Osteoblastoma of the Second Metatarsal: A Case Report

Aims: To present the clinical, radiographic and histopathological features of an osteoblastoma localized to the second metatarsal of a 50-year-old woman that was successfully treated with intralesional curettage.
Case Presentation: A 50-year-old woman presented with localized swelling and tenderness of the right forefoot of 3 years’ duration. She reported increased swelling and intense pain, worse at night, during the last 6 months. Imaging included plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) and was indicative of a benign process. An expansile osteoblastic lesion was identified in the diaphysis of the second metatarsal on x-rays. A lytic bone lesion surrounded by an intact cortical rim with evidence of intralesional ossifications was evident on both CT scan and MRI. In the latter, there were also signs of bone marrow and soft tissue edema. The lesion was treated surgically with curettage and an osteoblastoma was diagnosed at biopsy. No further treatment was undertaken. No recurrence has occurred during a 7-year follow-up.
Discussion: Osteoblastoma is a rare benign osteoblastic neoplasm with a scarce localization to the metatarsals. Diagnosis is not difficult when the typical clinical and imaging features are present. Surgical treatment may offer intralesional curettage or wide resection to reduce recurrence rates in locally aggressive tumors, recurrent lesions, or in cases with suspected malignancy. In the reported case the lesion was misdiagnosed as an area of osteomyelitis. Definitive diagnosis was based on curettage-excision of the lesion indicating the typical histological pattern of osteoblastoma.
Conclusion: The clinical and radiographic appearance of osteoblastoma may be variable and can mimic other tumors or tumorous conditions. Differential diagnosis may be especially challenging and histological analysis of the biopsy specimens may be the diagnostic cornerstone.