Sarcoid-like reaction

Case Discussion

Sarcoid-like reactions have been reported in association with various malignancies, including lung, breast, and renal cancer ^1-3. While the exact pathogenesis of this phenomenon remains unclear, it is likely an immunological response to tumor antigens. The activation of immune cells and subsequent granuloma formation may be the result of the release of various cytokines and chemokines within the tumor microenvironment which may travel and seed distant sites ⁴. These reactions tend to occur most often post-immunotherapy treatment ^5,6. Sarcoid-like reactions have been described as a positive prognostic factor in some malignancies, suggesting an enhanced immune response against the tumor although this is still being studied ^3,7.

The case presented here highlights the importance of a thorough evaluation and staging in patients with newly diagnosed prostate cancer. The PET-CT scan revealed findings consistent with the known malignancy, as well as potential osseous metastatic disease. However, the presence of FDG-avid mediastinal and hilar lymph nodes is unusual in the absence of tumor spread to local structures, raising suspicion for a sarcoid-like reaction ⁸. The patient also lacked a history of inflammatory disease or sarcoidosis that might be manifesting or worsening in the setting of malignancy. Understanding and recognizing sarcoid-like reactions in cancer patients that have not yet undergone treatment is essential for accurate staging and appropriate treatment. These hilar lymph nodes could be biopsied to rule out metastatic disease, but observation is also appropriate in this case.

Thank you Dr. Hunter Hamilton, MD and Dr. Russ Kuker, MD from the University of Miami and Jackson Memorial Hospital Health System for your contribution and help in this interesting case.