Perianal ulcer and diabetes insipidus: A rare presentation of langerhans cell histiocytosis in an adult male

Langerhans cell histiocytosis (LCH), previously known as Histiocystosis X, is a rare idiopathic disease caused by a build-up of langerhan cells in the body. LCH has a heterogenous form of clinical presentation and presents with varying degree of severity. The severity often depends on the disease burden. LCH can manifest as a unifocal disease, multifocal-unisystem or multifocal-multisystem disease with the latter being more fatal than the rest. Risk organ involvement confers a grim prognosis. Perianal lesions are extremely rare skin manifestation of LCH with only few cases reported in the past. Vinca-alkaloids and steroid therapy have been shown to be effective in a large percentage of those presenting with LCH. This case report highlights the diagnosis and management of LCH presenting as a painful perianal ulcer in the background of newly diagnosed diabetes insipidus.