Alopecic and Aseptic Nodules of the Scalp/Pseudocyst of the Scalp: Clinicopathological and Therapeutic Analyses in 11 Korean Patients

Background: Alopecic and aseptic nodule of the scalp (AANS) is a rare disease entity first reported in 1992 as pseudocyst of the scalp (PCS). Controversy exists regarding the histopathology and etiology of reported cases. Objective: We performed this study to analyze the clinical and histopathologic features of AANS/PCS in Korean patients. Methods: A retrospective review of medical records from 2008 to 2013 at Inje University Busan Paik Hospital was performed. Results: Eleven patients were enrolled. All patients were male, and their mean age was 21.6 years. Most patients had a solitary nodule (10/11) located predominantly on the vertex. The mean nodule size was 20 mm. Inflammatory cell infiltration in the deep dermis was a histologic feature of AANS/PCS. Eight patients showed granulomatous infiltration. All patients were treated with short-term antibiotics and intralesional steroid injection. Conclusion: Our results suggest that dermatologists should consider AANS when diagnosing an alopecic nodule on the scalp.