Cephalic undifferentiated carcinoma with osteoclast-like giant cells arising from the main pancreatic duct: case report and literature review.

Undifferentiated carcinoma with osteoclast-like giant cell (UCOGC) is a ductal carcinoma variant with a recently reported more protracted survival and pathognomonic histology comprising two cell populations: the mononuclear tumoral cells and nontumoral multinucleated giant cells. It usually presents as a large heterogenic tumor with mixed solid-cystic components. The tumor develops from the ductal epithelium but the sequence of epithelial changes is often not identified due to the rapid tumoral growth and associated necrotic changes. We report a case of a 76-year-old patient diagnosed with cephalic UCOGC originating in the epithelium of the main pancreatic duct with endoluminal growth and foci of other ductal neoplasms (high-grade pancreatic intraepithelial neoplasia (PanIN) and conventional ductal carcinoma). The particularity of our case consists in the identification of the columnar epithelium conversion, through high-grade PanIN, into UCOGC specific malignant features, in a large size tumor - aspect usually reported in small tumors. Alongside our case we also present a brief literature review of cephalic UCOGC case reports and case series.