Staged Surgical Resection of Giant Multicentric Cranial Plasma Cell Neoplasms: A Case Report

Calvarial plasma cell neoplasms are uncommon and may present as destructive osteolytic lesions, requiring careful distinction among localized plasmacytoma, multifocal plasmacytoma, and multiple myeloma. We report the case of a 45-year-old male construction worker who presented with a six-month history of a progressively enlarging, painless frontoparietal mass and a second smaller lesion in the left posterior parietal region. Neurological examination was normal. Non-contrast and contrast-enhanced CT demonstrated a large expansile osteolytic lesion centered at the cranial vertex, measuring 101 × 84 × 74 mm, with internal bony spicules, a soft-tissue component, heterogeneous enhancement, and localized mass effect on the adjacent bilateral parietal lobes. A second osteolytic lesion with similar radiological features measured 49 × 41 × 37 mm. Laboratory evaluation revealed elevated serum kappa light chains, an abnormal kappa/lambda ratio, increased IgG levels, and serum immunofixation positive for monoclonal IgG kappa. Because of the large tumor burden, surgical complexity, multicentric calvarial involvement, anticipated operative duration, potential cumulative blood loss, reconstructive planning, and airway considerations related to previous tracheal surgery, staged surgical management was performed. The dominant frontoparietal lesion was resected first through bicoronal exposure and circumferential craniectomy, followed two weeks later by resection of the second lesion and cranioplasty. Histopathological examination of both lesions demonstrated a plasma cell neoplasm, and immunohistochemistry showed CD138-positive plasma cells with kappa light-chain restriction, confirming a clonal plasma cell neoplasm. The patient recovered without neurological deficit and was referred to hematology for systemic staging. This case highlights the importance of considering plasma cell neoplasm in the differential diagnosis of multicentric destructive calvarial masses. It illustrates the potential role of staged surgical resection in selected patients with giant calvarial involvement.