A case of primary renal angiosarcoma

Abstract

A 78-year old man was diagnosed with a left bleeding renal cyst from CT scan results. Serial CT scans revealed the left kidney mass to be increasing in size and a new lesion in the liver. Renal cell carcinoma with liver metastasis was diagnosed and a radical nephrectomy performed. The initial pathological diagnosis was a benign chronic hematoma. However, the liver mass increased in size and multiplied, while another mass emerged in the twelfth thoracic vertebra with spinal paralysis and was immediately removed. Pathological findings for that specimen showed malignancy of stromal cell origin but low atypia. The renal specimen was re-evaluated using whole cross-section analysis and immunohistochemistry, and diagnosed as a primary renal angiosarcoma. Recombinant interleukin-2 therapy was started immediately; however, the patient died of metastatic disease 13 months after the initial operation. Although contrast imaging depicted the primary lesion as a non-specific hematoma with little focal pooling, and low-grade cytological atypia was shown pathologically, the angiosarcoma was extremely aggressive.

Figure 1

Abdominal CT scan findings obtained before the initial operation. An approximately 14 cm-sized mass with a distinct border was found located on the upper pole of the left kidney (A). The distribution of contrast material was limited to its margin without pooling. A new lesion that later developed in the sixth segment of the liver was shown as a low density area with poor enhancement (B).

Figure 2

Macroscopic appearance of affected kidney. The mass was located on the upper pole of the left kidney. The majority of the lesion was occupied by a non-specific hematoma and its periphery was composed of fibrous tissue. No neoplastic lesions were observed in macroscopic observations.

Figure 3

Microscopic findings of the primary renal lesion. Most areas of the specimens were occupied by the non-specific hematoma, whereas the tumor was located in the periphery of the hematoma (A). Spindle-shaped tumor cells with low-grade atypia had proliferated and invaded the adjacent parenchyma, which exhibited a sheet-like formation with no vascular architecture (B). The tumor cells were positive for CD31 (C), and VEGF (D).