Undifferentiated Carcinoma With Osteoclast-like Giant Cells of the Pancreaticobiliary Tract: A Single Tertiary-Care-Oncology Center Case Series

<b>Context.</b> Undifferentiated carcinomas with osteoclast-like giant cells of the pancreaticobiliary tract (UCOGCs) are rare but distinctive tumors with limited literature. <b>Objective.</b> To study the clinicopathologic characteristics of UCOGCs including morphology, immunohistochemistry (IHC), management, and survival outcomes. <b>Design.</b> Assessment of 12 patients of UCOGC found over 10 years from a tertiary care oncology center database. <b>Results.</b> The mean age at diagnosis was 54.8 years (35-69 years) with a striking men:women ratio of 1:1.5. Eleven of 12 tumors (91%) involved the pancreas, while 1 was in the gallbladder fossa (8%). The mean tumor size was 8.8 cm (range: 4.2-18 cm). Fifty-eight percent showed metastasis at presentation, most commonly to the liver (57%). On microscopy, epithelioid-predominant histology was seen in 91%; 5 of these had an additional spindle/sarcomatoid morphology, while 1 tumor showed pure sarcomatoid histology. By immunohistochemistry, keratins were expressed in the neoplastic mononuclear cells (6 of 9, 67%). In terms of management, 2 of 11 (18%) patients underwent surgery alone; 1 of 11 (9%) received neoadjuvant chemoradiation, followed by surgery and adjuvant chemotherapy; 2 of 11 (18%) underwent surgery, followed by adjuvant chemotherapy; 4 of 11 (36%) received chemotherapy alone; and 2 of 11 (18%) received palliative care. On follow-up, 9 of 12 patients succumbed within a year of diagnosis (75%). The 6-month overall survival (OS) was 44%, and the mean survival period was 5 months (range: 8 days-1 year). <b>Conclusions.</b> UCOGCs are rare, aggressive variants of carcinoma and ought to be classified separately. Owing to their unique etiopathogenetic mechanisms, further exploration and large studies are required to devise newer, more effective therapeutic regimes.