Pseudocyst of the scalp, also called aseptic nodules of the scalp, represents less known entity first described by Iwata in 1992.
A 26-years-old male patient was consulted for two alopecic pseudocystic lesions, slightly painful on palpation, located on the scalp that occurred 6 months ago. Histological examination revealed a pseudocystic appearance. Surgical excision of lesions was performed.
Pseudocyst of the scalp usually occur in men aged between 18 and 40 years. Clinical appear as single or two alopecic pseudocystic nodules, most often asymptomatic but sometimes may present transient inflammatory phases, localized at the vertex and upper occipital region of the scalp. Incision of nodules reveals a citrine or purulent, sterile fluid. Histological analysis shows a pseudocyst without any wall associated with perilesional inflammatory granuloma. The main differential diagnosis is dissecting cellulitis of the scalp compared with pseudocyst of the scalp has a better prognosis.Treatment consists of surgical excision, doxycycline or intralesional injections of triamcinolone.