When Bone Grows Beyond Its Bounds: A Giant Exophytic Parieto-Occipital Osteoma - Case Report and Review of the Literature
Iroegbu-Emeruem LU* and Akaa CU3
ABSTRACT
Background: Osteomas are benign, slow-growing, bone-forming neoplasms. Lesions exceeding 30 mm in maximum diameter, or exceeding 110g in mass, are conventionally classified as “giant”, and those involving the cranial vault are exceptionally uncommon. We report a case of a massive exophytic parietooccipital osteoma of extraordinary dimensions that, to our knowledge, ranks among the largest reported in the world literature.
Case Presentation: A 24-year-old woman presented with a slowly enlarging, painless, hard mass over the posterior cranium of more than ten years duration. Clinical examination revealed a massive, firm, non-tender, bosselated swelling occupying the parieto-occipital region, measuring 13 × 12 × 11.5 cm. Computed tomography (CT) of the head confirmed a densely sclerotic, ivory-type exostosis arising from the outer table of the calvarium without intracranial extension. The lesion was excised en bloc under general anaesthesia via a midline posterior craniectomy approach; intraoperative weight of the specimen was ~1800g. Histopathology confirmed a compact (ivory) osteoma. The patient made an uneventful recovery.
Conclusion: Giant calvarial osteomas, though histologically benign, pose significant surgical challenges due to their size, vascularity, and proximity tomajor dural sinuses. Complete surgical excision remains the definitive treatment. Our case exemplifies the importance of thorough preoperative planning, meticulous haemostatic technique, and multidisciplinary perioperative care in the management of extreme-sized skull osteomas.
