A Rare Case of Calf Muscle Metastasis from a Non-Functional Pancreatic Neuroendocrine Carcinoma.

Abstract

Pancreatic neuroendocrine tumors (PNET) are uncommon pancreatic neoplasms, accounting for 1-2% of all pancreatic tumors. However, they have a better prognosis and long-term survival compared to exocrine pancreatic cancer. PNETs can be divided into functional or non-functional based upon whether or not they excrete active substances relevant to specific clinical syndromes. Skeletal muscle metastasis is also a rare condition and differentiation between a primary soft tissue sarcoma and metastatic carcinoma is difficult without biopsy. Thus, skeletal muscle metastases from pancreatic neoplasms are exceedingly rare, with only a few cases reported in the literature. We present a 34-year-old man with metastatic pancreatic neuroendocrine carcinoma that was initially thought to be a primary soft tissue tumor. Pathology and immunohistochemistry demonstrated the tumor to be a metastasis from a pancreatic neuroendocrine carcinoma. A brief review of the literature on this subject is also presented.