A case of Langerhans cell histiocytosis of the skull in which preoperative methionine positron emission tomography was useful in comprehending the spreading of the lesion

BACKGROUND: The problem with treatments against skull lesions of Langerhans cell histiocytosis (LCH) is that invasions often reach the bones and dura mater, making it difficult to accurately comprehend the range thereof prior to surgery. We herein report that (11)C-methionine positron emission tomography (PET) (Met-PET) carried out prior to surgery was useful in comprehending the spreading of the lesion. CASE DESCRIPTION: A 20-year-old female presented with swelling and dull pain on the left side of the head. A slightly heterogeneously reinforced tumor was observed inside the bone defect in the gadolinium-enhanced T1-wighted image upon magnetic resonance imaging (MRI) and the dura mater contacting the tumor was observed with an enhancing effect. Accumulation was poor in the center of the tumor upon Met-PET, and accumulation with a well-defined border was observed in the border thereof as well as the area adjacent to the brain. Surgical resection was performed; the pathological diagnosis was LCH. An invasion of tumor cells was observed in the dura mater with accumulation observed according to Met-PET. Moreover, the accumulation of tumor cells was observed in the area observed with accumulation inside the bone; however, the center part with poor accumulation lacked tumor cells, with fibrous tissue accounting for most parts. CONCLUSION: Met-PET was believed to be helpful in comprehending the spreading of the tumor in the surroundings of the brain surface for skull lesions.