PMC3573797_01
CT findings. A large right renal tumor was observed on plain CT (left). Blood vessels were enhanced in the early phase (middle), and the tumor was enhanced in the delayed phase (right).
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F1
A physical examination revealed a hard right abdominal mass, and a subsequent CT scan detected a large right renal tumor, which was suspected to be a renal cell carcinoma (fig. 1).
Microscopic features of the solitary fibrous tumor. The primary renal tumor displayed a hemangiopericytomatous growth pattern (upper left). Immunohistochemical staining of CD34 was positive in 55% of the primary tumor (upper right). Resected tissue from the liver (middle left) and lungs (lower left). CD34 expression was completely absent from the resected liver tumor (middle right) but weakly positive in the resected lung tumor (lower right).
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F2
Immunohistochemical staining was positive for CD34, vimentin, and CD99 and negative for keratin, EMA, CD10, CD31, factor VIII, alphaSMA, Bcl-2, S-100, and CD117 (fig. 2). Although immunohistochemical staining for CD34 was negative in the resected tissue from the liver and weakly positive in the resected tissue from the lungs, the specimens were positively stained for vimentin and CD99 and negative for CD10, factor VIII, alphaSMA, Bcl-2, and S-100 (fig. 2).
Follow-up computed tomography revealed liver metastasis and lung metastasis.
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F3
However, 8 years after the original operation, follow-up CT detected a lung nodule and multiple liver nodules (fig. 3), which were consistent with metastasis from the primary renal SFT.