CT and MRI features of solitary fibrous tumor of kidney and literature review

Objective: To explore the imaging features and pathological manifestations of solitary fibroma tumor of kidney in order to improve the diagnostic accuracy of this disease. Methods: CT, MRI findings and clinico pathological features of one case with solitary fibroma tumor of kidney were retrospectively analyzed, and related literatures were reviewed. Results: The CT plain scan showed a solid soft tissue mass in the right renal parenchyma protruding into the renal pelvis, showing uniform high density. The CT value on plain scan was about 47 HU. On CT contrast enhanced scan, the enhancement of cortical phase was inhomogeneous, and the mass was further enhanced in parenchymal phase and secretory phase, and tended to be homogeneously enhanced. On the MRI plain scan, the mass showed isointense signal on T₁WI, obviously homogeneous and low signal on T₂WI, and slightly low signal on diffusion-weighted imaging (DWI). On multi-phase contrast enhancement, the mass showed progressive delayed enhancement and tended to be uniform. Microscopically, the tumor tissue was composed of intersecting bundles, the tumor cells were fusiform with no obvious heteromorphism, and mitosis was rare. Immunohistochemical results showed positive expression of CD34, CD99 and Vim. Conclusion: The solitary fibroma of kidney has characteristic imaging features, and should be considered in the differential diagnosis of renal solid tumors. (author)