Characteristics of cranial vault lymphoma from a systematic review of the literature

Highly Radiosensitive Diffuse Large B-cell Lymphoma of the Skull Treated With Low-Dose CyberKnife Radiotherapy: A Case Report

Diffuse large B-cell lymphoma (DLBCL) of the skull is rare, and there are no reports of treatment using CyberKnife (CK). Here, we report the case of a patient with skull DLBCL treated with low-dose CK radiotherapy (CKR), resulting in effective local control. The patient was a 75-year-old man who was initially diagnosed with multiple skull metastases (frontal, occipital, right orbital bones) from renal pelvic cancer. We initially created a CKR treatment plan for the frontal bone lesion with a marginal dose of 35 Gy and a maximum of 64.8 Gy in five fractions every other day. Because the frontal bone lesion shrank rapidly from the start of the treatment, we completed CKR with a marginal dose of 21 Gy and a maximum of 38.9 Gy in three fractions over five days. At six weeks after CKR, the MRI showed complete resolution of not only the frontal bone lesion but also the occipital and orbital bone lesions that we did not directly target for irradiation. The maximum doses irradiated to the occipital and orbital bone lesions were 0.31 Gy and 0.34 Gy. Because of the marked shrinkage of the skull lesions, we suspected that the patient had a radiosensitive neoplastic disease. FDG-PET/CT revealed multiple lymph nodes and bone metastases. The patient underwent a scrotal biopsy, and the histologic diagnosis was DLBCL. The patient subsequently received chemotherapy for DLBCL. Ten months after CKR and six months after the start of chemotherapy for DLBCL, the patient died due to gastrointestinal bleeding. The skull lesions were well-controlled locally without adverse events due to CKR until the end of the life. Our present case suggests the importance of diagnosis and the effectiveness of low-dose CKR in the skull DLBCL.

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.