Primary pulmonary malignant melanoma with multiple metastases: a case report and literature review

Primary malignant melanoma of lung (PMML) are relatively rare, accounting for about 0.4 % of all malignant melanomas and only 0.01 % of all lung tumors, and PMML with distant metastases found at diagnosis is extremely rare. A case of PMML presented as multiple solid and ground glass pulmonary nodules with brain, liver,intrapulmonary and lymph nodes metastasis was reported in this study. A 42-year-old man had a headache for 10 days after symptomatic treatment in the department of neurology in our hospital, but the above symptoms did not improved. Multiple nodules were considered by head MRI. Chest CT showed two solid nodules in the upper and lower lobes of the right lung and multiple ground glass nodules in both lungs. To further clarify the diagnosis,CT-guided percutaneous puncture biopsy of pulmonary nodule was performed. The pathology revealed malignant melanoma of <lung>.NRAS + BRAF gene test, showing BRAF gene exon 15 V600E mutation Dalafenib and trametinib were given targeted therapy after discharge. After 1 month follow-up, all lesions were significantly decreased. PMML presenting as solid and ground glass pulmonary nodules with multiple metastases is extremely rare. The early identification of pathological biopsy and genetic testing is crucial for precise treatment and enhancing prognosis.