Lymphomatoid Granulomatosis and Tuberculosis, Coincidence or Cohabitation—A Case Report

Background: Lymphomatoid granulomatosis (LYG) is a rare and atypical EBV-induced B-cell lymphoproliferative disorder. Clinical manifestations are mainly respiratory, with nodular infiltrates, varying in number and size, being responsible for respiratory distress. Cutaneous, hepatic, or neurological involvement is also possible. Although pathogenesis is not clearly elucidated, quantitative or qualitative cellular immunodepression is thought to be a main factor. Here, we report a case of concomitant LYG and pulmonary tuberculosis. Case presentation: An 80-year-old female patient presented to the emergency unit for steadily increasing dyspnea, with workup revealing bilateral pulmonary nodules and mediastinal lymph node enlargement on chest imaging. Empiric antibiotic therapy was initially started with amoxicillin-clavulanate, which was later combined with azithromycin following respiratory deterioration. A CT-guided lung biopsy showed grade 2 LYG. Treatment with corticosteroids and weekly rituximab was initiated, leading to rapid improvement of respiratory symptoms. After the second dose of rituximab, sputum cultures that were initially collected were found to be positive for Mycobacterium tuberculosis. Rituximab was suspended, and antituberculous treatment was initiated. Rituximab was restarted once tuberculosis was controlled. Follow-up imaging later showed adequate control of both tuberculosis and LYG, with at least a partial remission of the latter. Conclusions: Our case highlights the importance of a complete diagnostic workup when a diagnosis of LYG is made, to avoid missing a concomitant pulmonary disease, such as tuberculosis, even when definite pathologic and clinical features of the former are present.