Temporary noncicatricial focal alopecia following Gamma knife radiosurgery: Case series and review of literature.

OBJECTIVE: The aim of this study is to report the pattern, timing, responsible radiation parameters, and dosimetric results on the outcome of alopecia following gamma knife radiosurgery (GKRS) for various intracranial pathologies. A literature review of radiation-induced alopecia and observation of this complication with GKRS are also included. MATERIALS AND METHODS: The authors report 6 cases of GKRS-induced focal temporary alopecia without dermal fibrosis or clinical scarring and with no long-term squeal. RESULTS: In all the cases, the scalp received ≥3 Gy radiation exposure. Post GKRS alopecia is a temporary, noncicatricial, focal, reversible phenomenon observed within 2 weeks of the treatment. This acute complication is dose-dependent and reflects damage to the hair follicle. It is only seen with treated volumes in the superficial location. Hair regrowth occurs within two months with no long-term complications and change in hair quality being noted. CONCLUSION: Compared to whole brain radiotherapy, chances of alopecia are significantly less after GKRS. Despite a sharp dose fallout, a single fraction high-dose radiosurgery with GKRS may expose the skin appendages to more than 3 Gy radiation exposures, which may injure the hair follicles irrespective of the growth phase (anagen, telogen, or catagen) they are in. A careful planning that includes sparing of the dermal appendages and hair roots up to 4-6 mm depth in the skin may prevent this complication. Patients with superficial lesions should be well informed about the reversible nature of this possible complication, with near-normal hair growth being established within 2 months of treatment.