SOLITARY FIBROUS TUMOR MRI
A 57-year-old man presented with a five-year history
of increasing general abdominal pain, weight loss, and difficulty voiding.
Imaging FindingsComputed Tomography
Magnetic Resonance Images, Sagittal View
Magnetic Resonance Images, Coronal View
Gross Pathology Specimen
Pre-biopsy, non-contrast axial CT through the upper pelvis demonstrates a large soft tissue mass displacing the bowel loops.
There is one focal area of lower attenuation, perhaps representing fat.
Pre- and post-contrast sagittal MR images of the pelvis show that the lesion is homogeneously slightly hyperintense to muscle.
Pre- and post-contrast coronal images demonstrate hyperintensity on T1. This is likely a bladder or prostate lesion.
The differential diagnosis of a large bladder mass includes transitional cell carcinoma (although this is an unusually large presentation), adenocarcinoma, squamous cell carcinoma, and schistosomiasis.
The differential diagnosis for a large prostate mass includes adenocarcinoma and sarcoma.
DiagnosisSolitary fibrous tumor
The specimen consists of a large (13 cm), well circumscribed, firm mass attached to the posterior serosal bladder wall. The mass does not invade the bladder. The gross appearance suggests a benign lesion. The low-power view of the cells shows a variegated appearance caused by the mixture of hypercellular and hypocellular areas. The cells are bland and spindle with associated characteristic collagen fibers. The sample was strongly positive for CD-34, which supports the diagnosis of solitary fibrous tumor.
The differential diagnosis for bladder filling defects includes:
- Malignant tumors (Primary bladder tumor, metastasis [e.g., prostate, uterus, cervix, colon])
- Benign bladder neoplasms (leiomyoma, fibroepithelial polyp, hemangioma, adenoma, pheochromocytoma)
- Blood clot
- Edema (adjacent to calculi)
- Enlarged prostate gland
- Muscular wall hypertrophy
- Post-operative change
- Fungus ball
Solitary fibrous tumors are likely of either mesothelial cell origin or fibroblast/primitive mesenchymal cell origin. The most common locations for these tumors are the pleura and mediastinum. Other reported locations include the abdominal cavity, parotid gland, pericardium, ovary, liver, intestine, lung, orbit, upper respiratory tract, bladder and periosteum. The unifying characteristic of solitary fibrous tumors is positive staining for CD-34, resulting from the spindle cells. Cases have been reported in patients from 9 to 86 years of age (average age: 57 years) and appear to be nearly evenly distributed between males and females.
CT is useful for assessment of pelvic sidewall, adjacent viscera, and evaluation of lymphadenopathy; it is limited in differentiating post-operative or post-radiation change vs. tumor. CT staging is 75% accurate.
MR is better than CT for staging and for evaluation of bladder base or dome tumors. T2 sequencing is effective for evaluating the urine-bladder wall interface, while T1 shows the interface between the bladder and perivesical fat. Gadolinium helps assess small tumors.
ReferencesZagoria RJ, Tung GA. Genitourinary Radiology: The Requisites. Mosby, St. Louis, 1997.
Zotalis G, Hicks DG. Solitary fibrous tumor of the soft tissues. Archives of Hellenic Pathology. 11(3), 1997.
Dear Visitors: Nothing on this World Wide Web site should be considered medical advice. Only your own doctor can help you make decisions about your medical care. It is not the policy of the Brigham and Women's Hospital Department of Radiology to provide consultation on the World Wide Web or via e-mail. If you have a specific medical question or are seeking medical care, please call the Brigham and Women's Hospital toll-free physician referral line at 1-800-294-9999.
Is this a mirrored page?
The official homepage of the BrighamRAD Teaching Case Database is http://brighamrad.harvard.edu/education/online/tcd/tcd.html
Contact the BrighamRAD Design Team for additional