Fine-needle cytology and flow cytometry assessment of reactive and lymphoproliferative processes of the breast.

Objective: The breast may be affected by reactive and lymphoproliferative processes such as primary (PBL) or secondary (SBL) lymphoma, reactive intramammary lymph nodes and sclerosing lobulitis; imaging may be not specific and surgical treatment not indicated. We report an experience with fine-needle cytology (FNAC) combined with flow cytometry (FC) and immunocytochemistry (ICC) in the diagnosis of these processes. Study Design: Thirty-seven cases comprising intramammary lymph nodes (n = 15), sclerosing lobulitis (n = 2), PBL (n = 11) and SBL (n = 9) are reported. FNAC was used to prepare traditional smears, conventional ICC or FC. Cytological diagnoses were compared to the imaging data, checked by histology or follow-up and statistically evaluated. Results: Imaging was not conclusive in most PBL, SBL, sclerosing lobulitis and some intramammary lymph nodes. FNAC combined with FC and ICC provided a definitive diagnosis of intramammary lymph node, sclerosing lobulitis, PBL and SBL in 18 cases with indication of the specific subtype in 10 cases. Statistical analysis showed 90% sensitivity, 100%specificity, 100% positive predictive value and 89% negative predictive value. Conclusions: FNAC combined with FC and ICC is a helpful procedure for the diagnosis of reactive and lymphoproliferative processes of the breast. It may prevent unnecessary biopsy and speed up therapeutic procedures.