Solitary fibrous tumour of the kidney with sarcomatous overgrowth

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified. Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.

Cell and extracellular matrix growth theory and its implications for tumorigenesis

Cells associated with an abnormal (cancerous) growth exchange flows, morph freely and grow hand-in-glove with their immediate environment, the extracellular matrix (ECM). The cell structure experiences two mass flows in counterflow. Flowing into the structure are nutrients and flowing out is refuse from the metabolically active biomass within. The physical effect of the evolution of the cell and extracellular structure is more flow and mixing in that space, that is, more mixing than in the absence of a biological growth in that space. The objective of the present theory is to predict the increase in the size of the cell cluster as a function of its structure, and also to predict the critical cluster sizes that mark the transitions from one distinct cluster configuration to the next. This amounts to predicting the timing and the main features of the transitions from single cell to clusters with two, four, eight and more cells, including larger clusters with cells organized on its outer surface. The predicted evolution of the size and configuration of the cell cluster is validated successfully by comparison with measurements from several independent studies of cancerous and non-cancerous growth patterns.

Angioleiomyoma of the lumbo-sacral region with unusual keloid-like collagen fibers

Angioleiomyoma is a benign soft tissue tumor which usually occurs in superficial or deep soft tissues. Only rarely does this tumor occur at unusual sites, including retroperitoneum. We present a rare case of lumbo-sacral angioleiomyoma in a 54-year-old man. Apart from this unusual site, the most striking morphological feature was the presence of numerous keloid-like collagen fibers interspersed among the fascicles of the neoplastic cells. Radiological, morphological and immunohistochemical features are presented, and differential diagnosis with its potential morphological mimickers is discussed.

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 involving urinary bladder: a case report and literature review

Solitary fibrous tumor (SFT) is a rare fibroblast stroma tumor involving the mediastinum and pleura. We herein describe an SFT of bladder which is extremely rare and review 29 similar cases in the last decades. We present a case of a 52-year-old male patient who suffered from urinary urgency and frequency for 12 months. Non-contrast computed tomography (CT) showed a slightly high density calcified mass with 70 mm × 61 mm in diameter. Contrast-enhanced CT demonstrated the mass was slightly enhanced. Cystoscopy revealed a huge mass with flat surface. Histopathological review of the biopsy specimens could not confirm the diagnosis. Partial cystectomy was then performed and the diagnosis of SFT was confirmed by immunohistochemistry. The patient is doing well at 12 months follow-up without recurrence and metastasis. In conclusion, the diagnosis of SFT involving bladder should combine clinical presentation and imaging features. Complete surgical resection is the primary method and long-term follow-up is necessary.

Localized giant solitary fibrous tumor of the scrotum: a rare case report and literature review

Background

A solitary fibrous tumor (SFT) is a fibroblastic mesenchymal tumor initially thought to originate from the pleura but that may arise at almost any anatomic site. It is mostly benign, and surgical resection is usually the best treatment option. An SFT involving the scrotum is extremely rare. Case presentation: We herein report an uncommon case of a 22-year-old man who presented with a huge asymptomatic scrotal mass that had begun growing 3 years before presentation. Contrast-enhanced computed tomography revealed a heterogeneous, well-circumscribed scrotal mass with soft tissue density. No invasion of the surrounding organs, distal metastasis, or lymph node swelling was present. Complete resection of the mass was successfully performed. The specimen was a 14.5 × 12.0 × 9.5 cm encapsulated tumor that weighed 970 g. After pathological analysis, we confirmed the diagnosis of SFT. This diagnosis was based on clinical findings, histological morphology, and immunohistochemistry. No recurrence or metastasis was observed during a 3-year follow-up.

Conclusion

SFTs have an unpredictable clinical course, and they are difficult to diagnose and easy to misdiagnose. A scrotal location is extremely rare. Complete resection of the mass is the treatment of choice and is associated with a high success rate and low recurrence rate.

Malignant Solitary Fibrous Tumour of the Breast Mimicking a Benign Tumor

Solitary fibrous tumour (SFT) of the breast is exceedingly uncommon. Radiological assessment usually shows benign features. We report on a case of malignant SFT of the breast, while emphasizing the need for additional immunostains to reach a definitive diagnosis. Standard treatment consists of lesion removal with adequate margins.

Dedifferentiated Solitary Fibrous Tumor: A Concise Review

Solitary fibrous tumor (SFT) is a unique mesenchymal neoplasm that was originally believed to be of submesothelial origin. Eventually, SFT expanded to include what was previously called hemangiopericytoma in other regions of the body that had similar immunohistochemical and morphologic features. Although most are benign, many studies have tried to identify histologic features that predict which tumors will behave in an aggressive manner. Recently, dedifferentiation has been described in rare cases of SFT and does appear to correlate with a more aggressive clinical course. Dedifferentiated SFT occurs in a similar age range and location as conventional SFT and can resemble multiple different malignant entities. Utilization of ancillary studies and thorough tissue sampling is important to reach the correct diagnosis. The morphologic features, immunohistochemistry, molecular alterations, and prognosis will be discussed.

Giant solitary fibrous tumor of the pleura with high-grade sarcomatous overgrowth accompanied by lipid-rich, rhabdomyosarcomatous, and pleomorphic components: A case report

RATIONALE

Solitary fibrous tumors are mesenchymal tumors presenting as fibroblastic neoplasms with prominent branching vascular patterns, which are often generated from the pleura. Most solitary fibrous tumors are benign; however, some can turn malignant. High-grade sarcomas from solitary fibrous tumors include multidirectional histopathological components.

PATIENT CONCERNS

We describe our experience of a giant high-grade sarcoma with mixed components generated from a solitary fibrous tumor of the pleura in a 67-year-old female patient presenting with cough and left-sided chest pain. The patient had been diagnosed with a pleural mass in the left chest by X-ray about 30 years earlier. However, the tumor was allowed to grow, without surgical intervention, for a long time.

INTERVENTIONS

Thoracic surgeons performed the removal of the giant pleural tumor; the tumor measured 18.0 × 14.5 × 10 cm in size, and was considered a giant tumor generated from the pleura of the left chest cavity.

DIAGNOSES

The surgically removed tumor was solid and light brownish, and included myxoid and arabesque pattern lesions. The tumor also showed hemorrhagic and necrotic lesions. Moreover, spindle cells with less atypia, resembling fibroblasts, were noted. These spindle tumor cells were CD34- and Stat6-positive, suggesting a solitary fibrous tumor. Some of the spindle tumor cells were surrounded by thick collagenous fibers. Considering that the tumor originated from the parietal pleura, the tumor was defined as a solitary fibrous tumor in origin. The tumor also comprised high-grade sarcomatous components; these included lipid-rich, rhabdomyosarcomatous, and pleomorphic components. The high-grade sarcoma component included bizarre tumor cells with severe atypia.

OUTCOMES

Tumor recurrence occurred in the left chest about 4 months after the surgery, and the patient died 8 months postoperatively.

LESSONS

The present case clearly demonstrates that a solitary fibrous tumor can develop into high-grade sarcomatous overgrowth, including lipid-rich, rhabdomyosarcoma, and pleomorphic sarcoma components, if left untreated for a prolonged period. This case provides profound insights about the natural history, histogenesis, differentiation, and malignant transformation of solitary fibrous tumors.

Solitary fibrous tumour presenting with a single bone metastasis: report of six cases and literature review

Background

Solitary fibrous tumour (SFT) is a rare soft tissue sarcoma with a low metastatic potential. A higher metastatic rate is observed in the high-grade/dedifferentiated variant. The most common expected site of distant spread are the lungs and the liver. Bone involvement is generally viewed as a late stage of disease spread. We report on a retrospective series of SFT patients relapsing with a single distant bone recurrence as first metastatic event, without evidence of other organ involvement.

Case presentation

All patients affected by a single distant bone metastasis from SFT as first distant event, without any evidence of other site of metastasis, observed at our Institution, were considered. Bone involvement from SFT was pathologically assessed in all cases and confirmed by expert pathologists. A total of six patients were retrospectively identified. Primary tumour arose from the meninges in four patients, from soft tissues in two. Bone metastases were located to the vertebrae, the hip, the acetabulum and the rib. In all cases, bone relapse was the first event, with one patient presenting a local relapse. Median time from the primary tumour and the evidence of bone relapse was 40 months (range 0–58). In 2/6 patients bone metastasis was treated with radiotherapy (RT), in 2/6 with surgery, in 2/6 with surgery plus RT. At a median follow-up of 55 months (range 23–88), 5/6 patients are alive (2/5 without disease, 3/5 with multicentric metastatic disease) and one is dead of disease. 2/6 patients did not relapse after the treatment of the bone metastasis.

Conclusions

This small series in a relatively rare histology suggests that isolated, possibly late, bone metastases are a plausible scenario, in particular in meningeal SFT. Notably, new bone lesions in a patient with a history of SFT should be always investigated. Exclusive local treatments may be an option, though collection of such series would be needed to define the best treatment strategy.

A giant solitary fibrous tumor of the mesentery: a case report and literature review

We report on an extremely rare case of a giant solitary fibrous tumor (SFT) of the mesentery in a 65-year-old male who was admitted to our hospital because of lower abdominal pain and abdominal fullness. Computed tomography demonstrated a well-defined solid mass of 25 × 11 cm located in the lower abdomen, which was completely resected during surgery. Histopathologically, this lesion had a heterogeneous cell population, mainly comprising spindle cells with fibrous collagen proliferation, and various other cell populations exhibiting patternless growth. Immunohistochemically, the tumor revealed strong and diffuse staining for CD34, bcl-2, and vimentin, and a high mitotic index (seven mitoses per 10 high-power fields). We diagnosed this case as an SFT of the mesentery, which is unusual according to a PubMed search that reported only nine such cases. Our case may be the largest tumor reported to date, and only one retrieved case reported recurrence, although the lesion was exceptionally large with deep invasion. Nonetheless, the lesion in our case was larger than that in the reported case of recurrence and invasive to the ileum. Since surgery, there has been no evidence of recurrence. Hence, we propose that a large SFT and high mitotic index may present risk factors for recurrence. Therefore, long-term careful follow-up is necessary in such cases, although our case exhibited few risk factors for recurrence. A follow-up at 12 months after surgery found no indications of recurrence.

Solitary fibrous tumor of the submandibular region

Solitary fibrous tumors (SFTs) are a rare type of neoplasm that originate from the pleura. Although SFTs may occur in a variety of extrathoracic regions, they are considered to be rare in the submandibular region. The current study presents the case of a 39-year-old female with a 3×4-cm, fibro-elastic, movable, painless nodule in the right side of the submandibular region. The patient exhibited no other clinical manifestations in the head and neck region. A computed tomography scan demonstrated the presence of a well-defined, slightly low-density nodular shadow measuring 2.6×3.3×3.8 cm, in proximity to the right submandibular gland, with mild contrast enhancement and no association with the adjacent lymph nodes. The lesion was surgically excised, and following histopathological and immunohistochemical analysis, immunohistochemical staining determined that the lesion was positive for cluster of differentiation (CD)34, CD99 and vimentin, and negative for desmin, CD31 and S-100; therefore, a diagnosis of an SFT was determined. The patient has so far been followed up for 22 months, with no signs of recurrence or metastases. The present study also discusses the clinical, histopathological and immunohistochemical features, treatment strategies and potential clinical outcomes of SFTs. The study proposes that, although rare, SFTs of the submandibular region should be included in the differential diagnosis of soft-tissue tumors in the submandibular region.

Desmoid-type fibromatosis of the mesentery: report of a sporadic case with emphasis on differential diagnostic problems

Desmoid-type fibromatosis is a rare mesenchymal neoplasm with local aggressiveness. The incidence of desmoid-type fibromatosis is 2-5/million/year with intra-abdominal fibromatosis, such as that which is reported in this clinical case, occurring only in 12-18% of cases. After having analyzed the pathogenetic hypotheses of desmoid-type fibromatosis, the authors point out that the diagnosis of this disease, especially in the intra-abdominal form, is often late, specifically when highly demolitive interventions are needed or when the limits of radical surgery have been exceeded. In the clinical case reported, the tumor was infiltrating both ileus and sigma. The authors consider the differential diagnosis of desmoid-type fibromatosis, especially with GISTs, with regard to both the radiological preoperative diagnostic and histological studies on the surgical specimen. Radical surgical excision is not always, for this disease, a sign of healing; in fact, even when the resection margins are negative, the incidence of recurrence is between 13 and 68%. The average time of recurrence is between 15 and 24 months; in this case report, the patient, who has not been subjected to complementary therapies, is tumor-free for over 30 months since surgery; his prognosis may be satisfactory if we consider the negativity of resection margins, which in any case remains the most important prognostic factor.

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.

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.

Pediatric Renal Solitary Fibrous Tumor

Solitary fibrous tumors (SFTs) are unusual spindle cell neoplasms initially described in the pleura but have since been discovered in many extrapleural locations. SFT of the kidney is extremely rare, the majority occurring in middle-aged adults. To date, only two pediatric cases of renal SFT have been reported. We report a case of large SFT in the kidney of a 3-year-old boy that was clinically and radiologically thought to be a nephroblastoma. This case is the first pediatric renal SFT to be reported with detailed histopathologic and cytogenetic analyses. SFT should be included in the differential diagnosis of pediatric renal tumors.

Solitary fibrous tumor of the kidney: a case report

Solitary fibrous tumor is a spindle cell neoplasm mostly originating from pleura; however, it has also recently been reported to be extrapleural. A 57-year-old man presented with left lumbal pain. Ultrasonography and computed tomography showed a cystic lesion of 14 × 11 cm with solid areas and septations in middle and lower poles of the left kidney. Radical nephrectomy was performed. Immunohistochemical studies showed strong reactions with CD34 and CD99. A nuclear positivity with Ki-67 was observed in less than 1% of cells. Despite repeated stainings with vimentin, no clear tumor evaluation could be made due to artifacts. The tumor was negative with Bcl-2, desmin, HMB-45, S100, FVIII, and CD31. Histopathological and molecular studies made the diagnosis of a solitary fibrous tumor. The patient is now currently free of disease at the 26th month of followup.

Response to chemotherapy of solitary fibrous tumour: a retrospective study

BACKGROUND

To report on anthracycline-based chemotherapy in a retrospective case-series analysis of solitary fibrous tumour (SFT) patients treated within the Italian Rare Cancer Network.

PATIENTS AND METHODS

We reviewed a set of SFT treated with chemotherapy since 2002, focusing on anthracycline, administered alone or in combination with ifosfamide. Responses to ifosfamide as a single agent were also evaluated. Pathologic diagnosis was centrally reviewed, distinguishing typical, malignant (MSFT) and dedifferentiated (DSFT) subtypes.

RESULTS

Among 42 SFT patients treated with chemotherapy, we selected 31 cases (mean age: 62 years; locally advanced/metastatic: 13/18; front-line/further line: 25/6; typical/MSFT/DSFT/not assessable: 1/17/12/1) who received anthracycline-based chemotherapy (anthracycline monotherapy: eight; anthracycline+ifosfamide: 23). 30 patients are evaluable for response. Best response by Response Evaluation Criteria in Solid Tumours (RECIST) was: partial response (PR): 6 (20%), stable disease (SD): eight (27%), progressive disease (PD): 16 (53%) cases. Responses were confirmed after 3 months. Median progression-free survival (PFS) was 4 (range 2-15) months, with 20% of patients being progression-free at 6 months. PR was found in 2/18 (11%) MSFT and 4/12 (30%) DSFT, with a median PFS of 3.5 and 5 months in MSFT and DSFT, respectively. 19 patients received high-dose prolonged-infusion ifosfamide (front-line/further line: 11/8; typical/MSFT/DSFT: 0/15/4) with two (10%) PR, five (26%) SD, 12 (63%) PD.

CONCLUSIONS

This retrospective series suggests that in SFT anthracyclines have a degree of antitumour activity in the range of soft tissue sarcoma chemotherapy. Ifosfamide monotherapy seemed to have lower activity. A higher response rate was observed in DSFT in comparison to MSFT. Studies on targeted therapies are ongoing.

Distant metastasis from benign solitary fibrous tumor of the kidney

Solitary fibrous tumor (SFT) rarely occurs in the kidneys, and only one reported case of renal SFT has shown distant metastasis. We report the second case of renal SFT exhibiting distant metastasis. A 48-year-old man was referred to our hospital because of a right renal mass. An abdominal CT scan detected a large renal tumor, which was suspected to be a renal cell carcinoma. Right radical nephrectomy was performed, and the tumor was found to measure 28 × 18 × 10 cm. The pathological diagnosis was benign solitary fibrous tumor of the kidney. Eight years after the operation, lung and liver metastases developed. Pulmonary segmentectomy and partial hepatectomy were performed. The pathological diagnoses of these resected tissue specimens were compatible with benign SFT.

Malignant solitary fibrous tumor of the kidney: report of the first case managed with interferon

Solitary fibrous tumors of the kidney are extremely rare tumors with unpredictable behavior. We describe a case of a patient with a solitary fibrous tumor of kidney with malignant findings with distant metastasis and nephrectomy managed with subcutaneous interferon achieving 23 months of progression-free survival. To date there is no prospective evaluation of any specific modality of treatment, but the surgical management and long-term followup are the only ones so far recommended strategies in the management of these patients. Studies are awaited with more patients to evaluate the different strategies of systemic therapy reported so far to allow adding survival benefit.

Sunitinib malate in solitary fibrous tumor (SFT)

BACKGROUND

To report on sunitinib activity in a retrospective series of 35 solitary fibrous tumor (SFT) treated at a single institution.

PATIENTS AND METHODS

From April 2008, 35 patients with progressive advanced SFT (male/female: 20/15; mean age: 58 years; meningeal/extrameningeal: 6/29; locally advanced/metastatic: 15/20; prior chemotherapy: 25) were treated, on an individual use basis, with continuous-dosing sunitinib 37.5 mg/day. Platelet-derived growth factor receptor beta (PDGFRB) and vascular endothelial growth factor receptor 2 (VEGFR2) status were assessed by immunohistochemistry and, in a subgroup of patients, by real time PCR.

RESULTS

Thirty-one patients were assessable for response by RECIST (one early death; three early interruptions). Best responses were 2 partial response (PR), 16 stable disease, 13 progressive disease. A <30% decrease in size was observed in three patients. Fourteen of 29 patients assessable by Choi criteria had a PR. Median progression-free survival by RECIST was 6 months (range 1-22). In two of six patients, resistance to sunitinib was overcome by increasing sunitinib to 50 mg/day. PDGFRB and/or VEGFR2 were positive in all cases and not predictive of response; a less aggressive morphology corresponded to an increased response rate (53% PR by Choi in the malignant SFT, 20% PR in the pleomorphic/dedifferentiated SFT).

CONCLUSIONS

Sunitinib is active in SFT. Response can be long-lasting.

Unclassified pediatric renal stromal tumor overlapping with metanephric stromal tumor and solitary fibrous tumor with diffuse S-100 protein expression

Metanephric stromal tumor (MST) is a rare pediatric neoplasm unique to the kidneys that is currently included in the spectrum of metanephric tumors, along with metanephric adenoma and adenofibroma. We herein report an unusual case of pediatric renal stromal tumor overlapping with MST and solitary fibrous tumor (SFT). Histologically, the tumor was composed of bland-looking spindle to stellate cells embedded in a fibro-sclerotic stroma that focally surrounded native entrapped renal tubules or blood vessels with abortive rings or collarettes. Alternating hypercellular and hypocellular areas and a focal hemangiopericytomatous-like vascular pattern imparted to the tumor a resemblance to SFT. Angiodysplasia of intratumoral arterioles was also observed, but juxtaglomerular cell hyperplasia was not a feature. Immunohistochemically, the neoplastic cells showed a polyphenotypic profile, including diffuse expression of vimentin and CD34, and focal immunoreactivity for alpha-smooth muscle actin, EMA, and CD99. However, the most striking finding was diffuse nuclear and cytoplasmic expression of S-100 protein. Although this protein has been reported to stain the heterologous glial and/or cartilaginous components that can be occasionally encountered in MST, this marker has not been previously reported in the fibroblastic component of MST. Pathologist should be aware of similar unusual unclassified tumors to avoid potential confusion with other benign or malignant S-100 protein-positive tumors.

De novo malignant solitary fibrous tumor of the kidney

The kidney is a relatively infrequent site for solitary fibrous tumor (SFT). Among the previously reported cases, only two cases of malignant renal SFT developing via dedifferentiation from a pre-existing benign SFT have been reported. Here we reported a case of de novo malignant renal SFT clinically diagnosed as renal cell carcinoma in a 50-year-old woman. The tumor was circumscribed but unencapsulated and showed obvious hemorrhagic necrosis. Microscopically, the tumor was composed of patternless sheets of alternating hypercellular and hypocellular areas of spindle cells displaying mild to moderate nuclear atypia, frequent mitoses up to 8 per 10 high power fields, and a 20% Ki-67 proliferative index. Immunohistochemical studies revealed reactivity for CD34, CD99 and vimentin, with no staining for all other markers, confirming the diagnosis of SFT. No areas of dedifferentiation were seen after extensive sampling. Based on the pathologic and immunohistochemical features, a diagnosis of de novo malignant renal SFT was warranted. Our report expands the spectrum of malignant progression in renal SFTs. Even though this patient has been disease-free for 30 months, long-term follow-up is still mandatory.

Somatic and visceral solitary fibrous tumors in the abdomen and pelvis: cross-sectional imaging spectrum

Solitary fibrous tumors (SFTs) are a unique group of mesenchymal neoplasms of fibroblastic or myofibroblastic origin. These tumors were originally described as "benign fibrous mesotheliomas" of the pleural cavity and were erroneously thought to be confined to the serosal surfaces (due to a putative mesothelial or submesothelial origin). It is now established that SFTs are ubiquitous neoplasms with both pleural and extrapleural distribution. Extrapleural SFTs commonly occur in middle-aged adults and manifest as asymptomatic, slow-growing, large tumors. Fewer than 5% of patients with SFTs present with symptomatic hypoglycemia. SFTs are histopathologically diverse with a variable admixture of fibroblasts or myofibroblasts, numerous thin-walled vessels, and dense fibrosis. Tumors previously categorized as hemangiopericytomas are now considered cellular variants of SFTs. At imaging, SFTs demonstrate remarkable heterogeneity, with variable degrees of enhancement, necrosis, or hemorrhage. Although most extrapleural SFTs have a benign clinical course, 10%-15% of these tumors demonstrate aggressive behavior in the form of recurrence or malignancy.

Pediatric and adult primary sarcomas of the kidney: a cross-sectional imaging review

There is a wide pathological spectrum of kidney sarcomas that show characteristic histology, ontogeny, and clinical-biological behavior. While leiomyosarcomas commonly arise from the capsule, solitary fibrous tumors and clear cell sarcomas typically show renal sinus and medullary epicenter, respectively. Although distribution and imaging findings of some sarcomas may be characteristic, definitive diagnosis warrants histopathological examination following surgery. Renal sarcomas manifest advanced disease at presentation and portend poor prognosis.

Dedifferentiated Endometrioid Adenocarcinoma of the Uterus

Dedifferentiation confers more aggressive malignant behaviour than would be otherwise shown by the original tumor if present alone. This phenomenon has been described in several tumors, both mesenchymal and epithelial. Dedifferentiated endometrioid carcinoma either ovarian or endometrial is the latest addition to this family of tumors. Only 2 papers have appeared in the literature so far on the topic of dedifferentiated endometrioid carcinoma, both from the same institution. We report herein a case of endometrial dedifferentiated endometrioid carcinoma in a 45-year old lady with ovarian metastasis from the undifferentiated component. The primary endometrial tumor showed an undifferentiated component in an otherwise low grade endometrioid carcinoma. The undifferentiated component of these tumors can be misdiagnosed as the solid component of FIGO grade 3 in a pure endometrioid carcinoma. The recognition of an undifferentiated component in an otherwise low grade endometrioid carcinoma is very important, since dedifferentiated endometrioid adenocarcinoma has a worse prognosis when compared with FIGO grade 3 endometrioid carcinoma.