Spontaneous Regression of Cranial Vault Lymphoma: A Case Report.

Primary lymphoma of the cranial vault is extremely rare and often mimics other cranial bone tumors on imaging. We report a 75-year-old female with a scalp mass and occasional headache. MRI revealed a lesion centered in the cranial vault, extending both intra- and extracranially. The initial diagnosis was intraosseous meningioma, but the lesion rapidly decreased in size over a few weeks without any treatment. Biopsy revealed histology consistent with non-Hodgkin lymphoma. Further classification suggested marginal zone B-cell lymphoma, a rare entity arising in the cranial vault. We managed the patient with imaging follow-up and found no recurrence for six months. The present case supports the notion that indolent lymphomas arising in the cranial bone share regression potential seen in other tissues. Accurate diagnosis requires histopathological confirmation even when lesions regress spontaneously. A watch-and-wait approach may be reasonable for selected cases, with careful monitoring for progression or transformation.