Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas diagnosed by endoscopic ultrasound guided biopsy.

Undifferentiated pancreatic carcinoma with osteoclast-like giant cells is a rare tumour that has been published under a wide variety of names, including pleomorphic carcinoma, giant cell carcinoma, sarcomatoid carcinoma and carcinosarcoma, among others. For these reasons and its low frequency, the reports of these tumours are scarce and frequently lead to confusion with other entities which present with giant cells. We present the case of a patient with obstructive jaundice and a mixed cystic and solid pancreatic mass, accompanied by multiple hepatic lesions. The histological study of the material obtained by endoscopic ultrasound guided biopsy demonstrated a proliferation of atypical epithelioid cells, accompanied by a spindle cell component with marked pleomorphism and numerous osteoclast-like giant cells. The epithelioid component showed positive immunostaining with cytokeratin cocktail and cytokeratin 7. The spindle cell component showed coexpression of cytokeratins and vimentin. The osteoclast-like giant cells were positive for CD68. Protein p53 was overexpressed in both epithelial and spindle cell neoplastic components, and was negative in the giant cells. These findings permitted the diagnosis of undifferentiated carcinoma of the pancreas with osteoclast-like giant cells. This case outlines the effectiveness of endoscopic ultrasound-guided biopsy and the importance of morphological and immunohistochemical examination in the diagnosis of different types of pancreatic tumours, especially when they are in advanced stages and are not suitable for surgical treatment.