Fine needle aspiration diagnosis of intraabdominal and retroperitoneal lymphomas by a morphologic and immunocytochemical approach

We reviewed 238 fine needle aspiration biopsies (FNA) of intraabdominal or retroperitoneal (IA/RP) masses in 192 patients with known or suspected lymphoma. A limited battery of immunocytochemical stains, including kappa (k) and lambda (l) light chains and Leu‐4, was performed in 104 aspirates. On hundred twenty‐eight of the FNA were diagnostic of or consistent with lymphoma, and three were diagnostic of carcinoma. Twenty‐eight were considered negative for malignancy and 79 were suspicious for lymphoma or were nondiagnostic. For 135 of the FNA, a histologic biopsy specimen was available for comparison purposes. Overall, only one false‐positive result was seen in a specimen lacking immunocytochemical data. The sensitivity of FNA lymphoma diagnosis was 66%. False‐negative results due to sampling error were not uncommon, giving a predictive value of a negative result as 42%. The classification of the lymphomas by FNA was identical to that of the surgical biopsy in 86% of specimens and concurrently discrepant in 6%. We conclude that the routine performance of immunocytochemical studies on FNA of IA/RP masses is a feasible and valuable technique. Whereas suboptimal sensitivity and sampling error may make a negative diagnosis unreliable, lymphoma marker studies (combined with morphology) allow for an accurate and confident diagnosis and subclassification of lymphoma in the majority of cases.