Osteitis fibrosa cystica (brown tumor) in a patient with renal transplantation. Report of a case with aspiration cytodiagnosis.

The cytologic findings from fine needle aspiration of a left shoulder mass are described for a woman who had undergone renal transplantation and on whom an orthopedic consultation suggested the clinical possibility of a soft tissue sarcoma. The aspirate samples from multiple sites in the mass showed several multinucleate, osteoclast-type giant cells, spindly or fibrillary cells with ovoid nuclei and a significant amount of granular calcium. The needle aspiration cytodiagnosis was of critical importance since it saved the patient from invasive surgical intervention. This case emphasizes the role of needle aspiration cytology in providing a rapid cytodiagnosis of osteitis fibrosa cystica with a minimally invasive method.