Background: Solitary bone plasmacytoma is an uncommon neoplasm derived from clonal plasma cells, representing <5% of plasma cell dyscrasias. Its occurrence in the skull is rare, and involvement of the occipital bone is exceptionally unusual. Such lesions often present as slow-growing, osteolytic masses that may mimic more common cranial tumors on imaging studies, leading to diagnostic challenges. Case Description: A 65-year-old female presented with a painful mass in the occipital region of the skull, with a 2-year evolution. Magnetic resonance imaging (MRI) initially showed a 9.3 × 4.6 × 9.5 cm lesion causing occipital bone destruction and compression of posterior fossa structures, suggestive of meningioma. Bone scintigraphy revealed no evidence of additional lesions. Surgical biopsy was deferred at that time due to the patient’s refusal. Two years later, the patient re-presented with anemia and consented to surgery. Repeat MRI demonstrated a markedly enlarged lesion measuring 18.7 × 16.0 × 12.2 cm, with cystic spaces, intense contrast enhancement, and marked vascularity. Computed tomography confirmed extensive osteolytic destruction of the occipital bone. Histopathological examination showed a proteinaceous background with scattered plasmacytoid cells featuring eccentric nuclei and moderately eosinophilic cytoplasm, consistent with a diagnosis of solitary bone plasmacytoma. Conclusion: Occipital bone plasmacytoma is a rare presentation that may clinically and radiologically resemble meningioma. Accurate diagnosis relies on histopathological evaluation. A comprehensive systemic assessment is essential to exclude multiple myeloma, and appropriate treatment and follow-up are required to prevent progression and recurrence.
Galván et al. (2026) studied this question.