Functioning pancreatic acinar cell carcinoma: immunohistochemical and ultrastructural analyses.

Acinar cell carcinoma (ACC) of the pancreas is a rare malignancy accounting for < 1% of pancreatic neoplasms. We report the clinical and biological characteristics of this carcinoma from two cases that were of interest because of their similar presentation: extensive subcutaneous fat necroses from excessive lipase production by these tumors. Immunohistochemical and ultrastructural analyses of both tumors were consistent with an acinar cell line origin. Recognition of the association between subcutaneous panniculitis and pancreatic neoplasm may prevent long delays in the diagnosis and treatment of this malignancy.