Stereotactic Radiosurgery for Localized Cranial Langerhans Cell Histiocytosis: A Single Institution Experience

Introduction: Langerhans cell histiocytosis (LCH) is a rare idiopathic disease, which is characterized by the clonal proliferation of Langerhans histiocytes in various parts of the body and which can lead to organ damage and tumor formation. Reports of cranial LCH in the adult population are extremely rare. Although surgery remains the preferred option for localized LCH lesions, the role of stereotactic radiosurgery (SRS) is emerging.

Methods: To retrospectively review a rare case series to determine the safety and effectiveness of SRS for patients with localized cranial LCH, we retrospectively reviewed histopathologically-confirmed cases of localized cranial LCH treated with SRS at our institute in the adult population between January 2005 and September 2022. Five patients were identified with a median age was 34 years (19-54 years). The tumor location was the pituitary stalk in 3 patients, the orbit in one patient, and the parietal skull in one patient. The median target volume was 2.8 cc (range: 0.37-6.11). The median margin dose was 8 Gy (range: 7-10) and the median isodose line was 80% (range: 67-88). The median follow-up was 139 months (range: 46-207). None of the patients required craniotomy for tumor debulking before or after SRS.

Results: The local tumor control rate for the lesions by end of the follow-up was 100%. All three patients with the LCH in the pituitary stalk had diabetes insipidus at the initial presentation and developed panhypopituitarism after SRS. The other two patients presented no adverse radiation effects.

Conclusion : SRS for patients with localized cranial LCH was a safe and effective treatment modality in this case series. Larger studies are encouraged to validate the role of SRS in the treatment of localized cranial LCH.