotid gland and posterior to mandibular ramus. MRI revealed expansive mass measuring about 5 cm in the deep lobe of the parotid gland, extending from mandibular angle to lateral pharyngeal wall medially
Using cervical transparotid approach, superficial and deep lobe parotidectomy performed separately to preserve facial nerve branches
Pleomorphic adenoma
Transient neurological deficit of marginal mandibular branch of facial nerve
MRI showed a mass in the deep lobe of the parotid gland, extending into parapharyngeal space and displacing the pharyngeal muscles medially. FNAC was indicative of PA
Using cervical transparotid approach, superficial and deep lobe parotidectomy performed separately to preserve facial nerve branches
No extraoral swelling. Intraoral mass lateral to the soft palate and displacing it across the midline
MRI showed inhomogeneous, expansive mass arising from the deep lobe of the parotid gland and measuring in the lateral pharyngeal space. The mass was seen displacing the pterygoid and pharyngeal muscles medially. FNAC was indicative of PA
Separate superficial and deep lobe parotidectomy through transcervical, mandibular split approach to preserve facial nerve branches
Pain while swallowing and sensation of foreign body in the throat since 5 months
Pleomorphic adenoma with a nucleus of carcinoma ex-PA
Large, multinodular preauricular mass extending to the submandibular region and crossing the midline. Focal areas of ulceration in the lower part of the mass
Subcutaneous parotid mass with ipsilateral cervical lymphadenopathy involving multiple nodes. Associated with severe pain and rapid increase in size. Clinically staged as stage Iva malignant disease
Only clinical examination
Total parotidectomy with comprehensive neck dissection
Nonencapsulated tumor measuring about 3.5 cm
Severe pain and rapid increase in size
Malignant epithelial cells in a chondromyxoid stroma indicative of carcinoma ex-PA. Malignant foci included high-grade squamous cell carcinoma and adenocarcinoma. One of the cervical lymph nodes showed evidence of metastatic carcinoma. Immunohistochemistry identified a melanoma component
Two months postsurgery, the patient reported severe pelvic pain, diagnosed as metastatic bone disease through MRI
Patient died 3 months postsurgery due to metastatic disease
Large mass arising from the lateral pharyngeal wall, displacing the soft palate and uvula, and narrowing the pharyngeal airway. Associated symptoms of painful swallowing, heavy snoring, and sleep apnea for past 1 year
MRI showed a circumscribed mass lesion extending from the deep lobe of the parotid gland into the parapharyngeal space with fluid spaces and septation. CT angiogram while showing splayed internal and external carotid arteries, ruled out any abnormal vascularity. Transoral FNAC was indicative of PA
Deep lobe parotidectomy through transparotid approach
Pharyngodynia and nocturnal hypoxia symptoms
Pleomorphic adenoma
Patient reported relief from nocturnal hypoxia, snoring, and sleep apnea symptoms, postoperatively
Small parotid swelling before 17 years, diagnosed as PA by FNAC. Surgery delayed for 10 years due to patient’s fear and then lost to follow-up. Swelling grew rapidly in past 6 months, causing gait disturbance and skin ulceration with foul-smelling, bloody discharge from the lower part of lesion
CT showed a nodular mass arising from the parotid gland and attached in its deeper aspect to the carotid sheath. Evidence of metastasis in chest radiograph owing to bilateral hilar lymphadenopathy and coin-shaped radiolucency in the right lung. Incision biopsy was indicative of PA, with clinical suspicion of malignancy
Total parotidectomy and en bloc resection of the tumor along with the lower portion of the auricle
(4.80 kg)
Rapid growth of tumor in last 6 months with cervical and thoracic scoliosis and gait disturbance
Nearly 80% of the resected tumor sections showed evidence of PA. Sections of the tumor near the ulcerated areas showed undifferentiated malignant cells indicative of carcinoma ex-PA
Postoperative adjuvant chemotherapy for metastasis
Large, multilobular preauricular mass with areas of ulceration and necrosis on overlying skin
CT showed a giant, exophytic mass in the superficial lobe of the parotid gland with multiple necrotic spaces and enhanced vascularity. Incisional biopsy was indicative of a salivary gland neoplasm without ruling out malignant transformation
Superficial parotidectomy with excision of overlying ulcerated skin
Pleomorphic adenoma with multiple foci of neoplastic proliferation, along with cellular atypia and necrosis. Final diagnosis carcinoma ex-PA
Postoperative radiotherapy 60 Gy
Patient died 8 months postsurgery due to cerebrovascular accident
Large, firm intraoral mass arising from the lateral pharyngeal wall, displacing the soft palate and crossing midline. Associated symptoms of difficulty in swallowing and breathing, and sleep apnea for past 6 months
CT showed parapharyngeal space mass extending medially across the midline and laterally between the posterior border of ramus and styloid process. MRI showed lobulated, homogeneous mass lesion extending from the deep lobe of the parotid gland with hypointense septae and measuring , and indenting on lateral pharyngeal wall. No involvement of skull base or intracranial extension was observed. Transoral FNAC was indicative of PA
Deep lobe parotidectomy through transcervical, mandibular split osteotomy approach
Difficulty in swallowing and breathing, and sleep apnea
Pleomorphic adenoma
Patient reported relief from sleep apnea symptoms, postoperatively
Large, nodular preauricular mass extending up to submandibular region inferiorly and anteriorly up to 2 cm posterior to the nasolabial fold
MRI showed a heterogeneous, lobulated mass in the superficial lobe of the parotid gland, extending medially up to sternomastoid and carotid sheath. FNAC was indicative of PA
Superficial parotidectomy with excision of redundant skin
Giant, multinodular, pedunculated mass in the preauricular region, extending up to the cervical region
MRI showed a giant, heterogeneous mass arising from the superficial lobe of the parotid gland, with well-demarcated boundaries and preservation of surrounding tissue planes. CT revealed primary blood supply though facial artery and numerous small feeder vessels. Incisional biopsy confirmed the diagnosis of PA
Extracapsular dissection of the tumor mass
(7.3 kg)
The mass became too big and a hindrance for the patient to ambulate
Giant, lobulated, and pedunculated mass in the preauricular region, extending up to cervical region, with firm consistency and measuring almost the size of the patient’s head
CT showed a large soft tissue mass arising from the superficial lobe of the parotid gland and presenting with several amorphous calcifications, but without any bony involvement. FNAC was indicative of PA
Superficial parotidectomy
(5.5 kg)
Patient had delayed surgery due to financial constraints
Pleomorphic adenoma with multiple foci of microcalcifications
Reactionary hemorrhage in the immediate postoperative period, managed through exploratory ligation. Transient neurological deficit of the buccal branch of facial nerve
Giant preauricular mass, fixed to underlying tissues and associated with facial nerve deficit (House-Brackman Grade III)
CT showed a well-defined parotid mass with mixed solid and cystic areas. The mass extended superiorly up to temporal muscle and cervically up to the hyoid bone. FNAC was indicative of mixed tumor of salivary gland origin
Extracapsular dissection of tumor mass along with a superficial skin island
Patient presented with a slow-growing, preauricular mass 1 year ago which was provisionally identified as PA through FNAC. Patient however delayed surgery due to personal reasons. Rapidly proliferating exophytic, firm, multilobulated growth with skin ulceration and bleeding were seen in the same lesion in the last 1 year. Facial nerve function was intact
CT showed a heterogeneous parotid mass measuring cm with foci of necrosis and calcification. The mass was in close proximity to inferior aspect of external auditory canal and was invading sternomastoid and masseter muscles. Superficially skin erosion was seen. No evidence of lymph node or bony involvement. FNAC was suggestive of carcinoma ex-PA
En bloc resection with total parotidectomy. Facial nerve branches except the buccal branch were preserved. The buccal branch was encased in tumor. Selective neck dissection (levels I-III) along with resection of infratemporal and parapharyngeal spaces. Soft-tissue reconstruction with anterolateral thigh free flap
10.5 cm diameter
Rapid growth with skin ulceration in the last 1 year
True malignant mixed tumor with extensive foci of necrosis and poorly differentiated adenocarcinoma and chondrosarcoma components. No histological evidence of original PA seen
Postoperative radiotherapy 60 Gy
At 3-year follow-up, no loco regional recurrence was observed. Patient however presented with lung and liver nodules on PET scan
Irregular, multilobulated, giant mass with a sessile base in the right parotid region extending to the neck. Overlying skin appeared erythematous with prominent vasculature and no discharge. Swelling was fixed to underlying tissues and facial nerve function was unaffected
CT showed a heterogeneous mass lesion arising from the parotid. MRI showed a lobulated heterogeneous mass with multilocular cystic changes and measuring . No extension to retromandibular or parapharyngeal spaces. FNAC was suggestive of PA
Superficial parotidectomy with preservation of facial nerve branches
(1.5 kg)
Patient was mentally challenged and patient’s mother requested surgery as the mass had become too large and hindered daily activities
Pleomorphic adenoma
1-year recurrence-free follow-up
Pareek et al. (2020) [32] (case series comprising 15 giant parotid PA)
30-81 years (mean—50.3)/5 males and 10 females
5-20 years
Right—9; left—6
All lesions were greater than 10 cm in diameter (range 10-25 cm)
Majority of the lesions presented as irregular or ovoid parotid masses with well-defined margins and overlying skin was ulcerated in 2 cases. None of the cases had preoperative facial nerve weakness
A combination of USG, CT, MRI, and FNAC to arrive at a provisional diagnosis of PA. One case was preoperatively diagnosed with malignant change based on FNAC
Total parotidectomy—10; total parotidectomy + neck dissection—1; superficial parotidectomy—3; enucleation—1. Facial nerve preserved in all cases
(2.0-3.5 kg; mean—2.7)
Majority of the patients delayed surgery due to poor awareness and underprivileged socioeconomic status
All cases were histologically confirmed as PA, except one case which showed a malignant change
Transient facial nerve deficit in 2 patients which recovered within 6 months. Postoperative radiotherapy only for the malignant case
