RESUMO
BACKGROUND Melanoma is an aggressive skin cancer that can be difficult to manage. Its treatment has been transformed by immunotherapy. Melanoma cells frequently have mutations that make them vulnerable to attack by the immune system, and this is how immunotherapy can fight this cancer. Immunotherapy with checkpoint inhibitors targets mechanisms that malignant cells use to evade immune system detection, blocking proteins produced by the tumor, and allowing the immune system to identify and attack cancerous cells. CASE REPORT A 74-year-old woman presented with a lump on the right side of her chest. Tests revealed a metastatic malignant tumor with melanocytic differentiation. Stage IV melanoma was diagnosed, and the patient started therapy with nivolumab/ipilimumab for palliative intent, which she tolerated without adverse effects. However, she was hospitalized for Clostridioides difficile colitis after 3 treatment cycles, and computed tomography (CT) scan findings suggested disease progression. Positron emission tomography (PET)-CT obtained after her discharge from the hospital showed a complete metabolic response at all disease sites, indicating the initial progression was most likely a pseudo-progression from the use of immunotherapy. The patient continued with nivolumab as a single agent and has been doing well. CONCLUSIONS This case highlights the importance of careful evaluation of immunotherapy response in patients with melanoma. The initial progression noted in this patient was most likely pseudo-progression, which resolved with further immunotherapy. Clinicians should consider PET-CT imaging in cases of suspected pseudo-progression to avoid unnecessary changes in therapy. Patient response to immunotherapy demonstrates the effectiveness of immunotherapy in treating advanced melanoma.