Retroperitoneal solitary fibrous tumor: surgery as first line therapy

Solitary Fibrous Tumor Requiring Abdominal Aortic Vessel Replacement

Solitary fibrous tumors (SFTs) are mesenchymal tumors, and retroperitoneal occurrence is rare. It has been identified in a variety of soft tissues and organs, such as the pleura, peritoneum, and meninges. In this case, the tumor was in contact with the abdominal aorta, and the invasion was difficult to judge preoperatively. Intraoperatively, it was revealed that the tumor could not be completely removed without aortic replacement. Although SFTs have a generally good prognosis, certain factors, such as tumor incomplete resection, have been reported to increase the risk of recurrence and metastasis. We were able to completely remove the tumor by performing a combined resection of the aorta. The specimens were microscopically disorganized proliferation of spindle-shaped cells. Immunostaining was positive for cluster of differentiation 34 (CD34) and signal transducer and activator of transcription 6 (STAT6). The tumor cells infiltrating into aortic adventitia were observed. This is a valuable case in which artificial blood vessel replacement was able to reduce the risk of recurrence and metastasis due to tumor remnants. We report a rare case of SFT resected with artificial blood vessel replacement.

Case report: A huge retroperitoneal solitary fibrous tumor closely related to the external iliac vessels misdiagnosed as an ovarian tumor

Background

Solitary fibrous tumor (SFT) is a rare soft tissue tumor originating from mesenchymal cells. Thus far, there have been no reported cases of SFT closely related to the iliac vessels.

Case presentation

An elderly woman was found to have had a lower abdominal mass for more than 20 years. The enhanced computerized tomography (CT) showed a progressively enhanced hypervascular mass. The external iliac blood vessels were closely related to the mass, which was misdiagnosed as an ovarian tumor. During laparotomy, the external iliac vein was seen to penetrate the tumor, and the external iliac artery was seen to penetrate the tumor capsule. The retroperitoneal tumor was diagnosed during the operation. The surgical plan of complete tumor resection, severing of the external iliac arteries and veins, and blood vessel replacement was implemented. Pathological immunohistochemistry showed positive results for STAT6 and CD34, confirming the diagnosis of giant retroperitoneal SFT. The risk is classified as high and requires long-term follow-up. There has been no local recurrence or distant metastasis almost 1 year after surgery.

Conclusion

The incidence of giant retroperitoneal SFT is rare, and the diagnosis can be confirmed through preoperative imaging examination and pathological examination. If the SFT capsule is intact, there is a chance of surgical resection. For SFTs that are penetrated by the iliac blood vessels, adequate preparation must be made before the surgery is performed. Removing the tumor and the iliac blood vessels at the corresponding site and then replacing it with artificial blood vessels is a feasible method with less risk of bleeding. In this case, imaging showed a progressively enhancing hypervascular mass in the lower abdomen, which was related to blood vessels. Preoperative biopsy and pathological testing can confirm the diagnosis. Neoadjuvant therapy or interventional therapy before surgery can shrink the tumor, making the surgical procedure relatively easy with less risk of bleeding.

Primary Omentum Malignant Hemangiopericytoma Present with Acute Abdomen

The greater omentum primary malignant tumors are rare, with less than 50 cases reported. Malignant hemangiopericytomas constitute only four of these cases. The common clinical manifestations of a malignant omental tumor are abdominal mass and pain. We report on a woman 38 years old who came to the hospital's emergency department with a finding consisting of intestinal obstruction (abdominal pain, constipation, abdominal distention, and vomiting), and during a clinical examination a mass was discovered in the lower half of her abdomen. She had been experiencing these symptoms for three days before her arrival. During a clinical examination, a large size, hard mobile mass was discovered in the lower half of her abdomen. The patient underwent an abdominal CT scan which indicated the presence of a sizable, soft tissue mass located within the abdominal and pelvic region, exerting pressure on the small bowel loops, with mild free ascites. Due to the patient's acute abdomen, an exploration laparotomy was performed, revealing a large mass in the omentum measuring 20×20×10 cm and weighing 3 kg. The mass, along with the omentum, was completely removed, and histopathology confirmed a malignant hemangiopericytoma.

Solitary fibrous tumor in the retroperitoneum: A case report

INTRODUCTION AND IMPORTANCE

Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor that can manifest in a variety of locations, including the retroperitoneum. The most effective standard diagnostic approach and treatment is yet to be determined due to unpredictable behavior of SFT, including retroperitoneal SFT.

CASE PRESENTATION

A 43-year-old female with a retroperitoneal SFT presented with a palpable mass and symptomatology. Surgical exploration disclosed a tumor encompassing the left renal artery and vein, necessitating left nephrectomy and retroperitoneal mass removal. Initial histological examination suggested rhabdomyosarcoma, but subsequent immunohistochemistry confirmed the diagnosis of retroperitoneal SFT. No adjuvant therapy was administered, and there was no detectable mass on follow-up imaging. The patient remained symptom-free.

CLINICAL DISCUSSION

Retroperitoneal SFTs are difficult to diagnose due to their non-specific morphology, thus immunohistochemistry plays a crucial role in confirming its diagnosis. Surgical excision with negative resection margins continues to be the standard treatment. Recurrence rates are low in comparison to other retroperitoneal sarcomas, hence routine chemotherapy or radiation therapy is not advised.

CONCLUSION

This case demonstrates the significance of contemplating SFT as the differential diagnosis of retroperitoneal tumors and the role of immunohistochemistry in confirming the diagnosis. The optimal management strategies for retroperitoneal SFTs should be determined by additional research.

Malignant retroperitoneal solitary fibrous tumor co-existing with Meigs' syndrome: A case report

Malignant solitary fibrous tumors in the retroperitoneum are rare, and their treatment strategies have not yet been established. A 61-year-old woman with dyspnea underwent laparotomy under a presumptive diagnosis of Meigs' syndrome. She underwent both adnexectomy and retroperitoneal tumor excision. The histologic diagnosis was of a fibrothecoma of both ovaries and a retroperitoneal solitary fibrous tumor that was considered malignant based on its mitotic activity. Local recurrence was observed 9 months postoperatively; re-excision was performed, and radiation therapy was administered. Four months later, metastasis to the left lung was detected, and a thoracoscopic resection was performed. Although pazopanib was administered subsequently, it was discontinued after 11 months because of proteinuria. She complained of dysphagia 3 weeks after the withdrawal of the drug, and a metastatic tumor was observed at the cranial base. Radiotherapy was initiated; however, she died of the disease 35 months after the primary surgery. Medical guidelines should be established for malignant solitary fibrous tumors to improve patient prognosis.

Primary retroperitoneal solitary fibrous tumor: A case report

Primary retroperitoneal masses have numerous differential diagnoses, many of which are rare entities. These can be neoplastic or nonneoplastic. Among the rare conditions are solitary fibrous tumors, which can either be benign or malignant. It is a mesenchymal, spindle-cell tumor, reported first in 1931 as a pleural tumor by Klemperer et al. A 20-year-old lady, with abdominal pain for 6 months, was diagnosed with a retroperitoneal mass on the left lower abdomen on USG which was confirmed by an MRI scan of the abdomen. The patient underwent laparoscopy-assisted excision of the mass. The final histopathological reports and immunohistochemistry reports revealed a solitary fibrous tumor. Solitary fibrous tumors (SFTs) are rare tumors in the retroperitoneum. In our search, fewer than a hundred cases have been reported. It has a characteristic "patternless pattern" in a microscopic study. Adverse outcomes of SFTs are associated with atypical features in histology, such as nuclear pleomorphism, necrosis, increased cellularity, and mitoses >4/10 HPF and size more than 10 cm. The standard of care is surgical excision with clear margins. Open surgeries have been done traditionally; we present a case where we performed the excision laparoscopically.

CT of retroperitoneal solitary fibrous tumor

Solitary fibrous tumors are rare tumors of pluripotent fibroblastic or myofibroblastic origin that generally arise among older individuals, with a mean age of onset ranging from 55 to 65 years. Though typically associated with pleural involvement, solitary fibrous tumors can emerge in virtually every anatomic location within the body. Although most solitary fibrous tumors are benign, approximately 20% may exhibit malignant features such as local invasion, recurrence, and metastases. In this article, we report the case of a 58-year-old male with a diagnosis of a retroperitoneal solitary fibrous tumor. We analyze computed tomography imaging findings and additionally correlate imaging features with the patient's unique pathological and genotypic findings to optimize diagnosis.

The Landscape of Immunotherapy for Retroperitoneal Sarcoma

Significant multidisciplinary scientific effort has been undertaken to understand the heterogeneous family of neoplasms that comprise soft tissue sarcomas. Within this family of neoplasms, outcomes for retroperitoneal sarcomas (RPS) are currently limited given a lack of effective therapies. In this review, we focus on immunotherapy and its relationship with the common RPS histologic subtypes. Although initial outcomes for RPS patients with immune checkpoint inhibition alone have been somewhat disappointing, subsequent analyses on histologies, the tumor microenvironment, sarcoma immune class, tumor infiltrating lymphocytes and genetic analysis for tumor mutational burden have yielded insight into the interplay between sarcomas and immunotherapy. Such approaches have all provided critical insight into the environment and characterization of these tumors, with targets for potential immunotherapy in future clinical trials. With this insight, molecularly tailored combination treatments for improving response rates and oncologic outcomes for RPS are promising.

Angiomyofibroblastoma and Potential Mimicking Soft Tissue Tumors That May Occasionally Present in the Retroperitoneum: An Approach to the Differential Diagnosis With Report of an Unusual Index Case Abutting the Kidney

The retroperitoneal soft tissues, extending from the pelvic floor to the level of the diaphragm, are the source of a variety of mesenchymal neoplasms with overlapping features and distinct clinical behaviors, making their distinction of crucial importance. Herein, we report a rare retroperitoneal angiomyofibroblastoma (AMFB) that presented as a right abdominal mass in a 25-year-old woman and that clinically simulated a primary renal carcinoma. The patient underwent complete surgical resection showing a well-circumscribed tumor adjacent to but separate from the right kidney. It was comprised of irregular, often anastomosing islands and cords of plump to spindled cells in a collagenous stroma with numerous thin-walled vessels. The tumor cells clustered around the vessels and admixed with moderate numbers of adipocytes. There was neither significant nuclear atypia nor mitotic activity. Immunohistochemically, the tumor cells showed strong reactivity for desmin, diffuse expression of estrogen and progesterone receptors, retained nuclear expression of retinoblastoma protein, and absent CD34 expression. The immunomorphological features were these of a "lipomatous variant" of AMFB of the retroperitoneum. The occurrence of AMFB in the retroperitoneum is unexpected since it mostly develops in the lower genital tract of young women, making its recognition in this rare location difficult. As a consequence, more common pelvic or retroperitoneal soft tissue neoplasms may represent the primary diagnostic considerations. We, therefore, review a variety of soft tissue tumors occurring in the pelvis/retroperitoneum that, to some degree, may mimic AMFB, and present key findings to assist in accurate diagnosis.

Postoperative Morbidity After Radical Resection of Retroperitoneal Solitary Fibrous Tumor

BACKGROUND

This study aimed to investigate the clinicopathological characteristics of retroperitoneal solitary fibrous tumor (RSFT) and the safety of radical resection.

METHODS

A retrospective analysis was conducted on the data of 32 RSFT patients who received surgery with curative intent from February 2011 and June 2021.

RESULTS

This cohort included 16 (50%) male and 16 (50%) female patients, with the median age of 52 (29 to 72) years. Tumor burden ranged from 3 to 25 (median, 10) cm. Seven patients received arterial embolization before surgery. 15 (47%) patients received radiotherapy, nine (28%) of which received preoperative radiotherapy. Most of the patients (91%) achieved complete resection with median bleeding of 400 (20 to 5,000) ml. Nine (28%) patients received packed red blood cell (RBC) transfusion, with a median of 5 (2 to 10) U. All patients had the five-year progression-free survival rate and the overall survival rate of 75.8% and 80.0%, respectively. 11 (34%) patients were found with adverse events, and four (12%) patients were found with serious postoperative complications (Clavien-Dindo ≥3), of which one (3.1%) patient died after surgery. The univariate analysis found that tumor burden (p = 0.022), packed RBC transfusion (p = 0.001) and postoperative hospital stays (0.027) were correlated with overall morbidity. The multivariate analysis found packed RBC transfusion as an independent risk factor for postoperative morbidity (HR 381.652, 95% CI, 1.597-91213.029, p = 0.033).

CONCLUSION

RSFT was confirmed as an uncommon, slow-growing and recurring tumor, with acceptable postoperative morbidity and mortality after surgical resection.

Solitary Fibrous Tumor of Adrenal Gland and Review of the Literature

Solitary fibrous tumor (SFT) is a rare and still controversial entity. This type of tumor first appeared in the literature as a pleural lesion, but, over the last decades, it has been reported in many extrathoracic sites. As a tumor of the adrenal gland, SFT is still rare and very uncommon, thus extensive research among the English language literature has been performed. We present here a case report of an adrenal SFT which is compared to 11 other known cases. Our case report is from a patient with SFT on the left adrenal gland, followed by mild symptoms of abdominal discomfort and hypertension. Physical examination, laboratory, and radiological tests were performed. The patient underwent surgery and the material was sent for histopathologic analysis for a definite diagnosis. Regular follow up appointments were performed over the course of two years. No recurrence of the tumor has been detected. We explain the symptoms, diagnosis, treatment, and additionally we describe the results and implications of the findings reported in the literature. Correct diagnosis is mandatory for optimal management of solitary fibrous tumor patients.

Radiologic-Pathologic Correlation of Primary Retroperitoneal Neoplasms

An earlier incorrect version of this article appeared in print. The online version is correct.

Intrapericardial solitary fibrous tumor: A case report and review of literature

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm mostly originates from pleura, but rarely from other parts of the body including pericardium. We report a case of a 44-year-old woman with dyspnea and intermittent edema in whom a large intrapericardial mass was discovered by echocardiography. Computed tomography (CT) revealed a focal pericardial calcification in right AV grove with pressure on right ventricle and right atrial, with no connection to cardiac chambers. Histopathological findings after complete resection of the mass revealed fibroconnective tissue with heavy calcification and no evidence of inflammation or malignancy. We reviewed the literature on pericardial solitary fibrous tumors up to 2020.

Malignant haemangiopericytomas of omentum presenting as left inguinal hernia: A case report

Background

Hemangiopericytomas (HPC) are vascular tumors and can be found at any place where vessels are present. These were previously known as ‘extrapleural Solitary Fibrous Tumour’. These tumors may reoccur and metastasize after surgical excision. We present herein a HPC of the greater omentum, diagnosed as left inguinal hernia preoperatively.

Case presentation

A 61-year-old male, presented with a huge painless mass in his left inguinoscrotal region secondary to weigh-lifting associated with malaise and vague abdominal pain. A well-defined, non-tender, and firm mass was found at the left lower abdomen extending to the left inguinoscrotal region. Based on the examination, a diagnosis of indirect inguinal hernia was made. Abdominal ultrasound showed a heterogeneous, hyporeflective, and vascularized mass. Contrast-enhanced computed tomography scan identified a localized, extraperitoneal, heterogeneously hypodense, well-defined, and lobulated mass, with marked contrast enhancement. On exploration, an encapsulated large mass originating from the omentum with enormously dilated blood vessels was excised. On histopathology, a neoplastic lesion, composed of spindle-shaped cells and moderate cytoplasm was identified. The blood vessels appeared thin-walled with a staghorn appearance in hemangiopericytic pattern. Omental sections showed fibro adipose tissue with dilated lymphatics and thick-walled blood vessels. Features were consistent with a malignant HPC of 20 × 14 × 10 cm.

Conclusion

We present an unusual presentation of primary omental malignant HPC as an inguinal hernia, treated by complete surgical resection. These tumors are rare therefore, timely diagnosis is important for proper evaluation, diagnosis, and treatment. It also requires long-term follow up for better survival.

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Hemangiopericytoma (HPC), previously known as ‘extrapleural Solitary Fibrous Tumor’, is a vascular tumor.

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A well-defined, non-tender, and firm mass was found at the left lower abdomen extending to the left inguinoscrotal region.

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Based on the examination, a diagnosis of indirect inguinal hernia was made.

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CT scan showed a contrast enhancing, localized, extraperitoneal, heterogeneously hypodense, and lobulated mass.

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On exploration, an encapsulated large mass originating from the omentum with enormously dilated blood vessels was excised.

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On histopathology, features were consistent with a malignant HPC of 20 × 14 × 10 cm.

Strategies for care of patients with gastrointestinal stromal tumor or soft tissue sarcoma during COVID-19 pandemic: A guide for surgical oncologists

The coronavirus disease-2019 (COVID-19) pandemic is deeply impacting the accessibility of cancer patients to surgery. In resource-limited conditions, the standard of care might not be deliverable, but evidence to support alternative management strategies often exists. By revisiting available treatment options, this review provides surgical oncologists with an evidence-based framework for treating patients with gastrointestinal stromal tumor, extremity/truncal soft tissue sarcoma, and retroperitoneal sarcoma to rapidly adapt their decision-making to the constant evolution of the COVID-19 pandemic.

Soft-tissue sarcoma in adults: An update on the current state of histiotype-specific management in an era of personalized medicine

Soft-tissue sarcomas (STS) are rare tumors that account for 1% of all adult malignancies, with over 100 different histologic subtypes occurring predominately in the trunk, extremity, and retroperitoneum. This low incidence is further complicated by their variable presentation, behavior, and long-term outcomes, which emphasize the importance of centralized care in specialized centers with a multidisciplinary team approach. In the last decade, there has been an effort to improve the quality of care for patients with STS based on anatomic site and histology, and multiple ongoing clinical trials are focusing on tailoring therapy to histologic subtype. This report summarizes the latest evidence guiding the histiotype-specific management of extremity/truncal and retroperitoneal STS with regard to surgery, radiation, and chemotherapy.

Outcome of patients with primary retroperitoneal solitary fibrous sarcoma

BACKGROUND

To describe the clinicopathological features of primary retroperitoneal solitary fibrous tumor (RSFT) and define the prognostic factors.

METHODS

The comprehensive data of 35 primary RSFT patients who got curative surgery at a tertiary cancer center from April 2004 to October 2018 were retrospectively analyzed.

RESULTS

Male patients outnumbered female patients (19 vs. 16), with the age ranging from 19 to 73 years (median, 51 years). 7 (20%) patients had tumors located in special parts, including three in kidney, one in renal pelvis, one in bladder, one in prostate, and one in mesentery. Tumor sizes ranged from 2.5 to 25 cm (median, 9 cm). Microscopic negative margin was reached in 33 (94.3%) cases. 13 (37.1%) were classified as atypical/malignant, while 22 (62.9%) were benign. Concomitant organ excision was performed on 11 (31.4%) patients, with kidney (n = 5) being the most frequent organ. Multifocality was only found in 4 (11.4%) cases. The majority of the patients (31, 88.6%) did not get adjuvant treatment. The median follow-up time was 46 months (range 4-153 months). The 5-year DSS rate and DFS rate were 100% and 63.6%, respectively. In univariate analysis, tumor size ≥ 10 cm (P = 0.002) and atypical/malignant pathology (P = 0.024) were associated with decreased DFS. Multivariate analysis revealed that tumor size was the only independent prognostic factor for DFS (HR 6.03, 95% CI 1.18-30.77, P = 0.031).

CONCLUSION

RSFT is uncommon, slow-growing, and recrudescent tumors. Large tumor size and malignant pathology are associated with decreased DFS. Tumor size ≥ 10 cm independently predicts shortened DFS.

Primary omental malignant solitary fibrous tumour, an extremely rare malignancy: A case report and review of the literature

Primary omental malignant solitary fibrous tumour is an extremely rare neoplasm considering its tumour origin and pathologic characteristics. Solitary fibrous tumour (SFT) is a spindle cell neoplasm that was first described in 1931. SFT is diagnosed at immunohistochemical stain including CD34, bcl2, CD99 and STAT6. Though most of SFTs are benign in nature, 5-15% are malignant. The diagnostic criteria of malignant SFTs are high cellularity, high mitotic activity(>4/10HPF), pleomorphism, necrosis and haemorrhage. We present the case of a 57-year-old male patient diagnosed with primary omental malignant SFT. Neither tumour origin nor pathologic diagnosis were possible based on preoperative information. Nevertheless, tumour resection was performed successfully. Several SFT cases involving omentum without malignant potential have been reported. However, primary omental malignant SFTs are extremely rare with only 3 cases reported in the literature.

Solitary fibrous tumor mimicking adrenal tumor concomitant with contralateral adrenal pheochromocytoma: A case report of surgical resection after long-term observation

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The management of bilateral adrenal masses is sometimes challenging.

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Adrenal mass was enlarged after contralateral adrenalectomy for pheochromocytoma.

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SFT is a rare cause of adrenal mass and its long-term natural history remains unknown.

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Surgical resection of SFT with partial adrenalectomy is a preferred choice.

Introduction

Solitary fibrous tumors (SFT) usually originate from the pleura and rarely occur in the retroperitoneum. There were few reports of SFT around the adrenal gland and its long-term clinical behavior remains unknown.

Presentation of case

A 62-year-old woman with bilateral adrenal tumors was referred to our department in 2008. She had elevated urinary normetanephrine. Metaiodobenzylguanidine scintigraphy showed uptake in the right adrenal gland. The tumor in the right adrenal gland was 5 cm in diameter. The patient underwent right adrenalectomy and was diagnosed with pheochromocytoma. The left tumor was 3 cm in diameter and diagnosed as benign using imaging. However, its size gradually increased to 10 cm over 7 years after surgery. The catecholamine hormones were within normal range. The patient underwent the tumor resection and left partial adrenalectomy. A steroid cover was given temporarily after surgery for prophylactic purposes. The histological diagnosis was solitary fibrous tumor. There was no recurrence 2 years after surgery.

Discussion

There have been only nine case reports of SFTs that were diagnosed as adrenal tumor by clinical imaging in the English literature. Total adrenalectomy was performed in all patients with a unilateral tumor. One patient with bilateral tumors underwent partial adrenalectomy.

Conclusion

SFT in the periadrenal region is difficult to differentiate from adrenal tumor. However, tumor resection with partial adrenalectomy should be considered for enlarged tumor with less aggressive behavior in patients with a history of contralateral adrenalectomy.

Extrapleural solitary fibrous tumor: A distinct entity from pleural solitary fibrous tumor. An update on clinical, molecular and diagnostic features

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that was originally described to be localized in the pleura, but thereafter, this has been reported in several anatomic sites. Although the etiology of the neoplasm remains largely unknown, the pathogenesis seems to be related to an NAB2-STAT6 fusion gene due to paracentric inversion on chromosome 12q13. The diagnosis of extrapleural SFT is challenging, owing to its rarity, and requires an integrated approach that includes specific clinical, histological, immunohistochemical, and even molecular findings. Histologically, extrapleural SFT shares morphological features same as those of the pleural SFT because it is characterized by a patternless distribution of both oval- and spindle-shaped cells in a variable collagen stroma. In addition, morphological variants of mixoid, fat-forming, and giant cell-rich tumors are described. A correct diagnosis is mandatory for a proper therapy and management of the patients with extrapleural SFT, as extrapleural SFT is usually more aggressive than pleural form, particularly cases occurring in the mediastinum, retroperitoneum, pelvis, and meninges. Although SFT is usually considered as a clinically indolent neoplasm, the prognosis is substantially unpredictable and only partially related to morphological features. In this context, cellularity, neoplastic borders, cellular atypias, and mitotic activity can show a wide range of variability. We review extrapleural SFT by discussing diagnostic clues, differential diagnosis, recent molecular findings, and prognostic factors.

Management of the "Other" retroperitoneal sarcomas

The focus of this review is on the management of the less common sarcomas occurring in the retroperitoneal space, including solitary fibrous tumor (SFT), malignant peripheral nerve sheath tumor (MPNST), perivascular epithelioid cell tumor (PEComa), and undifferentiated pleomorphic sarcoma (UPS) of the psoas muscle. As for other retroperitoneal sarcomas, surgical resection is the mainstay of curative therapy, and multidisciplinary preoperative assessment, including percutaneous needle biopsy for histologic confirmation, is the basis for personalized management, as the surgical management, and the integration of systemic therapy and radiation therapy is unique to each histologic subtype.

Overall survival after resection of retroperitoneal sarcoma at academic cancer centers versus community cancer centers: An analysis of the National Cancer Data Base

BACKGROUND

Operative resection remains the definitive curative therapy for retroperitoneal sarcoma. Data published recently show a correlation between improved outcomes for complex oncologic operations and treatment at academic centers. For large retroperitoneal sarcomas, operative resection can be complex and require multidisciplinary care. We hypothesized that survival rates vary between type of treating center for patients undergoing resection for retroperitoneal sarcoma.

METHODS

Patients with stage I to III nonmetastatic retroperitoneal sarcomas who underwent operative resection were identified from the National Cancer Database during the years 2004-2013. Treating centers were categorized as academic cancer centers or community cancer centers. Overall survival was analyzed by log-rank test and graphed using Kaplan-Meier method.

RESULTS

A total of 2,762 patients were identified. A majority of patients (59.4%, n = 1,642) underwent resection at an academic cancer centers. Median age at diagnosis was 63 years old. Neoadjuvant radiotherapy was more common at academic cancer centers, while adjuvant radiotherapy was more common at community cancer centers. Improved overall survival was seen at academic cancer centers across all stages compared with community cancer centers (P = .014) but, after multivariable Cox regression analysis, was not a significant independent predictor of survival (hazard ratio = 0.91, 95% confidence interval, 0.79-1.04, P = .171). Academic cancer centers exhibited a greater rate of R0 resection (55.9% vs 47.0%, P < .001) and a lesser odds of positive margins (odds ratio 0.83, 95% confidence interval, 0.69-0.99, P = .044) after multivariable logistic regression.

CONCLUSION

Resection for retroperitoneal sarcoma performed at academic cancer centers was an independent predictor of margin-negative resection but was not a statistically significant factor for survival. This observation suggests that site of care may contribute to some aspect of improved oncologic resection for retroperitoneal sarcoma.

Retroperitoneal Solitary Fibrous Tumor: A "Patternless" Tumor

Introduction

Solitary fibrous tumor is a rare type of mesenchymal, spindle-cell tumor reported mostly in the pleura. Retroperitoneal occurrence is rare and histopathological diagnosis is challenging.

Case Presentation

A 55-year-old woman with nonspecific abdominal pain was found to have a retroperitoneal/pelvic mass adjacent to the upper rectum. The patient underwent surgical resection in clear margins of this pelvic tumor, entering the total mesenteric excision surgical plane. Final histopathology revealed a solitary fibrous tumor and the case is presented herein.

Discussion

Solitary fibrous tumor in the retroperitoneum is rarely found in the literature and to the best of our knowledge less than a hundred cases are described so far. Histopathological diagnosis is mostly based on a “patternless pattern” on microscopic examination, which is a storiform arrangement of spindle cells combined with a “hemangiopericytoma-like appearance” and increased vascularity of the lesion. Surgery is the mainstay of treatment and recurrence rates are generally low.

Malignant solitary fibrous tumor in retroperitoneum: A case report and literature review

RATIONALE

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor occurs in various sites. Malignant SFT in retroperitoneum is extremely rare.

PATIENT CONCERNS

We report a case of malignant retroperitoneal SFT in a 59-year-old man presented with right flank pain for 1 month.

DIAGNOSES, INTERVENTIONS AND OUTCOMES

A laparotomy and resection of the tumor were performed, the histopathologic and immunohistochemical findings were consistent with malignant retroperitoneal SFT. No adjuvant treatment was performed, and the patient had no signs of recurrence or metastasis at the 12 months follow-up.

LESSONS

Complete surgical excision is the basic treatment principle for malignant retroperitoneal SFT. The histologic features and the Ki-67 label index are helpful for the diagnosis of malignant SFT.

Malignant Solitary Fibrous Tumor with Heterologous Rhabdomyosarcomatous Differentiation: A Case Report

Malignant solitary fibrous tumor (MSFT) is a well-described entity, from which heterologous differentiation is extremely rare. We encountered a case of MSFT with rhabdomyosarcomatous differentiation in a 56-year-old man. This patient presented with a large mass in his posterior thigh. He had been treated with chemoradiation for sarcoma involving the cervical spine, right femoral head, and both lungs 6 months earlier. A wide excision was performed. The mass measured 10.6 cm and showed a fish-flesh cut surface with necrotic foci. Microscopically, the tumor showed heterogeneous cellularity with a hemangiopericytic vascular pattern. A hypercellular area showed spindle cells or epithelioid cells with high mitotic activity (63/10 high-power fields) and immunoreactivity for CD34 and CD99. A hypocellular area and a cystic area showed pleomorphic rhabdoid cells with immunoreactivity for desmin and myogenin. This is a report of a rare case of MSFT with rhabdomyosarcomatous differentiation and presents new histologic features of MSFT.