Abstract

A 52-year-old female with a history of pemphigus vulgaris involving the scalp and trunk presented with a painful, hyperkeratotic lesion on the right mid-back. She denied a history of non-melanoma skin cancer. Prior treatments for her pemphigus included prednisone, mycophenolate mofetil, rituximab, and intravenous immune globulin (IVIG). At the time of presentation, the patient had no active blisters and had been off all systemic therapies completely for 4 months. She was using only topical fluocinolone oil to the scalp and clobetasol to the body. Physical exam showed an isolated 1.8cm x 1.1cm hyperkeratotic plaque. Histology showed hyperkeratosis, acanthosis, and acantholysis extending down a hair follicle, consistent with post-pemphigus acanthoma. A post-pemphigus acanthoma typically presents as a verrucous lesion at the site of a previous pemphigus blister and can occur in individuals with clinical remission of pemphigus vulgaris or pemphigus foliaceus [1]. Some view this entity as a hyperkeratotic variant of pemphigus vulgaris. Post-pemphigus acanthomata show immunofluorescent activity, indicating the need for close clinical observation and potential treatment intervention to prevent progression to overt pemphigus. To date, only two peer reviewed articles have discussed the notion of post pemphigus acanthomata. A case series by Yesudian et al. identified 47 cases of pemphigus vulgaris and 5 cases of pemphigus foliaceus, out of which thirteen developed acanthomata as part of the healing process [1]. Of note, two of these included positive immunofluorescence studies showing intercellular fluorescence. In contrast, a case report by Ohashi et al reported similar recalcitrant lesions on the trunk of a patient with pemphigus foliaceus being treated with prednisolone, IVIG, plasma exchange and cyclosporine [2].

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