Abstract

The introduction of immune checkpoint and BRAF/MEK inhibitors has revolutionized the treatment for advanced melanoma. While these agents have led to improvement in survival, they may be associated with adverse side effects, including drug-induced sarcoidal granulomatous reactions (SGRs). We report two such cases. The first is a 63-year-old male with initial stage IIA melanoma treated with wide local excision (WLE) who developed BRAF-mutated oligometastatic pulmonary disease status post resection and was initiated of dabrafenib and trametinib. Eight months later, a PET scan showed symmetric bilateral diffuse lymphadenopathy and cutaneous lesions in the extremities concerning for disease progression or a lymphoproliferative malignancy. An inguinal lymph node biopsy showed non-caseating granulomatous inflammation with negative microbial stains consistent with a drug-induced SGR. A second case involved an 80-year-old male with initial stage IB melanoma treated with WLE who subsequently developed a left axillary lymph node metastasis and was started on nivolumab and ipilimumab. A few months later, he developed anterior uveitis, parotitis and many small, pink indurated papules on the trunk, extremities and face concerning for metastatic melanoma. A skin biopsy was consistent with a drug-induced SGR. An interesting finding in this case was the presence of rare melanocytes in the dermis admixed with the granulomatous inflammation, which may represent a resolving melanoma metastasis or regression of a benign melanocytic lesion. Our cases highlight the importance of recognizing SGRs as an adverse reaction to targeted therapy as they may mimic disease progression or lymphoproliferative disorders.

Financial Disclosure:
No current or relevant financial relationships exist.