Imaging and Pathologic Findings of Peculiar Histologic Variants of Pancreatic Endocrine Tumors

Pancreatic endocrine tumors (PETs) are relatively uncommon, representing 1–2% of all pancreatic neoplasms. The detection of PETs has increased due to the development of sensitive diagnostic tools such as imaging techniques and reliable laboratory tests. This increased detection has resulted in the identification of a clinical and morphologic variety of PETs and a variety of histologic alterations including oncocytic changes, rhabdoid features, clear cytoplasm, mucin accumulation resulting in goblet cell formation, and spindle cell morphology (Chetty and Asa., 2004; Frankel, 2006), although they are rare. Such peculiar histologie features may make diagnosis difficult, especially in biopsy specimens. Therefore, diagnosis of PETs may better be performed according to radiologic findings. There are few reports concerning imaging findings of peculiar PETs. We report three cases, with imaging and pathologic findings: oncocytic PET, PET with rhabdoid features, and PET with clear cell cytology.