Cytologic aspect of brown tumor of hyperparathyroidism. Report of a case affecting the hard palate.

The cytologic and histologic findings of one brown tumor (BT) of hyperparathyroidism located in the hard palate, at first misdiagnosed as peripheral giant-cell granuloma, are described. Poor communication between cytopathologist and ear nose and throat specialist was responsible for the error. The overriding cytologic finding was the presence of numerous multinucleated giant cells (MGCs) of the osteoclastic type. MGC-rich aspirates pose the same diagnostic dilemmas as those of histologic sections of MGC-containing lesions of bone: these cells are not diagnostic by themselves and can be seen in several benign and malignant conditions. Clinical history, X-ray films and biochemical findings, particularly serum parathormone levels, are essential to diagnose a BT and to rule out other MGC-rich bone lesions.