Benign osteoblastoma of the occipital bone: Case report and literature review

Abstract

We present a case of benign osteoblastoma of the occipital bone. Benign osteoblastoma is an uncommon primary bone tumor, which usually involves the vertebrae and the long bones. This tumor rarely develops in the calvaria, showing a preference for the temporal and frontal bones when it does. To the best of our knowledge, this case is only the eighth reported case of benign osteoblastoma confined to the occipital bone. A 20-year-old male presented with a mild tender mass lesion of the occipital area, just below the lambda. Plain X-ray films and CT scans demonstrated an osteolytic mass surrounded by the sclerotic rim within the diploic space. MRI proved to be effective for the evaluation of the intracranial and intraosseous extensions of the tumor. However, it was very difficult to formulate a differential diagnosis against other osteoblastic tumors, or osteoid osteoma, in view of its radiological appearance. The final diagnosis was obtained by careful consideration of the histopathological characteristics of the tumor combined with its clinical and radiological features. Although generally regarded as benign, a complete resection is preferred over conventional curettage as this can guard against possible recurrence and malignant transformation.

Large Osteolytic Skull Tumor Presenting as a Small Subcutaneous Scalp Lesion

“…1 Common benign bone tumors include osteochondromas, giant cell tumors, aneurysmal bone cysts, osteoblastomas, fibrous dysplasia, fibromas, simple bone cysts, hemangiomas, intraosseous meningiomas, and eosinophilic granulomas. [6][7][8][9] The first four have the potential to behave aggressively, and osteochondromas and giant cell tumors have the potential to recur 7,9 or result in pul- monary metastases. 3,10,11 The more common primary malignant bone tumors of the skull include Ewing's sarcoma, osteosarcoma, leukemia, and multiple myeloma.…”

Massive Benign Osteoblastoma of the Suboccipital Bone and Foramen Magnum Region

“…It involved the suboccipital bone extending from the torcula till the foramen magnum region without the involvement of occipital condyles and the atlas. MRI characteristics show low and intermediate signal intensity on T 1 -weighted images, and low or high signal intensity on T 2 -weighted images [12,13,14]. The altered intensity seen on MRI denotes either reactive bone formation or inflammation which requires histological evidence.…”

“…A review of the original histology should be reconfirmed in such a situation. Radiation therapy has also been implicated as a risk factor for transformation into osteosarcoma [8,9,12,15]. There is no role for adjuvant radiotherapy or chemotherapy in osteoblastomas, possibly excepting recurrent or surgically unresectable cases [3,8,9].…”

“…Radiological, histopathological and other clinical analyses are poor variables for predicting outcomes. Tumor location and completeness of removal appear to be more important clinical factors than pathological features [12,13,14]. …”

“…Plain radiography usually shows a lytic lesion with surrounding mild sclerosis. The CT appearance of osteoblastoma is usually an expansile, well-demarcated, nonenhancing lytic or calcific intraosseous mass [12]. The lytic lesion could have a peripheral sclerotic rim.…”