Case Reports in Radiology

The raccoon roundworm Baylisascaris procyonis (B. procyonis) may infect humans to cause severe or fatal meningoencephalitis, as well as ocular and visceral larva migrans. Young children are at greater risk for cerebral larva migrans with severe meningoencephalitis, and early empiric therapy may improve outcomes. Familiarity with characteristic brain imaging findings may prompt earlier diagnosis, particularly in the setting of CSF eosinophilia. We report a case of a 19-month-old boy who presented with truncal ataxia and was found to have peripheral and CSF eosinophilia. MRI demonstrated symmetric, confluent T2 hyperintense signal in the cerebral and cerebellar deep white mater, which helped differentiate B. procyonis meningoencephalitis from other infectious and non-infectious causes of eosinophilic meningoencephalitis. Early recognition and treatment of B. procyonis meningoencephalitis are important for improved outcomes, and careful review of neuroimaging can play a critical role in suggesting the diagnosis.

We present the case of a 22-year-old man who was diagnosed with tonsillitis and treated with antibiotics. Although the symptoms subsided, 1 week later, he presented with weakness in the lower limbs and was hospitalized. The weakness in the lower limbs worsened; he developed difficulty speaking and was transferred to our hospital. Laboratory tests showed a white blood cell count of 10,600/μL (24% atypical lymphocytes). Positive results were obtained for immunoglobulin M (IgM) antibody against Epstein-Barr virus (EBV) viral capsid antigen. EBV-deoxyribonucleic acid quantification in blood yielded positive results. Magnetic resonance imaging (MRI) revealed a hyperintensity in the spinal cord at the Th11 level of the lower spine on T2-weighted imaging (T2WI). In addition, T2WI and fluid-attenuated inversion recovery imaging showed hyperintense lesions on the right cerebral peduncle, bilateral thalami, posterior leg of the left internal capsule, and right corona radiata. We diagnosed acute disseminated encephalomyelitis (ADEM) with EBV and initiated steroid pulse therapy. Symptoms, along with the lesions seen on MRI, subsequently ameliorated. This case suggests that ADEM can be difficult to diagnose, but careful diagnosis is crucial since appropriate treatment is necessary to improve the symptoms.

Dermatofibrosarcoma protuberans is a low-grade cutaneous sarcoma typically located on the trunk or proximal extremities. Less common locations include the head, face, and neck area. This tumour is slow growing with variable clinical appearance. It is known for its locally invasive nature and low metastatic propensity. Because imaging findings are rather nonspecific, biopsy is needed for definite diagnosis. This case describes an unusually large example of dermatofibrosarcoma protuberans in the less common preauricular region.

Median raphe cysts are uncommon benign cysts thought to occur due to improper fusion of the genital tubercle and can occur anywhere along the median raphe, from the glans to the anus, most commonly occurring along the ventral penile shaft. Limited information is available in the literature about the common imaging features of median raphe cysts with available reports highlighting an avascular cystic lesion. Our case demonstrates a 10-year-old male patient presenting with a ventral penile mass that demonstrated interval growth in the absence of trauma without overlying skin changes. Doppler ultrasound examination demonstrated a solid vascular mass measuring up to 1.6 cm at the ventral aspect of the penis with arterial and venous waveforms. The patient underwent elective resection of the mass which revealed a 2.0 cm inflamed glandular subtype median raphe cyst. This report demonstrates an atypical imaging presentation of an inflamed median raphe cyst, particularly that of a heterogeneous solid mass with arterial and venous blood flow on ultrasound.

Dynamic imaging of heart valves and specifically prosthetic valves is a central benefit of echocardiography. Most bioprosthetic heart valves degenerate over a given time and hence require repeat valve replacement which carries a significant risk of morbidity and mortality. Reoperation is the standard of care and may still be required after the first successful surgery due to complications disrupting either mechanical or bioprosthetic valves. Such complications can be delayed or even prevented if optimal prosthesis selection is individualized according to patients’ medical and postimplantation follow-up. We present the case of an 84-year-old woman where an open-heart valve-in-valve approach, implanting a mechanical valve in a failed bioprosthetic valve, produced a unique image on transthoracic echocardiography which needs to be recognized by imagers for appropriate patient diagnosis and management.

Pancreatic pseudocysts are a common complication of pancreatitis. However, mediastinal extension of a pseudocyst is rare and often presents with atypical symptoms. We present a case of mediastinal extension of a pancreatic pseudocyst in a 56-year-old woman with a history of alcohol-related chronic pancreatitis, who presented with acute on chronic epigastric abdominal pain and atypical chest pain. Serum lipase was elevated, and imaging by contrast-enhanced computed tomography (CT) demonstrated a paraesophageal fluid collection. This collection was continuous with a peripancreatic pseudocyst and extended into the posterior mediastinum via the esophageal hiatus. Mediastinal extension of a pancreatic pseudocyst was confirmed by magnetic resonance imaging (MRI). The patient was managed conservatively in the hospital with parenteral nutrition therapy, pain control, and close imaging observation. The patient was discharged home to continue conservative management and close imaging follow-up. An initial follow-up CT examination 8 weeks after discharge revealed interval decrease in the posterior mediastinal collection but also interval development of loculated left pleural and pericardial effusions.