J Korean Soc Magn Reson Med.  2011 Apr;15(1):72-76. 10.13104/jksmrm.2011.15.1.72.

Solitary Fibrous Tumor of the Ischiorectal Fossa : CT and MRI Findings

• Kim KH
• Cha SH
• Yeom SK
• Lee SH
• Chung HH

• KMID: 2041230
• DOI: http://doi.org/10.13104/jksmrm.2011.15.1.72

Abstract

Solitary fibrous tumor (SFT) is a rare neoplasm, which is usually presented as a pleural based mass, but can also occur in unusual locations based on its mesenchymal origin. However, the radiologic features of SFT occurred in the ischiorectal fossa have been rarely reported. In this case, we describe the MRI findings in a case of a SFT involving the ischiorectal fossa of a 36-year-old man. The tumor appeared as homogeneous iso-signal intensity relative to the adjacent muscle on T1 weighted images, a mixed high signal intensity on the T2 weighted images, and heterogeneous enhancement following the administration of the contrast material.

Keyword

Solitary fibrous tumor; Ischiorectal fossa; Magnetic resonance imaging (MRI); Computed tomography (CT)

MeSH Terms

Adult
Humans
Muscles
Solitary Fibrous Tumors

Figure

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  Fig. 1 Contrast enhanced coronal reformatted CT shows large, well defined mass with heterogeneous attenuation in the right ischiorectal fossa.

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  Fig. 2 Axial T1 weighted (a), T2 weighted (b), and contrast enhanced T1 weighted (c) images show soft tissue mass in right ischiorectal fossa. Mass exhibits homogeneous high signal intensity in (a) and heterogeneous high signal in (b), and heterogeneous enhancement in (c). The hyperintense area on T2-weighted images within mass revealed varying degree of enhancement.

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  Fig. 3 Sagittal contrasted enhanced T1 weighted images demonstrate multiple tubular structures arising from the subcutaneous fat of perineum. The low signal intensity of these structures, caused by a flow void effect, is suggestive of collateral feeding vessels (arrow).

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  Fig. 4 (a) The tumor is composed of short spindle cells with abundant stromal collagen bundles and ectactic vessels (hematoxylin and eosin staining, ×200). (b) The tumor cells are diffuse strong positive for CD34 staining (hematoxylin and eosin staining, ×200).

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