Solitary fibrous tumor (SFT) is an infrequent but distinct neoplasm, which generally arises from submesothelial connective tissue in the pleura. SFT is rarely recognized in extrathoracic sites, and histologically identical conditions have also been reported in the retroperitoneum, although their pathophysiology has not been extensively investigated.
We present four cases of primary SFT in the retroperitoneum, and review 37 similar cases in the previous literature.
About 40% of patients were asymptomatic, and 19.2% and 15.4% presented with an abdominal mass and urinary symptoms, respectively. The tumor size ranged between 2 and 26 (mean 9.1) cm. Sixty-three percent of tumors showed nonspecific development with haphazard distribution of bland short spindle or polygonal cells with or without collagenous bundles and stromal hyalinization. In 22.0%, hemangiopericytomatous appearance was seen. About 15% of cases showed histologically malignant characteristics. The tumor cells were immunoreactive for vimentin in all cases, CD34 in 91% and Bcl-2 in 86%. All tumors were excised, and in 85.4% of cases, tumors did not recur postoperatively for 6 to 48 months. No significant difference was found between the recurrence rate of histologically benign and malignant cases. Cases positive for both CD34 and Bcl-2 had no recurrence.
The identification of SFT in the retroperitoneum is of importance because histopathological indicators of malignancy are not necessarily associated with clinical malignant potential in many cases of retroperitoneal SFT. Retroperitoneal SFT showing typical pathological features with expression of CD34 and Bcl-2 is associated with a favorable outcome following excision.
"Glomus tumors exhibit a perivascular pattern of growth with cuboidal epithelioid cells, have an organoid pattern of the glomus organ and lack the characteristic perivascular concentric growth of myopericytoma (1,7–9). A solitary fibrous tumor is different from myopericytoma, as it exhibits immunoreactivity for the expression of vimentin, CD34, Bcl-2 and CD99 (1,10). In the present case, the absence of expression of CD34, CD99 and vimentin provided evidence for the differential diagnosis of renal myopericytoma. "
[Show abstract][Hide abstract] ABSTRACT: Myopericytoma is a rare neoplasm that generally arises from the skin and superficial soft tissues of distal extremities, and is particularly rare in the visceral organs. The current report presents a case of giant myopericytoma showing kidney involvement, which is extremely rare. A 39-year-old male presented to the Department of Urology with a 2-month history of a painless and palpable mass in the region of the left abdomen. Unenhanced computed tomography revealed a 9×10×18-cm(3) mass that was heterogeneous with central lower density. The patient underwent radical nephrectomy, including lymphadenectomy, without adjuvant therapy. The tumor was composed of spindle-shaped myoid cells with a concentric arrangement and showed immunoreactivity for smooth muscle actin and cluster of differentiation (CD)10, and had a Ki-67 index of <1%; however, staining was negative for CD34, desmin, S-100 protein, cytokeratin, human melanoma black (HMB)-45, B-cell lymphoma (Bcl)-2 and CD99. Routine follow-up revealed no local or distant metastatic signs of reccurrence for 20 months. The present report shows that renal myopericytoma may be a benign tumor, and surgical excision without adjuvant therapy may be the only potentially curative treatment approach.
[Show abstract][Hide abstract] ABSTRACT: Background
Solitary fibrous tumor (SFT) is rare soft tissue tumor, and it occurs most commonly in the pleura. Retroperitoneal SFT is generally found by palpable mass or abdominal distention. Here we report a case of SFT presenting pollakiuria.
A 64-year-old man was referred to our hospital for pollakiuria. Contrasted-enhanced computed tomography revealed a heterogeneously enhanced pelvic tumor of approximately 10 × 8 × 7 cm. Invasion of the surrounding organs, distal metastasis, and lymph node swelling were absent. Therefore, surgical resection was performed. The resected specimen was a 13 × 8 × 5.5-cm encapsulated elastic hard tumor weighing 420 g. Histologically, the tumor consisted of oval or spindle cells growing in a random manner in a collagenous matrix. Immunohistochemically, the specimen was positive for CD34, bcl-2, as well as vimentin and negative for c-kit. On the basis of these findings, a retroperitoneal solitary fibrous tumor (SFT) of the pelvis was diagnosed.
Surgery is the primary treatment for SFT, and pathologically negative margins are important for good prognosis.
BMC Research Notes 10/2012; 5(1):593. DOI:10.1186/1756-0500-5-593
"Almost all SFTs have been reported in the pleura, but they have also been rarely reported in other sites, including the liver, kidney, retroperitoneum, and soft tissues . Goodlad and Fletcher  reported that 6% of all SFTs originated from the pelvis. "
[Show abstract][Hide abstract] ABSTRACT: An 83-year-old man underwent complete resection of a large malignant solitary fibrous tumor in the retroperitoneum in 2006 and of a local recurrent tumor in 2010. In 2011, he was admitted to our hospital because of hypoglycemia. His serum glucose level was very low, and his levels of insulin and C-peptide were low. Furthermore, he had a recurrent tumor in the retroperitoneum and pelvis. Immediately after the third surgery for complete resection, he had no hypoglycemic episodes and his serum glucose level was within the normal range. Immunoblotting analysis revealed a high-molecular-weight form of insulin-like growth factor II in the patient's serum and in the protein extract obtained from the resected specimen in 2011. To our knowledge, this is the first report of non-islet cell tumor hypoglycemia caused by a malignant solitary fibrous tumor secreting a high-molecular-weight form of insulin-like growth factor II at the second recurrence.
Case Reports in Oncology 05/2012; 5(2):420-7. DOI:10.1159/000340012
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