Dark sputum: An atypical presentation of primary pulmonary malignant melanoma

Abstract

Primary melanoma of the lung is an extremely rare clinical entity. We found only 32 cases reported in literature, and in two of these multiple brain metastases were present. We describe a case of primary lung melanoma with brain and skin metastases that presented with an initial clinical diagnosis of pneumonia. A 55-year-old white man presented with cough productive of dark sputum and fever. A chest x-ray showed a right lung infiltration. After failure to respond to usual treatment for pneumonia, bronchoscopy examination and CT scan revealed a right pulmonary mass. The CT-guided biopsy confirmed a diagnosis of malignant melanoma. The primary lung origin of the tumor was demonstrated by the characteristic junctional pattern of melanoma cells. Further evaluation revealed metastases in the brain and in skin. Primary lung melanoma is an uncommon neoplasm that may be confused with more conventional types of lung cancer. Careful interpretation of histopathological information in correlation with all other clinical, laboratory and imaging studies may be needed to establish a diagnosis. Evaluation for metastases should include looking at the eyes, brain, skin. Due to the small number of cases reported in literature, there is no experience on the management and the prognosis of the disease.

Keywords

• Primary lung melanoma
• Malignant melanoma