Fine needle aspiration diagnosis of orbital plasmacytoma with amyloidosis. A case report.

Fine needle aspiration (FNA) cytology of the orbit was used to diagnose an unusual case of multiple myeloma with secondary amyloid deposition in a 27-year-old man who presented with bilateral keratoconjunctivitis and left-sided ptosis. The FNA smears revealed immature plasma cells, extracellular eosinophilic material (amyloid) and numerous multinucleate giant cells. Subsequent histologic studies of excised tissue confirmed the cytologic diagnosis of plasmacytoma with secondary amyloidosis. Amyloid was further confirmed by electron microscopy. The patient was subsequently diagnosed as having multiple myeloma. The cytologic features of amyloidosis and plasmacytoma are presented. The differential diagnosis and the diagnostic utility of FNA cytology in the evaluation of these orbital lesions are also discussed. This apparently was the first case of orbital amyloidosis diagnosed by FNA cytology.