Bone regeneration after chemotherapy for vault lymphoma

A 76-year-old woman presented with a mass in the left frontal region of the scalp. On admission, neurological examination found no deficits. CT revealed an osteolytic mass lesion in the left frontal cranial vault. She underwent open biopsy of the subcutaneous lesion. Histological examination identified cells with pleomorphic nuclei and marked nucleoli, and immunohistochemical staining showed these cells were positive for CD20, but negative for CD3. The histological diagnosis was diffuse large B-cell lymphoma. The patient received chemotherapy consisting of rituximab, cyclophosphamide, adriamycin, vincristine and prednisolone. Fluorine-18 fluorodeoxyglucose positron emission tomography demonstrated complete response. Follow-up CT revealed that the tumour had completely disappeared, with regeneration of the destroyed bone. The regenerated skull bone had adequate strength without significant deformity, so cranioplasty was unnecessary. The present case demonstrates the regeneration of destroyed skull bone after chemotherapy for cranial vault lymphoma.