Malignant peripheral nerve sheath tumor of the pancreas-A case report.

Introduction: Nerve sheath tumors are tumors arising from nerve sheaths or which show nerve sheath differentiation. They are divided as benign and malignant. They are associated with Von Recklinghausen syndrome. Characterised by café-au-lait spots, lisch nodules, acoustic neuromas, pheochromocytomas.

Presentation Of Case: A 62 year old gentleman came with complaints of Abdominal discomfort for 1month. He also had Left sided abdominal pain, Anorexia, Vomiting, No history of dyspepsia, fever, bowel disturbance. Patient is a known case of diabetes mellitus II. On abdominal examination a large mass of 10*8 cms was palpated in the left hypochondrium, left lumbar, and umbilical region. It had restricted mobility, not moving with respiration, firm in consistency. On palpation of neck, the thyroid gland was found to be enlarged with palpable right lobe. Contrast enhanced computed tomography showed large lobulated heterogenously enhancing mass with internal necrosis and calcifications in the left hypochondrium, in the region of distal body and tail of pancreas. There were no other foci of metastasis in abdomen or chest. Chest X-ray of patient was normal. Ultrasound of neck revealed a suspicious nodule in right lobe of thyroid measuring 1*1 cms with no nodal enlargement. Fnac of thyroid nodule was done under image guidance which was suggestive of papillary carcinoma of thyroid. As image guided biopsy of abdominal tumour could not be done patient was planned for laparotomy. The tumor was resected en bloc - distal pancreatectomy and splenectomy. Post opereative biopsy showed irregular spindle shaped cells with nuclei exhibiting "a wavy, buckled appearance" malignant peripheral nerve sheath tumor. Patient was reviewed after a period of 2 months. Positron emission tomography was done which revealed para aortic nodes and 2 mesenteric nodes. It also revealed a metabolically active nodule in thyroid with cervical nodal metastasis. Patient was taken up for total thyroidectomy with functional neck dissection. Histopathology confirmed papillary carcinoma of thyroid with positive lymph nodes. Patient was advised to undergo a radioactive iodine scan showed 0.3% uptake. Patient was started on chemotherapy for para aortic nodes with a regimen of paclitaxel, adriamycin, ifosumide and mesma.

Discussion: Pancreatic schwannoma arise from sympathetic and Para sympathetic fibers that cross over pancreas. Patients Present with abdominal pain and weight loss commonly. Macroscopically they are well circumscribed, encapsulated lesions, homogenous lesions. Microscopically they show Antoni A & B areas. They demonstrate S100, vimentin, CD56 positivity. Most common differential diagnosis are cystic mucinous / serous neoplasms of pancreas. Malignant transformation is extremely rare with only 8 reported cases till now. Treatment is simple enucleation, but a accurate pre-operative diagnosis is difficult to make hence a oncollogically margin negative resection is done. Adjuvant radiotherapy can be given to reduce the tumor load. Chemotherapy can be given with ifosumide and doxorubicin.

Conclusion: Malignant pancreatic nerve sheath tumours are very rare to be found, but have very poor prognosis, hence in cases of pancreatic tumour its better to keep the diagnosis of nerve sheath tumour also a differential diagnosis. In conclusion pancreatic tumours are to be identified at the earliest and surgery should be done for those cases.