Intrarenal solitary fibrous tumor of the kidney report of a case with emphasis on the differential diagnosis in the wide spectrum of monomorphous spindle cell tumors of the kidney

Solitary fibrous tumor of the renal pelvis: A case report

BACKGROUND

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm. SFT derived from the renal pelvis is an exceedingly rare entity. In this study, we report a case of renal pelvis SFT and review the relevant literature on this rare tumor.

CASE SUMMARY

A 76-year-old man was hospitalized due to right lumbar and abdominal pain. Abdominal computed tomography showed a hypervascular space-occupying renal lesion, sized 2.3 cm × 1.8 cm. Based on the computed tomography findings, the patient was diagnosed with right renal pelvis tumor and underwent nephrectomy. Postoperative immunohistochemical results confirmed the diagnosis. As of the 3-year follow-up, there were no signs of recurrence, and the patient has recovered well.

CONCLUSION

We report a rare case of SFT derived from the renal pelvis and discuss the imaging and histopathological features that distinguish renal pelvis SFT from other renal pelvis tumors.

Solitary fibrous tumor of the orbital region: report of a case with emphasis on the diagnostic utility of STAT-6

Solitary fibrous tumor (SFT) is a relatively rare soft tissue neoplasm originally described in the pleura. Since its first description, several cases arising in extra-pleural superficial and deep soft tissues have been reported in the literature. SFT arising in the head and neck region is quite rare, representing about the 6% of all SFTs, and the sinonasal tract is the most common involved region, followed by the orbit, the oral cavity and the salivary glands. Herein, we report the clinico-pathologic features of a rare case of SFT of the orbital region, emphasizing the diagnostic role of the immunomarker STAT-6. A 52-year-old female presented to our hospital with a nodular mass in the left orbital region. Histological examination revealed a uniformly hypercellular tumor composed of pale to slightly eosinophilic bland-looking spindle cells arranged in intersecting short fascicles with interspersed stellate-shaped, keloid-type collagen fibers. Notable hypocellular areas, perivascular hyalinization and hemangiopericytoma-like branching vascular pattern were absent. Immunohistochemically, neoplastic cells were diffusely positive for vimentin, CD34 and STAT-6. The introduction of STAT-6 in daily diagnostic practice is helpful to confidentially render a diagnosis of SFT even in the presence of unusual morphology and site.

Solitary fibrous tumor with atypical features of the paravesical space: benign clinical course at the 10-years follow-up. Report of a case and review of the literature

Extra-pleural solitary fibrous tumor (SFT) is a relatively rare soft tissue neoplasm, with only rare cases reported in the pelvic cavity. Most SFTs are histologically benign, with only a few malignant cases reported in the literature so far. We report a rare case of SFT arising in the paravesical space of a 79-year-old man. Histologically the tumor corresponds to an “intermediate risk tumor” according to a risk stratification scheme for metastatic potential, which incorporates patient age, tumor size, mitotic activity and necrosis. Notably tumor showed a benign clinical course without evidence of local recurrence after a 10-years follow-up. Tumor was composed of both spindle and epithelioid cells variably set in a fibro-myxoid stroma, with focal pleomorphic, necrotic and highly mitotic (> 4 mitoses/10HPF) areas. Immunohistochemistry, showing a diffuse CD34 and STAT6 immunoreactivity, supported the diagnosis of SFT. The present case emphasizes that the clinical course of the pelvic SFTs with atypical morphological features is unpredictable on the basis of morphology alone, and thus the term “SFT with atypical features, including the risk stratification class” should be preferred to “malignant SFT”.

Solitary fibrous tumor of the spermatic cord: A case report and literature review

A 31-year-old male patient with a six-year history of left inguinoscrotal swelling was admitted to the Second Xiangya Hospital (Changsha, China). The mass was not found to be associated with intraperitoneal pressure. Ultrasonography and computed tomography examinations demonstrated several solid, botryoidal masses involving the spermatic cord, with limited capacity of mobility. The demarcation between the masses and the left testicle was clear; thus, the masses were removed by a left spermatic cord tumor resection via a left inguinal approach, under epidural anesthesia. Positive staining of the tumor markers, CD34⁺, CD99⁺ and Bcl-2⁺, was confirmed by pathological examination following surgery, and a solitary fibrous tumor of the spermatic cord was diagnosed. No recurrence and metastasis were observed in the patient during the subsequent 25-month follow-up period.

Renal malignant solitary fibrous tumor with single lymph node involvement: report of unusual metastasis and review of the literature

Solitary fibrous tumors are rare mesenchymal spindle cell neoplasms that are usually found in the pleura. The kidneys are an uncommon site and only few cases of renal solitary fibrous tumor exhibit malignant behavior metastasizing to the liver, lung, and bone through the hematogenous pathway.

The value of immunohistochemistry in diagnosing primary renal synovial sarcoma: a case report and literature review

Primary synovial sarcoma of the kidney is rare and difficult to diagnose with 100% accuracy without the use of up-to-date histopathologic methods. Immunohistochemical procedures are well established and are continuously expanding and improving. Currently, these methods are successful in up to 90% of tumor identification. The remaining cases will ultimately benefit by combining immunohistochemistry with tumor-specific genetic marker identifiers, the latter of which are increasing in availability for tumor diagnosis. The principal immunohistochemical methods enlisted in establishing a diagnosis of primary renal synovial sarcoma are summarized.

A huge malignant solitary fibrous tumor of kidney: case report and review of the literature

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1603694556107408.

Solitary fibrous tumor (SFT) is a spindle cell neoplasm that rarely occurs in the kidney. Malignant SFT of the kidney is particularly rare. Here, we report a 66-year old woman with a right flank mass that has been proved clinically and radiographically. Grossly, the largest diameter of the mass were measured up to 23 cm, was poorly circumscribed. Approximately 80% of the neoplasm consisted of hyperchromatic and pleomorphic spindled cells surrounding staghornlike blood vessels. Tumor cells frequently had mitoses and necrosis. However, the remainder of the mass was composed of haphazard, storiform or short fascicular arrangements of spindle cells in a loose myxoid to fibrous stroma. Immunohistochemically, we observed diffusely strong CD34 staining and an 85% Ki-67 proliferative index. The tumor partly showed negative CD34 and a 20% proliferative index. To our knowledge, this is the largest malignant renal SFT in the reported literatures and shows an obviously high proliferative index.

Two malignant solitary fibrous tumors in one kidney: Case report and review of the literature

Malignant solitary fibrous tumors of the kidney are very rare. Two tumors in one kidney is particularly rare and has not been previously reported. Due to the non-specific clinical symptoms, it is difficult but also very significant to give a definite diagnosis. Here, we report a case of two renal masses in one kidney. A 56-year-old man was admitted to our hospital complaining of shortness of breath, weakness, hyperhidrosis and intermittent hypoglycemia of 1-year duration without gross hematuria or lumbago. Imaging studies revealed two masses manifesting as inhomogeneous, with soft-tissue density and having no clear boundaries with the kidney. The patient was initially diagnosed with space-occupying lesions of the left kidney (with suspicions of renal cell carcinoma) and left radical nephrectomy was performed. Histologically, the tumors consisted of ovoid or spindle cells, and a hemangiopericytoma-like pattern and cellular atypia was observed in certain areas. Mitotic figures were more than 4 per 10 high-power fields. Immunohistochemically the tumor cells were positive for CD34, CD99 and vimentin. Accordingly, a diagnosis of malignant solitary fibrous tumor of the left kidney (low-grade malignance) was established. Postoperative follow-up of 10 months did not find tumor recurrence or metastasis and hypoglycemia was resolved with the removal of the tumors.

Solitary fibrous tumor in the thigh: review of the literature

Solitary fibrous tumors (SFT) of extremities, especially the thighs are very rare. Despite SFTs are generally benign, well-circumscribed soft tissue tumors new cases should be presented and followed up carefully to monitor their biological behavior. In general for tumor classification a biopsy is state of the art. Histological including immunohistochemical patterns for SFTs are defined. MRI and ultrasound are not sufficient for differential diagnosis. Once property identified and defined by size and location, resection with intact tumor capsule may result in full recovery of the patient. Reviewing the literature there are no validated reasons for a wider resection. The current patient was a 41-year-old male. Four years after an arthroscopy of the left knee the patient has been suffering an ongoing swelling of the lateral thigh. Because MRI scan data suggested a synovial sarcoma a biopsy was performed. The tumor was classified as a benign SFT. The diagnosis based on histological findings and the presence of the positive immunohistochemical markers Vimentin, CD34, and CD99. The complete tumor resection with intact capsule was achieved in a final operation. Clinical and in MRI after 54-month outcome period there were no local recurrences.