Background: Extraosseous giant cell tumors involving visceral organs (pancreas, kidneys, bladder, etc.) and soft tissues present similar histological features to those occurring in the bones. Rarely, they may affect pancreas and their origin remains still controversial, with some authors supporting the epithelial and some others the mesenchymal origin. Case Presentation: We report the case of a pancreatic giant cell tumor with osteoclast-like cells, negative for epithelial markers. A 64-year-old man presented with a 2-month history of progressively worsening abdominal pain, radiating to the lumbar region. He reported no other symptoms. The abdominal clinical examination was unremarkable and there was no associated jaundice. Liver function tests remained within normal limits. His past medical history had nil of note. He underwent an outpatient abdominal computed tomography which revealed a large cystic lesion at the body of the pancreas measuring 10 × 7 × 6.5 cm. We proceeded with a limited excision of the pancreatic mass alone, avoiding major dissections that would unnecessarily increase morbidity and mortality and the postoperative course was good. The histological morphological and immunohistochemical assessment revealed two tumor cell types: osteoclast-like multinucleated giant cells and pleomorphic mononuclear cells, with bone formation and without important cellular and nuclear atypia. Conclusion: Pancreatic giant cell tumors with osteoclast-like giant cells are rare tumors of the pancreas with various clinical characteristics and controversial origin. En bloc resection has prevailed as the only beneficial treatment so far.

Keywords: Osteoclastic giant cell tumor of the pancreas, bone, osteoid