Solitary plasmacytoma of the calvarium: A successful management of a long-standing large lesion with a long-term follow-up.

Background: Solitary plasmacytoma of the calvarium (SPC), without evidence of multiple myeloma (MM), is extremely rare. We report a case of a long-standing large SPC that was treated successfully by surgical excision and adjuvant radiotherapy with a long follow-up period. Case Description: A 58-year-old male patient presented with a 5-year history of painless skull swelling. On the physical examination, the mass was 6 × 6 cm in size, oval, not tender, and firm in consistency with normal skin color. A brain computed tomography scan showed a destructive skull lesion. A brain magnetic reasoning imaging (MRI) showed a large expansile lytic mass lesion arising from the skull vault in the frontal-parietal region with multiple internal septa. The patient underwent a craniectomy and excision of the lesion, followed by cranioplasty using methyl methacrylate. The final diagnosis was consistent with plasmacytoma based on the histopathological features. One month follow-up brain MRI showed no evidence of residual tumor. The skeletal survey and bone marrow biopsy did not reveal any evidence of MM. The patient was referred to medical oncology for further treatment and received radiation therapy. During nine years of clinical and radiological follow-up, there was no evidence of any metastasis or recurrence. Conclusion: SPC is a rare disease with high rates of misdiagnosis. Careful evaluations are crucial to exclude systemic involvement. Surgical resection followed by radiotherapy may be adequate for the disease control. Close follow-up with regular lifelong examinations is important to avoid a generalized incurable disease.