Intraosseous Leiomyoma of the Tibia. A Case Report.

Introduction: Leiomyoma is benign smooth-muscle tumor most commonly arising in the uterus, the gastrointestinal tract, and the skin. Leiomyomata are infrequently seen in the extremities and rarely seen in the bone. It is usually presented by a gradually increasing pain with nonspecific radiological findings, and could be a differential diagnosis for wide range of bone tumors.

Case Presentation: We report a case of a 73-year-old Japanese female patient with a painful intraosseous leiomyoma involving the proximal tibia. The patient had undergone tumor excision with wide margin, immediate weight bearing was allowed, pain had been relieved and the patient was satisfied with no recurrence, malignant change, distant metastases or functional impairment. We reviewed all published cases of intraosseous leiomyomata in English literature.

Conclusion: Diagnosis of Intraosseous leiomyoma of the extremities is difficult due to extreme rarity of the tumor and absence of pathognomonic radiological sign in X-ray, CAT, or even MRI. While the exact diagnosis is only achieved by histopathological examination and with immunohistochemistry stains, which can differentiate it from malignancy, especially from the much less rare leiomyosarcoma. Orthopedic oncologists have to include this rare benign tumor in the differential diagnosis of any intraosseous lesion with gradually worsening and long-standing pain, despite of benign imaging characters. Different histological patterns of leiomyoma do exist, however there is no difference in prognosis or treatment options. Treatment standard includes wide excision with autologous bone graft whenever possible. Internal fixation may be necessary if the bone defect is large or there is thinning out of the cortex that may lead to pathological fracture.