Abstract
Giant‐cell containing neoplasms of the pancreas are rare with few reports documenting their cytologic appearance. Giant‐cell containing neoplasms of the pancreas have been divided into two subtypes corresponding to the osteoclastic giant‐cell tumor of the pancreas and the pleomorphic giant‐cell carcinoma of the pancreas. Despite the better prognosis reported in some series for osteoclastic giant‐cell tumors, the most recent edition of the World Health Organization classification lumps the two entities into a single category designated as undifferentiated carcinoma with osteoclast‐like giant cells. Smears obtained from osteoclastic giant‐cell tumors show numerous giant‐cells with clustered overlapping, bland appearing nuclei containing prominent nucleoli consistent with an osteoclast‐type multinucleated giant‐cell. These neoplasms contain a second population of mononuclear cells showing more marked nuclear atypia. Pleomorphic giant‐cell carcinomas are characterized by anaplastic giant‐cells displaying marked nuclear pleomorphism. The mononuclear component is also pleomorphic with markedly atypical epithelioid and spindle shaped cells. In three reported cases, a tumor contained a mixture of the two cell patterns. Thus, undifferentiated carcinoma with osteoclast‐like giant cells and pleomorphic giant cell carcinoma may represent a morphologic spectrum with pure osteoclast‐like giant‐cell tumors at one end and pleomorphic giant‐cell carcinoma at the other. Fine‐needle aspiration specimens from pure osteoclast‐like giant‐cell tumors will contain a population of bland multinucleated osteoclastic‐like giant‐cells that differ markedly from the anaplastic giant‐cells of pleomorphic giant‐cell carcinoma. The difference in the appearance of the giant‐cells aids in distinction of the two neoplasms. When in pure form, the two neoplasms may follow different clinical courses. Diagn. Cytopathol. 2008;36:238–244. © 2008 Wiley‐Liss, Inc.