Cytologic Diagnosis of Lymphomatoid Granulomatosis, A Case Report and Review of the Literature.

Lymphomatoid granulomatosis (LYG) is a rare EBV-driven, extra-nodal, angiocentric, and angio-destructive lymphoproliferative disorder. The lungs are the most common site of involvement. We describe a case of LYG where the diagnosis was established based on fine needle aspiration. The case is of a 58-year-old female with a history of endometrial carcinoma, who presented with right upper lobe and right middle lobe pulmonary nodules which were identified on a surveillance computed tomography (CT) scan of the chest. The patient underwent an endobronchial ultrasound-guided fine needle aspiration, and a cytologic examination showed mixed inflammatory infiltrate with histiocyte and small lymphocyte predominance and scattered large atypical cells. Immunohistochemical analysis showed that the large atypical cells were positive for CD30, PAX5, and MUM1. In situ hybridization for Epstein-Barr virus-encoded RNA was found to be positive in the atypical cells. The patient was started on treatment with peginterferon alfa-2a. We also discuss the differential diagnosis of LYG and review the available literature.