Flow Cytometry Analysis in Breast Implant-Associated Anaplastic Large Cell Lymphoma: Three Case Reports.

Breast Implant-Associated-Anaplastic Large Cell Lymphoma (BIA-ALCL) is a rare T-cell non-Hodgkin lymphoma associated with breast prosthetic implants and represents a diagnostic challenge. The National Comprehensive Cancer Network (NCCN) guidelines, updated in 2024, recommend for diagnosis an integrated work-up that should include cell morphology, CD30 immunohistochemistry (IHC), and flow cytometry (FCM). CD30 IHC, although the test of choice for BIA-ALCL diagnosis, is not pathognomonic, and this supports the recommendation to apply a multidisciplinary approach. A close collaboration between pathologists and laboratory professionals allowed the diagnosis of three BIA-ALCLs, presented as case reports, within a series of 35 patients subjected to periprosthetic effusions aspiration from 2018 to 2023. In one case, rare neoplastic cells were identified by FCM, and this result was essential in leading the anatomopathological picture as indicative of this neoplasm. In fact, the distinction between a lymphomatous infiltrate from reactive cells may be very complex in the cytopathology and IHC setting when neoplastic cells are rare. On the other hand, one limitation of FCM analysis is the need for fresh samples. In this study, we provide evidence that a dedicated fixative allows the maintenance of an unaltered CD30 expression on the cell surface for up to 72 h.