[Generalized eruptive histiocytoma]

We present the case of a 64-year-old male who developed multiple asymptomatic papules over a four-month period, distributed symmetrically on the trunk and proximal regions of the limbs, while the scalp, palms, soles and mucous membranes were spared. The lesions were discrete papules, brownish-erythematous, rounded, ranging from slightly raised to hemispherical, from 1 to 3 mm in diameter and firm to the touch. Clinical, histopathological, immunohistochemical and ultrastructural studies were consistent with generalized eruptive histiocytoma. Laboratory tests and radiological studies did not show any abnormal findings. After being subjected to photochemotherapy, the lesions regressed, but later on new outbreaks of papules appeared. Generalized eruptive histiocytoma belongs to a spectrum of diseases that may overlap; some may even develop into others. As the disease may progress into a more serious ailment, regular checkups with clinical, histological and immunohistochemical examinations should definitely be considered.