Alopecic and Aseptic Nodules of the Scalp (Pseudocyst of the Scalp): A Prospective Clinicopathological Study of 15 Cases

Abstract

Background: Alopecic and aseptic nodules of the scalp (AANS) is a new entity reported first in Japan as ‘pseudocyst of the scalp’. Only retrospective studies have been published. Objectives: To describe the clinicopathological features of AANS (pseudocyst), to evaluate the response to doxycycline and to compare the results to those obtained from patients with dissecting cellulitis of the scalp (DCS). Methods: Fifteen patients with AANS and 7 with DCS were prospectively included. A puncture and a biopsy were made. Patients were treated with doxycycline (100 mg/day) for 3 months. Results: AANS affects predominantly young (mean age 29.7 years), Caucasian (11/15), male (14/15) patients. The main location of the nodules was the occiput. The associated alopecia was nonscarring. Material from the puncture was aseptic. The histopathology showed a deep granuloma in 7 of 14 patients and a nonspecific inflammation in 7 patients. After 3 months, 8 patients were cured and 3 had a good response. Conclusions: The singular aspect of the nodules, the nonscarring alopecia, the deep inflammatory infiltrate and the efficacy of doxycycline confer specificity to AANS.

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

“…Pseudocyst formation was always found in PCS but not in AANS, although granulomatous infiltration was found in both [1,5]. Pseudocyst formation was found in only 4 patients in this study, which is contrary to the previous assumption that racial differences affect pseudocyst formation [5].…”

“…The mean disease duration was longer in patients with than without pseudocyst formation in this study (median, 10.3 and 6.4 months, respectively), which might partially explain the inconsistency in the formation of pseudocysts. PCS was reported to occur between the top and forehead area of the scalp [1], whereas other studies showed lesions on the vertex and upper occipital area [2,5,7]. The most commonly involved site in this study was similar to that of AANS rather than PCS.…”

“…Previous reports regarding PCS and AANS described the clinical characteristics of both as solitary or a few dome-shaped nodules of the scalp with nonscarring alopecia [5]. Both showed a male predilection, especially in young adults [1,2,5].…”

“…Both showed a male predilection, especially in young adults [1,2,5]. Puncture might be positive in both; however, the punctured material was always sterile.…”

“…The consistency of the nodule was firm or fluctuated. In addition, surgical or medical treatment showed a good response and resulted in complete resolution of nodules and alopecia in most cases [1,5,6]. …”