We report on three HIV-infected homosexual male patients with atypical manifestations of mollusca contagiosa (MC). Their clinical presentation mimicked sebaceous nevus of Jadassohn, ecthyma and giant condylomata acuminata. HIV-infected patients feature MC with atypical morphology in about two thirds of the cases. The atypical aspects of MC concern the localization, morphology, growth pattern and size of the lesions. MC is a late manifestation of HIV infection and mirrors marked cellular immune deficiency. We conclude that in HIV-infected patients all tumorous lesions should be biopsied because the clinical characteristics are often not specific enough for a definite diagnosis.