International Journal of Clinical & Medical Images

An 89-year-old woman with a resistant treatment of herpes zoster was brought to the emergency for a painful scalp rash lesions evolving for one month. Clinical examination showed erosive and crusted lesions with purulent discharge lay within the area supplied by the ophthalmic branch of the right trigeminal nerve (Figure 1A). Palpation revealed a prominent homolateral 3 cm cervical lymph node. Given the recent history of possible herpes zoster with secondary infection antibacterial treatment was given with a check-up after 48 hours. She showed up 2 month later with impressive red nodular and papular lesions extending to the left hemiscalp (Figure 1B). No history of removed pigmented nevus was obtained. The rest of the cutaneous and mucosal examination was negative. A nodule biopsy showed metastatic malignant melanoma. The patient refused all the assessment for the staging of this zosteriform metastatic melanoma of unknown primary. She died unfortunately 3 weeks later. Clinically cutaneous metastatic disease could take a wide morphological spectrum including erythematous patches or plaques, inflammatory erysipela-like lesions, diffuse sclerodermiform lesions with induration of the skin (en cuirasse), telangiectatic papulovesicles, purpuric plaques mimicking vasculitis, and alopecia areata-like scalp lesions. Zosteriform metastasis is painful, tender or pruritic consists of vesicles on a background of erythema and limited to a single unilateral dermatome; that may lead misdiagnosis. Our patient was initially misdiagnosed as herpes zoster. Several hypotheses have been made to explain the pathogenesis.  For example, a recent herpes zoster might lead to the infiltration of malignant cells in a Koebner-like phenomenon; perineural lymphatic spread of malignant cells has been suggested also but the exact etiology remains unclear. To our better knowledge this is the first publication of zosteriform metastasis from unknow primary melanoma of the scalp with a rapidly progressive evolution. Due to the rarity of metastatic melanoma in the form of zoster-like lesions, clinicians should consider this form of cutaneous involvement in the differential diagnosis of zosteriform lesions to avoid inappropriate medical care.