<prompt> Koenens tumor are seen in ?NeurofibromatosisTuberous sclerosisStruge weber syndromeTuberculosis  <response>: Koenen tumors, or periungual and subungual fibromas, are a benign, cutaneous manifestation of tuberous sclerosis. They are disfiguring, painful, and challenging to treat as they frequently recur . Koenens tumor is a cutaneous condition that results in fifty percent of tuberous sclerosis cases. Ref - Davidson 23rd edition pg 838 