Tehran University Medical Journal

Background and Aim: Osteoblastoma is one of the rarest primary bone tumors. Although, small bones of the hands and feet are the third most common location for this tumor, the hand involvement is very rare and few case observations were published in the English-language literature.                     

Materials and Methods: In this study, we report five cases of benign osteoblastoma of the hand, 3 in metacarpals and two in phalanxes. The clinical feature is not specific. The severe nocturnal, salicylate-responsive pain is not present in patients with osteoblastoma. The pain is dull, persistent and less localized. The clinical course is usually long and there is often symptoms for months before medical attention are sought. Swelling is a more persistent finding in osteoblastoma of the hand that we found in all of our patients. The radiologic findings are indistinctive, so preoperative diagnosis based on X-ray appearance is difficult. In all of our 5 cases, we fail to consider osteoblastoma as primary diagnosis. Pathologically, osteoblastoma consisting of a well-vascularized connective tissue stroma in which there is active production of osteoid and primitive woven bone. Treatment depends on the stage and localization of the tumor. Curettage and bone grafting is sufficient in stage 1 or stage 2, but in stage 3 wide resection is necessary for prevention of recurrence. Osteosarcoma is the most important differential diagnosis that may lead to inappropriate operation.

Background: Osteoblastoma is one of the rarest primary benign bone tumors which accounts for 1% of all bone neoplasms and 3.5% of benign bone tumors, with the potential for local invasion and recurrence. Osteoblastoma is not homogeneous. Differences in histological details have led to the division of these lesions into subtypes. The histologic features in most cases are distinctive, there are various changes that make the diagnosis challenging. Although involvement of this disease is more in the spines or small long bones, but it has been reported involvement of jaws in this disease. Correct diagnosis is very important because it may be misdiagnosed osteosarcoma  with hypercellular cases.

Case presentation: In this case report, it is described patient a 7-year-old girl with a lesion in the posterior maxilla and bone resorption in May 2016, Sari, Mazandaran province, Iran. Differential diagnosis of the radiological and clinical findings suggested an osteosarcoma. In terms of pathology, osteoblastoma was included a well-vascularized connective stroma tissue with plenty of veins which osteoid and primitive woven bone can be seen actively. In microscopy diagnosis, samples were shown cortical bone with a natural appearance, prominent osteoblasts and surrounding granulation tissue containing blood vessels that confirmed maxilla osteoblastoma. The lesion was examined by histopathology method for final recognition and the results revealed osteoblastoma.