UC Davis

Introduction

Epithelioid osteoblastomas are an extremely rare entity infrequently seen in the resection of benign bone tumors. First described in the early 20thcentury, it has only been reported a handful of times throughout literature. Although these tumors can present similarly to malignant bone lesions, it is important for an experienced pathologist to differentiate epithelioid osteoblastoma from osteosarcoma. We present the case and treatment of a young female who was discovered to have an epithelioid osteoblastoma of the femur.

Case report

We describe the case of a 19-year-old healthy female who presented with 3 weeks of progressive right-sided groin pain. After biopsy demonstrated, epithelioid osteoblastoma extensive curettage of the lesion followed by insertion of a short cephalomedullary intramedullary nail was performed. At 1-year follow-up,the patient was full weight-bearing without pain or recurrence.

Conclusion

Epithelioidosteoblastomas are a very rare entity in the diagnosis of benign bone tumors and are characterized as having aggressive features clinically, radiographically, and histologically. It is imperative that an experienced pathologist differentiates this lesion from osteosarcoma to guide treatment and to ensure the best possible outcomes.