Peripheral nerve sheath tumour of the sciatic nerve

Case contributed by Dr Ivan Turkalj

Presentation

A female patient referred for MRI due to a incidentally detected soft tissue mass at duplex scan examination. She denied any discomfort and pain in the region of the lesion. Previous history was unremarkable.

Patient Data

Age: 55-year-old
Gender: Female

There is a fusiform T1W hypo- and T2W centrally hypo- and peripherally hyperintense lesion (target sign) in the posterior part of the thigh, closely related to the sciatic nerve. The lesion enhances vividly and homogeneously after contrast administration. 

A note is made of minor medial meniscus extrusion and tibial subchondral cyst associated with cartilage degeneration. Also, a small ganglion cyst near the attachment of the lateral head of gastrocnemius muscle is evident.    

Case Discussion

According to clinical and MR findings, a diagnosis of peripheral nerve sheath tumour of the sciatic nerve was made.

An enhancing fusiform mass in continuity with a neurovascular bundle is virtually diagnostic for peripheral nerve sheath tumour. Target sign, as shown in the present case, was previously assumed to be pathognomonic of neurofibroma, however, it has been observed in both neurofibromas and schwannomas and has even been reported in malignant peripheral nerve sheath tumours.  

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Case Information

rID: 41283
Case created: 24th Nov 2015
Last edited: 13th Oct 2016
Inclusion in quiz mode: Included

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