Mycobacterium mimicking metastatic melanoma.

We present three patients with lung nodules with an antecedent history of primary cutaneous melanoma or metastasis of melanoma to extrathoracic lymph nodes. Based on radiological findings, it was suspected that these patients had metastatic disease. Subsequent investigations confirmed the cause of the nodules was non-tuberculous mycobacterial infection. We discuss the similarities in symptoms and radiological features between atypical mycobacterial infections and metastatic disease and why a biopsy is important prior to planning a patient's treatment.