Aggressive osteoblastoma of the temporal bone: a case report and review of the literature

Aggressive Osteoblastoma Involving the Navicular Bone of Foot: A Rare Tumor in a Unique Location

Aggressive osteoblastoma (AO) is a rare variant of osteoblastoma characterized histologically by epithelioid osteoblasts and clinically by local recurrences if not excised completely. Aggressive osteoblastoma has been described in various unusual sites; however, based on our search of the literature, involvement of the tarsal navicular has not been previously described. Herein, we report what we believe to be the first case of aggressive osteoblastoma involving the tarsal navicular in a 35-year-old woman. The tumor showed osteoid surrounded by epithelioid cells along with numerous osteoclastic giant cells. Absence of necrosis, mitosis, and infiltration into the surrounding native bone helped rule out the possibility of low-grade osteosarcoma.

Pediatric cranial osteoblastoma: Technical note of surgical treatment and review of the literature

Osteoblastoma of the skull is a rare entity, and they account only for 2-4% of all the cases of osteoblastoma. We perform a comprehensive review of the pertinent literature on the subject and we report a case of a 3-year-old girl presenting with a 6-month history of a supraorbital mass and exophthalmos due to an osteoblastoma of the frontal and ethmoid bones involving the orbit and anterior skull base. A 3D printed model of the patient's skull was used for the preoperative planning and reconstruction strategy. Total en-bloc resection of the tumor followed by immediate reconstruction was achieved. No recurrence was detected 3 years after the surgery. Gross total resection is strongly advised with skull osteoblastoma, especially in young age, because of the risk of the recurrence and malignant transformation. 3D printing is proven to be a valuable tool to enhance surgical performance by avoiding complications while achieving total resection with accurate reconstruction. Long-term follow-up is important to detect recurrences and improve the management of these young patients.

Aggressive Cranial Osteoblastoma of the Parietotemporo-Occipital Bone: A Case Report and Review of Literature with Special Emphasis on Recurrence/Residue

Osteoblastoma is a rare nonfibroblastic osteoid tissue-forming primary bony tumor usually arising in the medullary cavity/diploic space of any bone. The calvarium is an extremely rare site of its origin. Clinically, 2 types of osteoblastoma are noted: benign/conventional/typical and aggressive/high grade. Their imaging features are nondifferentiating and nonspecific, histopathologic features have a few subtle but nonspecific differences, and they have highly distinct clinical behavior. We report an extremely rare case of a patient with large aggressive cranial osteoblastoma, who developed massive inoperable multifocal recurrence 15 months after total en bloc resection with wide margins. A concise review of cases of aggressive osteoblastomas involving the cranium available in the English literature is also presented as an update.

Rare Aggressive Calvarial Osteoblastoma with Dural Invasion

We report a rare case of an aggressive osteoblastoma (OB) involving the calvaria and infiltrating the dura, a finding that was not previously reported in the literature. A 50-year-old man presented with a progressive mass in the left frontoparietal skull with headaches and a six-month history of sudden mass growth. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large skull lesion with areas of hemorrhage, calcification, restricted diffusion, and enhancement.  A left temporoparietal craniotomy with a complete resection of the tumor with grossly clean margins was performed. Follow-up at 60 months showed a stable clinical picture and no sign of local recurrence of the lesion on MRI.

Osteoblastoma Mimicking an Idiopathic Intracranial Hypertension Syndrome

Osteoblastomas are rare, benign bone tumors mainly arising from the long bones and the posterior vertebral arches. Skull localizations account for approximately 15% of cases. A total amount of thirty cases involving the temporal bone are reported in the literature. Clinical presentation of temporal osteoblastomas often includes local pain and swelling, while 7^th and 8^th cranial nerve impairment is rare. We report the novel finding of increase intracranial pressure syndrome secondary to dominant transverse-sigmoid sinus junction compression caused by a small temporal bone osteoblastoma. Excision of the tumor with the restoration of venous flow in the sigmoid sinus was followed by a prompt clinical improvement. In the management of patients with a venous sinus compression, restoration of venous drainage should be a priority.

Malignant Transformation of a High-Grade Osteoblastoma of the Petrous Apex with Subcutaneous Metastasis

We describe the clinical presentation, management, and pathologic findings in a case of osteosarcoma of the petrous apex with an atypical metastasis to the lower abdominal wall. We retrospectively reviewed the record of a 49-year-old man who was diagnosed with a right petrous apex lesion, which biopsy identified as a high-grade osteoblastoma. After two attempts at en bloc resection were not curative, radiation and chemotherapy were recommended. The patient subsequently developed a cutaneous lower abdominal mass that was diagnosed as an osteosarcoma. Meanwhile, the petrous apex tumor continued to grow despite treatment until the patient died from the burden of disease. Temporal bone osteoblastomas and osteosarcomas are both extremely rare, and they can be difficult to differentiate histologically. Our case illustrates this difficulty and demonstrates the possibility of a high-grade osteoblastoma's malignant conversion to an osteosarcoma.