Giant-cell containing neoplasms of the pancreas: an aspiration cytology study.

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. (c) 2008 Wiley-Liss, Inc.