Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 60 6 2022 07 11 375 381 Masoumeh Roohaninasab Department of Dermatology, Rasool Akram Medical Complex Clinical Research Development Center (RCRDC), Iran University of Medical Sciences, Tehran, Iran. AND Department of Dermatology, Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran. Azadeh Goodarzi Department of Dermatology, Rasool Akram Medical Complex Clinical Research Development Center (RCRDC), Iran University of Medical Sciences, Tehran, Iran. AND Department of Dermatology, Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran. Reza Chalangari Kassir Dermatology, Dallas, Texas, USA Katalin Martits-Chalangari Kassir Dermatology, Dallas, Texas, USA. Nazgol-Sadat Haddadi Experimental Medicine Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Parvin Mansouri Department of Dermatology, Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran 2021 08 02 2021 12 27 Plasmoacanthoma is a rare verrucous tumor classified as a form of reactive plasmacytosis. We present the first reported case of plasmoacanthoma following exposure to bacillus Calmette-Guérin (BCG) and a comprehensive review of the literature to better illustrate the patients’ characteristics and proposed risk factors, clinical features, diagnosis, treatment, and outcome of current reports. A 64-year-old female presented with a perianal hyperkeratotic plaque and diffused inflammatory macerated erosions in the intergluteal cleft and adjacent to the plaque after intravesical BCG immunotherapy. Laboratory studies disclosed systemic abnormalities and local infection or malignancies. Biopsy showed intradermal polyclonal plasma cell infiltration with acanthosis. The lesions were successfully treated with carbon dioxide laser ablation followed by the combination of pulsed dye laser and intralesional corticosteroid. Diagnosis of cutaneous reactive plasmacytosis should be confirmed by excluding the systemic causes of plasmacytosis and malignancies. It responds well to intralesional corticosteroids; however, in severe cases and large sizes, other treatments such as carbon dioxide laser ablation and pulsed dye laser should be considered as a combined therapy. Identification of causative factors is impractical while skin irritants with subsequent inflammation seem to be involved; as in the current report, BCG contact with skin initialized the pathologic process. https://acta.tums.ac.ir/index.php/acta/article/view/9577