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 nonfunctional 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.