Lymph node fine needle Cytology in the staging and follow-up of Cutaneous Lymphomas

Background: Lymph nodal involvement is an important clinical-pathological sign in primary cutaneous lymphoma (PCL), as it marks the transformation/evolution of the disease from localized to systemic; therefore the surveillance of lymph nodes is important in the staging and follow up of PCL. Fine needle cytology (FNC) is widely used in the diagnosis of lymphadenopathies but has rarely been reported in PCL staging and follow-up. In this study an experience on reactive and neoplastic lymphadenopathies arisen in PCL and investigated by FNC, combined to ancillary techniques, is reported. Methods: Twenty-one lymph node FNC from as many PCL patients were retrieved; 17 patients had mycosis fungoides (MF) and 4 a primary cutaneous B-cell lymphoma (PBL). In all cases, rapid on site evaluation (ROSE) was performed and additional passes were used to perform flow cytometry (FC), immunocytochemistry (ICC) and/or polymerase chain reaction (PCR) to assess or rule out a possible clonality of the corresponding cell populations. Results: FNC combined with FC, ICC, and PCR identified 12 cases of reactive, non specific, hyperplasia (BRH), 4 dermatopathic lymphadenopathy (DL), 4 lymph nodal involvement by MF and 1 lymph nodal involvement by cutaneous B-cell lymphoma. Conclusions: FNC coupled with ancillary techniques is an effective tool to evaluate lymph node status in PCL patients, provided that ROSE and a rational usage of ancillary techniques is performed according to the clinical context and the available material. The method can be reasonably used as first line procedure in PCL staging and follow up, avoiding expensive and often ill tolerated biopsies when not strictly needed.