EUS-guided fine needle biopsy is able to provide diagnosis in rare osteoclast-like giant cells undifferentiated carcinoma of the pancreas: report of two cases.

Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells (UC-OGC) is a rare subtype of pancreatic cancer, accounting for less than 1% of all pancreatic tumors. Preoperative diagnosis is cumbersome as cross-sectional imaging is often not capable to distinguish between UC-OGC and other pancreatic tumors such as pancreatic adenocarcinoma, mucinous carcinoma or neuroendocrine tumors and specific tumor markers seem to be lacking. Endoscopic ultrasound r `m(EUS) with tissue acquisition via fine-needle aspiration (FNA) or biopsy (FNB) with microscopic HE staining and immunohistochemistry allows for an accurate diagnosis, thus influencing further treatment.