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Non infectious epithelioid cell granulomas associated with lymphadenitis appear secondary to conditions such as berylliosis, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, lymph nodes draining cancer, Crohn’s disease, sarcoidosis and sarcoid-like reaction. Centric necrosis and abscess concurring within aforesaid granulomatous reaction is exceptional. Non necrotising or ‘naked granulomas’ may display features such as focal aggregates of epithelioid histiocytic cells, giant cells and miniscule, marginal exudate of chronic inflammatory cells, akin to sarcoid granulomas. Of obscure pathogenesis, an immunological response to tumour antigens is posited to contribute to occurrence of sarcoid-like reaction. Activation of immune cells and subsequent configuration of epithelioid cell granuloma may occur on account of secretion of various cytokines and chemokines within the tumour microenvironment which transmits to and impregnates distant sites and organs [1,2].

Sarcoid-like reaction is frequently encountered following immunotherapy. Sarcoid-like reaction appears to configure as an indicator of superior prognosis within certain malignancies and is associated with augmented immune response against the tumour [1,2]. Sarcoid-like reaction elucidates epithelioid cell granulomas recapitulating sarcoid nodules, confined to regional lymph nodes. The reaction is associated with concomitant disease processes. Nevertheless, sarcoid-like granuloma may not indicate occurrence of systemic sarcoidosis. Concurrent inflammatory disease or sarcoidosis manifesting or worsening with malignant disorders may be absent [2,3]. Sarcoid-like reaction occurring within diverse carcinomas in the absence of therapy appears essential for precise staging and appropriate therapy [2,3]. Sarcoid-like reaction is encountered in up to 14% of subjects with carcinomas. The reaction is engendered by T cell mediated hypersensitivity reaction configuring epithelioid cell granulomas.

Sarcoid-like reaction may concur with infection, various therapies or foreign bodies. Additionally, the reaction may occur with precision targeted and immune checkpoint inhibitor therapy as BRAF and MEK inhibitors [3,4]. Disorders concurrent with sarcoid-like granuloma emerge as carcinoma, toxoplasmosis, fungal infection, tuberculosis, atypical mycobacterial disease, pneumoconiosis, immunocompromised individuals as encountered in Crohn’s disease, primary biliary cirrhosis or Sjogren’s syndrome, extrinsic allergic inflammatory alveolitis (farmer’s lung), anticancer chemotherapy, exposure to chemicals as beryllium, zirconium, silicon, starch granules or pine pollen [3,4].

Sarcoid-like reaction may concur with various malignancies as breast, pulmonary or renal parenchyma. Visceral carcinoma of uterus, breast, pulmonary parenchyma and stomach may induce sarcoid-like reaction. The exceptional extra-thoracic sarcoid-like reaction represents with obscure proportions. However, sarcoid-like reaction within the cutis, hepatic parenchyma, spleen, central nervous system, pancreas, bone or ocular tissue may be encountered [3,4].

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15. Image 1 Courtesy: Science direct.
16. Image 2 Courtesy: The Rheumatologist.