Pseudoangiomatous Stromal Hyperplasia Presenting as Rapidly Growing Bilateral Breast Enlargement Refractory to Surgical Excision.

According to a review of the literature, it is very rare for epidermal inclusion cysts to occur in the joint. Strauchen and Strefling [4] reported a case of an epidermal inclusion cyst occurring after arthroscopic surgery in the knee joint. However, this case occurred in the knee joint. To the best of our knowledge, no cases of epidermal inclusion cysts occurring in the interphalangeal joint have been described. In the current case, the patient had a past history of trauma and developed the epidermal inclusion cyst at the site of the trauma. It can therefore be inferred that it is very unlikely for epidermal inclusion cysts to occur as congenital lesions. Based on other cases of epidermal inclusion cysts arising due to trauma, it is very likely that epidermal inclusion cysts in joints occur as a result of the squamous cells forming the epidermis being directly invaginated into the joint due to the trauma, or due to the invasion of a preexisting epidermal inclusion cyst into the joint [5]. Still, little is known about the exact pathophysiology underlying the intra-articular presence of epidermal inclusion cysts, which deserves further study. In conclusion, our case highlights the possibility that epidermal inclusion cysts might also occur, albeit rarely, in the interphalangeal joints of the fingers. Recognizing this may be essential for avoiding unnecessary operations and amputations of fingers. Finally, we propose that masses found in the fingers should undergo histopathological examination in order to ensure that epidermal inclusion cysts are Fig. 3. After six months, no evidence of recurrence was present in a simple postoperative radiograph.