Reversal of rare paraneoplastic syndromes in melanoma: fever and cutaneous melanosis

Paraneoplastic syndromes (PNS), manifestations of systemic effects of a tumor, are rare in patients with melanoma. We describe two cases of patients who presented with rare PNS, fever, and cutaneous melanosis, that resolved after treatment of melanoma. The first patient, a 64-year-old woman, presented with high fever. After diagnostic evaluation, infectious causes were excluded and the patient was diagnosed with metastatic melanoma. The fever was attributed as a PNS. After surgical removal of a large necrotic intramuscular metastasis in her leg, her fever dissolved completely, allowing continuation of immunotherapy. The second patient, a 76-year-old man, presented with a grayish skin pigmentation and dark urine and referred to the gastroenterologist. He was diagnosed with metastatic melanoma and his symptoms were recognized as cutaneous melanosis. After initiation of immunotherapy, the pigmentation gradually faded. This case series show two distinct and rare paraneoplastic phenomena in melanoma. Early recognition and tailored management of PNS is crucial, as these syndromes may obscure underlying malignancy or influence patient's overall condition. In our cases, PNS resolved after tumor-directed treatment.