Sarcoidosis or Sarcoid-like Reaction? Diffuse Large B-Cell Lymphoma Diagnosed Months After Mediastinal Granulomas: A Case Report and Review of Published Cases

Background and Clinical Significance: Sarcoidosis and lymphoma may precede, follow or accompany each other, and lymphoma can also induce a sarcoid-like granulomatous reaction. Case Presentation: We describe a 62-year-old woman with exertional dyspnea, abdominal pain and fluctuating cervical lymphadenopathy. Computed tomography showed mediastinal, hilar and abdominal lymphadenopathy with hepatosplenomegaly; a subcarinal lymph node obtained by mediastinoscopy showed non-necrotizing granulomas, and sarcoidosis was diagnosed and managed with observation. Four months later, worsening dyspnea and progressive lymphadenopathy led to FDG-PET/CT, which showed markedly hypermetabolic cervical nodes (SUVmax 20.5) but only moderate mediastinal uptake (SUVmax 4.8). Excisional cervical lymph node biopsy established diffuse large B-cell lymphoma (DLBCL), non-germinal-center B-cell phenotype, and Ann Arbor stage IIIS-A. After six cycles of R-CHOP, she achieved a complete metabolic response and remains in remission three years after treatment. Because both diagnoses were established within one year and lymphoma had initially been excluded on a single mediastinal node, a lymphoma already present at first presentation with an accompanying sarcoid-like reaction cannot be ruled out. Conclusions: In patients labeled as having sarcoidosis, peripheral or abdominal lymphadenopathy, splenomegaly and discordant FDG uptake should prompt excisional biopsy of the most accessible FDG-avid node, ideally before corticosteroids are started. Thirty-nine published cases of sarcoidosis associated with DLBCL are summarized.