Hidroacanthoma simplex (HS) is a rare benign intraepidermal tumor that originates in the acrosyringial portion of the eccrine duct. Clinically, they are well-defined lesions, flat or verrucous brownish plaque, and can be misdiagnosed with other types of benign or malignant tumors. Dermoscopy reveals small black globules and fine scales. The histopathology of HS is characterized by typical intraepidermal nests, well-circumscribed, composed of uniform basaloid and poroid cells within the acanthotic epidermis with cystic or ductal structures in the nests. We report a case of HS that changes its clinical appearance, dermoscopy, and histopathologic findings over time. Differential diagnoses included seborrheic keratosis, Bowen disease, melanoma, and malignant HS.

Apresentamos um caso de arterite de células gigantes com amaurose, seguida de necrose da língua, diagnosticado clinicamente com boa resposta terapêutica ao corticoide oral. Salientamos que os casos de necrose da língua são extremamente raros. A suspeita diagnóstica de arterite de células gigantes é de fundamental importância e mesmo na impossibilidade de realizar a biópsia de artéria temporal, não se deve retardar o início do tratamento sob pena de acarretar sequelas definitivas ou manifestações mais graves da doença.