Primary Pulmonary Malignant Melanoma: A Case Report and Literature Review

Abstract

Background: Primary pulmonary malignant melanoma (PMM) is an extremely rare disease entity. There are limited published data on primary pulmonary malignant melanomas. The clinical manifestations and imaging features are non-specific. The imaging features of pulmonary melanoma have been described in previous reports, but it is still challenging to diagnosis it radiologically. Case presentation: A 66 years old male presented with productive cough and back pain. His chest computed tomography (CT) scan revealed homogenous mass with higher density in left hilum with metastatic nodules in lungs. The metastatic lesions in vertebra on magnetic resonance imaging (MRI) were hyper-intense on T1WI and hypointense on T2WI. Further evaluation and immunohistochemical examination confirmed the diagnosis of primary pulmonary malignant melanoma with metastasis to vertebral bodies, liver, adrenal and lungs. He received 2 cycles of chemotherapy and died one month after initial diagnosis of the disease. Conclusion: We have described pulmonary melanoma as bilateral homogenous nodules and mass with a higher computed tomography value. Although CT value has not been described in all literatures, many cases displayed higher density masses. So, clinicians should consider primary lung melanoma as a differential diagnosis for patients with such higher density mass in CT scan and hyper-intensity on T1WI and hypo-intensity on T2WI on MRI.