DIAGNOSTIC CHALLENGE OF LOBULAR CARCINOMA ON ASPIRATION CYTOLOGY

Lobular carcinomas are among the most difficult to type correctly on a spiration cytology. The inherent cytologic traits such as small size a nd bland appearance of cells in scanty aspirates may lead to false-neg ative diagnoses. Due to the low incidence of this form of bi east carc inoma, there are Sew studies solely on lobular carcinoma, and the cyto morphologic features are not well defined. To delineate the cytomorpho logic features and to assess their utility in correctly typing an aspi rate as lobular carcinoma, we undertook a retrospective review of fine -needle aspirates from 31 cases of lobular carcinoma. The cytologic fe atures of monomorphic cells, with scant cytoplasm, central vesicular n uclei, and inconspicuous nucleoli were found most helpful in correct t yping of the cases. Intracytoplasmic vacuoles, nuclear grooves, and '' Indian-file'' arrangement of cells were corroborating features. We pos tulate that a combination of cytologic features makes the diagnostic d elineation of lobular carcinomas possible on aspiration cytology. (C) 1998 Wiley-Liss, Inc.