Grover disease, or transient acantholytic dermatosis, is a benign acquired dermatosis whose diagnosis can be challenging due to the variability of its clinical and histopathological manifestations and its resemblance to other acantholytic dermatoses. It has gained particular relevance in oncologic patients, in whom it may present idiopathically or in association with radiotherapy and other antineoplastic treatments.

We report the case of an 83-year-old man with a history of prostate cancer treated with radiotherapy 16 years earlier, who presented with a 3-month history of a chronic, asymptomatic dermatosis involving the chest, abdomen, and left arm, characterized by erythematous plaques with thick scales and surrounding pustules. Given the lack of response to initial treatment with oral prednisone and minocycline, as well as the persistence of the lesions despite tapering doses of systemic corticosteroids, two incisional biopsies were performed. Histopathologic examination revealed an acanthotic, hyperkeratotic epidermis with suprabasal acantholytic clefts and dyskeratotic keratinocytes, including corps ronds and grains, findings consistent with Grover disease.

The patient achieved sustained clinical control following gradual tapering of oral corticosteroids and transition to a combined topical regimen consisting of a corticosteroid, calcipotriol, emollients, and keratolytics. Progressive improvement was observed, with no new lesions after one month of follow-up, although complete resolution was not achieved.

This case highlights the importance of clinicopathologic correlation in the diagnosis of Grover disease in older patients with a history of malignancy, as well as the potential to achieve clinical control with topical therapy alone, thereby minimizing exposure to systemic corticosteroids in this age group.