Generalized eruptive keratoacanthoma: a diagnostic and therapeutic challenge

Generalized eruptive keratoacanthoma (GEKA) is an extremely rare variant of keratoacanthoma that poses significant diagnostic and therapeutic challenges.

The study included three patients presenting with highly pruritic, generalized eruption of numerous small skin and flesh-colored follicular papules. They were mainly distributed on the face, neck, and trunk. Few larger nodules were also present. Mask-like facies, mucosal involvement, and ectropion were evident in two patients. Family history was irrelevant, and general examination was unremarkable.

Histopathological examination revealed typical features of keratoacanthoma, particularly in the larger lesions. Routine laboratory tests were normal, and ultrasonography and computed tomography revealed no evidence of malignancy. Based on the clinicopathological correlation, the diagnosis of our cases was GEKA of Grzybowski. Acitretin 1 mg/kg per day and methotrexate 15 mg/week for three months were associated with mild or no response. Cyclophosphamide pulse therapy 1 g/month for six months was associated with complete clearance of the lesions in the first two patients, while the third was lost to follow-up after failure of acitretin therapy.

Because of the extreme rarity of reported cases, the common absence of classic large lesions of keratoacanthoma, the atypical histological presentations in some cases, and absence of a uniformly effective therapeutic approach, we believe that GEKA still represents a diagnostic and therapeutic challenge. Cyclophosphamide pulse therapy is a promising alternative to oral retinoids.