Melanoma Masquerading as a Zosteriform Rash.

BACKGROUND Primary care physicians and internal medicine specialists frequently encounter a variety of rashes. Many of these cases look and feel typical of common entities, resulting in the potential for misdiagnosis. CASE REPORT This is a case of a zosteriform rash where the surprising true diagnosis of metastatic melanoma was confirmed with bedside skin punch biopsy. Possible mechanisms involve direct cutaneous injury, neuronal, and dorsal root ganglia involvement in metastases. CONCLUSIONS Skin biopsy is indispensable especially when there is a lack of clinical response or deterioration in the clinical condition. The pathophysiology of zosteriform metastasis is unclear.