Background: Molluscum contagiosum (MC) causes characteristic cutaneous lesions that occur mainly in children, sexually active adults, and immunocompromised individuals, especially those with human immunodeficiency virus (HIV) infection. Patients infected with HIV, particularly those with advanced disease, have an increased incidence, up to 33.3%, of MC in non-anogenital areas. MC has been rarely found to be associated with epidermoid cysts.
Case report: A 44-year-old male with HIV infection presented with the complaint of a-3-month history of a tender nodule on the left neck. H&E stained sections showed a ruptured cyst, lined with squamous epithelium showing cytopathic changes of MC, and a xanthogranuloma-like inflammatory reaction with characteristic Touton-type giant cells.
Conclusion: MC infections are common, however MC associated with epidermoid cysts is infrequent. A few cases of MC occurring in epidermoid cysts have previously been reported. We are presenting a case of MC involving an epidermoid cyst in an AIDS patient, with a unique xanthogranuloma-like reaction. Xanthogranulomatous (XG) reactions have been infrequently reported in association with other viral infections, however, poxvirus-associated XG reaction has only been observed in animals. This is the first reported case of MC-associated XG reaction in humans.