FNA diagnosis of deep-seated lymphoma: an institutional experience

Controversy remains as to whether image-guided fine-needle aspiration (FNA) biopsy coupled with appropriate ancillary techniques has clinical utility in the diagnosis of deep-seated lymphomas.

A retrospective search (20 years) was performed to identify FNA cases with a definitive or indeterminate lymphoma diagnosis for deep-seated locations. The FNA diagnosis was compared with corresponding surgical pathology (SP) and clinical follow-up. The application of ancillary tests was also evaluated.

A total of 121 cases from 118 patients were recovered. Among 95 of 121 (79%) aspirates that had a definitive lymphoma diagnosis, 50 lacked SP follow-up. Most (82%) represented possible recurrent lymphoma, and thus therapy proceeded based on the FNA results alone. Additionally, 44 of 95 (46%) had an FNA diagnosis concordant with corresponding SP and 1 case was discordant. Of 44 with concordant SP diagnosis, 25 had further lymphoma subtyping that was concordant with SP. There were 26 of 121 (21%) with indeterminate diagnosis on FNAs. Of these, SP confirmed a diagnosis of lymphoma in 81%. Indeterminate cytologic diagnoses were due either to absent/inconclusive flow cytometry (FC) (11 of 21) or Hodgkin lymphoma (10 of 21). Of 121 cases, 93 utilized FC, 53 utilized cell-block immunohistochemical stains, and 29 utilized molecular testing as part of FNA work-up.

FNA plays an important role in the diagnosis/clinical management of deep-seated non-Hodgkin B cell lymphoma (NHL), particularly for recurrence. The addition of ancillary techniques, particularly FC, markedly increases NHL diagnostic accuracy and subclassification. Our study is one of the few large series examining the clinical utility of FNA in the setting of deep-seated lymphomas.