Cytologic features and clinical implications of undifferentiated carcinoma with osteoclastic giant cells of the pancreas: An analysis of 15 cases

BACKGROUND: The cytologic features of undifferentiated pancreatic carcinoma with osteoclastic giant cells (UOC) are rarely described. METHODS: Cytologic and clinicopathologic characteristics in 15 UOC fine-needle aspiration (FNA) specimens were analyzed. RESULTS: FNA specimens were obtained from 6 men and 8 women with a mean age of 65 years who had UOCs (head, n = 7; body, n = 3; and tail, n = 4) with a mean radiologic size 7.3 cm, and some had a cystic component (n = 9). Three cell types (osteoclastic giant cells, pleomorphic tumor giant cells, and spindled/histiocytoid cells) were observed in 12 of 15 specimens (80%); and pancreatic ductal adenocarcinoma (PDAC) was present in 11 specimens. FNA diagnoses were UOC (n = 6), PDAC (n = 5), poorly differentiated carcinoma (n = 2), “suspicious for neoplasm” (n = 1), and “negative” (n = 1). Five of 5 specimens with osteoclastic giant cells were positive for cluster of differentiation 68 (CD68) (a glycoprotein that binds to low-density lipoprotein). Pleomorphic tumor giant cells and spindled/histiocytoid cells were positive for pancytokeratin (6 of 7 specimens), CAM5.2 (2 of 3 specimens), and epithelial membrane antigen (2 of 2 specimens). INI-1 protein expression was retained in 3 of 3 specimens. The Ki-67 labeling index was assessed in 3 specimens and was 12%, 18%, and 40%; 4 of 12 resected UOCs were pure, and 8 were mixed with PDAC. One resection specimen had intraductal papillary mucinous neoplasm, and 2 had mucinous cystic neoplasms. The median overall survival (OS) of patients who had UOCs identified on FNA was 8 months (6 died [OS, 8 months; range, 2-22 months], and 8 remained alive [OS, 3 months; range, 1-27 months]), which was similar to the survival of 74 patients who had PDACs identified on FNA (OS, 15 months; P =.279) but worse than that of the 27 patients with UOCs who did not undergo FNA (OS, 92 months; P =.0135). CONCLUSIONS: The 3 classical UOC cell types are identifiable on FNA, making cytologic diagnosis possible if considered in the differential. A PDAC component is often also observed. The survival advantage of UOC over pure PDAC appears to be negated by FNA and requires further investigation. Cancer Cytopathol 2017;125:563–75.