Case of the fortnight

Malignant Schwanoma of Sciatic Nerve

A 22 year old lab technician working in a hospital complains of  severe pain on right leg  in the  gluteal region which has been there for 4 months.Later he had some numbness on the lateral side of leg on walking. An ill defined swelling in the left gluteal region was made out on clinical edxamination.  An MRI of the area was done and a   7 X 5  cm tumour involving the left sciatic nerve was found.  With this picture he was refered to the Plastic, Hand and Microsurgery department
MRI of the left thigh showing the tumour along with the sciatic nerve.
On exploration of the left gluteal region

Operative Procedure
By a longitudinal incision in the gluteal region, by a muscle splitting incision the tumour was approached.A 7cm X 5 cm tumour invading the sciatic nerve was found, just distal to the ischeal  tuberosity.  50% of the nerve was found stretched on the lateral side and 40%was found anterior to the tumour.  After initial identification of the tumour surgery was done under magnification through microscope.  The nerve was fully dissected proximal and distal to the tumour and all the major fascicles were followed through the tumour and  freed.  90% of the nerve was protected and whole of the tumour was excised.Post operatively he has no motor weakness.
The sciatic nerve seen along the margin of the tumour. The intact sciatic nerve after microneural dissectionof the tumour

Histopathology : Malignant Schwanoma

Remarks
Neural tumours affecting major nerves like sciatic nerve are rare.  When they occur very proximally,  surgery is challenging because damage to the fascicles would result in debilitating paralysis.  Microscope and fine instruments are very essential.  Patience and haemostasis are essential during dissection.  The surgical procedure took three and half hours but is a small price to pay to escape from paralysis of important  muscles.