When Location Misleads: Plasma Cell Neoplasm Diagnosed by Fine-Needle Aspiration Cytology

Abstract

Plasma cell neoplasms (plasma cell dyscrasias) are a group of disorders characterized by the neoplastic proliferation of a single clone of plasma cells, which usually produces a monoclonal immunoglobulin and are rarely diagnosed in cytology. Fine-needle aspiration cytology (FNAC) in these patients may aid in early and definitive diagnosis, thus helping inappropriate management of such patients. We report a case of a 70-year-old male with swelling over the right-side clavicle. On ultrasound of the neck, an ill-defined heteroechoic solid lesion was noted in the subcutaneous and deep muscle planes, with underlying clavicle showing cortical discontinuity. FNAC aspirate exhibited sheets and scattered plasma cells and was diagnosed as a plasma cell neoplasm.