Primary Epithelioid Angiosarcoma of the Tibia: A Case Report and Review of the Literature.

Angiosarcoma of the bone is very rare, accounting for less than 1% of all malignant bone tumors. We report our experience with an epithelioid hemangiosarcoma arising in the proximal tibia and a review of the literature. The patient, an 85-year-old male, was referred to our institution because of left knee pain that had persisted for five months, and bone radiolucency was observed in the proximal tibia. A bone and prostate biopsy was performed due to a suspicion of prostate cancer and bone metastasis. The positron emission tomography-computed tomography (PET-CT) showed accumulation in the prostate and proximal tibia, and the prostate-specific antigen (PSA) level was high at 14.11 ng/mL. Therefore, we diagnosed the patient with bone metastasis of prostate cancer and performed curettage and cement filling. However, postoperative pathological diagnosis revealed an epithelioid hemangiosarcoma, and we considered amputation. Two months after curettage, the patient underwent transfemoral amputation because of local recurrence. Eight months after amputation, he died due to multiple metastases. Approximately 20% of cases with epithelioid hemangiosarcoma have multiple metastases at the time of initial diagnosis, and it is sometimes difficult to distinguish from bone metastases of cancer because they may be arranged in foci or on cords. There are few reports of effective adjuvant therapy, and the clinical course can be rapid, so early amputation should be considered.