Abstract Merkel cell carcinoma is a rare skin cancer with neuroendocrine differentiation. The risk factors include sun exposure, advanced age, immunosuppression (such as transplant recipients, patients with lymphoproliferative neoplasms, or patients with HIV), and Merkel cell polyomavirus infection. Clinically, Merkel cell carcinoma appears as a cutaneous or subcutaneous plaque or nodule, but this tumor diagnosis is rarely made clinically. Therefore, histopathology and immunohistochemistry are usually necessary. Primary tumors without evidence of metastases are treated with complete surgical excision and appropriate surgical margins. The presence of occult metastasis in a lymph node is frequent and a sentinel lymph node biopsy should be performed. Postoperative adjuvant radiotherapy increases local tumor control. Recently, agents that block the PD-1/PD-L1 pathway have shown objective and durable tumor regression in patients with advanced solid malignancies. The first anti-PD-L1 antibody used in patients with Merkel cell carcinoma was avelumab, but pembrolizumab and nivolumab have also shown efficacy. This article describes the current state of knowledge of the epidemiology, diagnosis, and staging of Merkel cell carcinoma, as well as new strategies for its systemic treatment.

Abstract Vegetative chronic genital herpes is an atypical presentation of herpes simplex 2 that it is usually seen in patients coinfected with human immunodeficiency virus. Clinically, it is characterized by extensive ulcers that evolve to chronification and hypertrophic pseudotumor forms. Antiviral drugs are recommended for the treatment, and acyclovir is the most used one. Foscarnet is the treatment of choice to resistant cases, although treatment failure has been reported. We report a male patient, previously diagnosed with human immunodeficiency virus who developed vegetative chronic genital herpes resistant to acyclovir and successfully treated with imiquimod.