Sonographic diagnosis of unifocal Langerhans cell histiocytosis of the skull

Abstract

Langerhans cell histiocytosis (LCH) is a neoplastic disease characterized by the idiopathic proliferation of Langerhans cells. X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) are often performed, and pathology should be identified for a definitive diagnosis. Single-system single-site lesions can be treated by surgical excision, but multi-system and single-system multi-site lesions are challenging to treat by surgical excision alone; therefore, chemotherapy is used after definitive diagnosis through biopsy. We report a single-system multi-site LCH of the skull that was safely biopsied using preoperative ultrasound evaluation. A 2-year-old girl was referred to our hospital with suspected LCH on CT to evaluate a head contusion. A biopsy was conducted for a definite diagnosis, and chemotherapy was administered because of multi-site lesions. To ensure a safe biopsy, preoperative ultrasonography was performed to evaluate the relationship between tumors and the dura mater, venous sinus, and blood flow inside tumors. The pathology was divided into bone lesion, the part of temporalis muscle in contact with the bone lesion, muscle belly of temporalis muscle directly above the bone lesion, and capsular tendon membrane. Langerhans cells were present only in bone lesions. Preoperative sonographic diagnosis is helpful for Langerhans cell histiocytosis. Additionally, a biopsy should be performed on the tumor, not the surrounding tissue.