Cranial vault lymphoma - A case report and characteristics contributing to a differential diagnosis.

Background: Lymphomas of the cranial vault are rare and are often misdiagnosed preoperatively as presumptive meningioma with extracranial extension. Case Description: A 58-year-old woman was referred and admitted to our department with a rapidly growing subcutaneous mass over the right frontal forehead of 2 months' duration. The mass was approximately 13 cm at its greatest diameter, elevated 3 cm above the contour of the peripheral scalp, and attached to the skull. Neurological examination showed no abnormalities. Skull X-rays and computed tomography showed preserved original skull contour despite the large extra and intracranial tumor components sandwiching the cranial vault. Digital subtraction angiography showed a partial tumor stain with a large avascular area. Our preoperative diagnostic hypothesis was meningioma. We performed a biopsy and histological findings were characteristic of a diffuse large B-cell lymphoma. A very high preoperative level of soluble interleukin-2 receptor (5390 U/mL; received postoperatively) also suggested lymphoma. The patient received chemotherapy but died of disease progression 10 months after the biopsy. Conclusion: Several preoperative features of the present case are clues to the correct diagnostic hypothesis of cranial vault diffuse large B-cell lymphoma rather than meningioma, including a rapidly growing subcutaneous scalp mass, poor vascularization, and limited skull destruction relative to the size of the soft-tissue mass.