This massive tumour has a lobulated outer surface; it appears to be infiltrating muscle and the cut
surface shows numerous areas of haemorrhage and necrosis.
This woman presented at the age of 23 with left foot drop; examination showed
neurofibromatosis with a large mass in the left thigh. The tumour was found to arise from the
lateral popliteal nerve and was removed; it extended from the intertrochanteric line to the apex
of the popliteal fossa. It weighed 2785 grams. Removal was followed by chemotherapy but within
a few months there was a local recurrence which was irradiated. Some months later the
development of focal fits led to the demonstration of lung and brain metastases.