title: Percutaneous fine-needle aspiration biopsy in malignant lymphoma: a case report of an unusual cytologic presentation.
abstract: A case of an elderly Hispanic male who presented with clinical findings suspicious for lymphoma and cytologic evidence suggestive of carcinoma is presented and discussed. Percutaneous fine-needle aspiration biopsy of a group of mesenteric lymph nodes and a pleural fluid specimen showed clusters of tumor cells suggestive of carcinoma. Electron microscopic analysis of the pleural fluid showed comparable clusters of tumor cells, which proved to be lymphoma cells enveloped by macrophages. Histologic, electron microscopic, and histocytochemical examination of an enlarged inguinal lymph node confirmed the diagnosis of lymphoma with several alpha-naphthyl acetate esterase-positive macrophages interspersed among the tumor cells. To date, the phenomenon of macrophages enveloping lymphoma cells, so as to simulate tumor cell clustering, has not been reported. It is, however, an important possibility to keep in mind with cytologically distinguishing a lymphoma from a carcinoma.
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D006801:Humans; D007264:Inguinal Canal; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000201:enzymology / Q000473:pathology* / Q000648:ultrastructure; D008223:Lymphoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008643:Mesentery; D008854:Microscopy, Electron; D009283:Naphthol AS D Esterase / Q000032:analysis; D010996:Pleural Effusion / Q000473:pathology
chemical_list: D009283:Naphthol AS D Esterase