Diagnosis and Management of Sarcoidosis-like Reaction in Adjuvant Immunotherapy: A Comprehensive Review and Clinical Implications

Immune checkpoint inhibitors (ICIs) have transformed oncologic care and are increasingly used as adjuvant therapy to reduce the risk of recurrence. However, this shift has introduced immune-related adverse events (irAEs) to patients who may otherwise be clinically disease-free after definitive therapy. Sarcoidosis-like reaction (SLR) is an uncommon but important irAE characterized by non-necrotizing granulomatous inflammation. In the adjuvant setting, SLR is uniquely consequential because it can closely mimic recurrent malignancy on surveillance imaging and thereby prompt unnecessary diagnostic procedures, treatment interruption, or escalation of care. This review summarizes the current evidence on ICI-associated SLR with an emphasis on adjuvant immunotherapy, where practical guidance remains limited. We integrate evidence from clinical trials, real-world cohorts, and published case series to summarize the reported incidence of SLR, proposed immunologic mechanisms, clinical and radiographic presentation, pathology, differential diagnosis, and management. Particular attention is given to the problem of distinguishing SLR from recurrence, when tissue confirmation should be prioritized, and how management should be individualized according to clinical severity and organ involvement. Common radiographic features include bilateral mediastinal and hilar lymphadenopathy and pulmonary nodules, but tissue confirmation remains the diagnostic gold standard when feasible. Many cases are low grade and may be managed conservatively. Greater recognition of ICI-associated SLR is critical to avoid misdiagnosis and unnecessary escalation of care while preserving the therapeutic benefit of adjuvant immunotherapy.