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

Solitary fibrous tumor of the adrenal gland: a case report and review of the literature

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor, probably of fibroblastic origin, mainly in the extremities and pleura. Primary SFT of the adrenal gland is clinically more rare. Here, we report the case of a 47-year-old woman who detected a left adrenal mass on physical examination, without any symptoms, and no laboratory abnormalities. A computed tomography (CT) examination of the adrenal gland suggested a round-like soft tissue density shadow in the left adrenal area. An unenhanced scan showed uneven density of the mass, with a scattered circular-like cystic low-density shadow inside, and an enhanced scan showed obvious uneven enhancement. We considered it to be adrenal pheochromocytoma. Ultimately, the patient was treated with laparoscopic left adrenalectomy. A pathological examination suggested an adrenal SFT. We reviewed previous case reports of adrenal SFTs and summarized the clinical characteristics of adrenal SFT combined with the relevant literature. For adrenal tumors with uneven low-density shadow and uneven CT enhancement features, we should consider the differential diagnosis of adrenal SFT.

Non-gastrointestinal stromal tumor, mesenchymal neoplasms of the gastrointestinal tract: a review of tumor genetics, pathology, and cross-sectional imaging findings

There is a diverse group of non-gastrointestinal stromal tumor (GIST), mesenchymal neoplasms of the gastrointestinal (GI) tract that demonstrate characteristic pathology and histogenesis as well as variable imaging findings and biological behavior. Recent advancements in tumor genetics have unveiled specific abnormalities associated with certain tumors, influencing their molecular pathogenesis, biology, response to treatment, and prognosis. Notably, giant fibrovascular polyps of the esophagus, identified through MDM2 gene amplifications, are now classified as liposarcomas. Some tumors exhibit distinctive patterns of disease distribution. Glomus tumors and plexiform fibromyxomas exhibit a pronounced affinity for the gastric antrum. In contrast, smooth muscle tumors within the GI tract are predominantly found in the esophagus and colorectum, surpassing the incidence of GISTs in these locations. Surgical resection suffices for symptomatic benign tumors; multimodality treatment may be necessary for frank sarcomas. This article aims to elucidate the cross-sectional imaging findings associated with a wide spectrum of these tumors, providing insights that align with their histopathological features.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

A multicentre retrospective study on extra-thoracic solitary fibrous tumour: preoperative MRI findings predict intraoperative findings and postoperative prognosis

OBJECTIVE

The present study investigated the relationships between the preoperative and operative findings of solitary fibrous tumour (SFT) and between preoperative findings and prognosis.

METHODS

We reviewed 50 SFT patients treated at our musculoskeletal oncology hospital group. We analyzed preoperative clinical findings, particularly MRI imaging findings, and intraoperative information as well as the relationship between preoperative findings and outcomes.

RESULTS

Mean age was 48.9 years and the mean follow-up was 51.8 months. Prior to surgery, needle biopsy was performed on 27 patients and open biopsy on 14. T2-weighted images showed a high signal intensity in 24 patients and heterogeneous signal intensity in 20. Tumours had polylobular contours in 17 patients and smooth and round contours in 27. Collateral feeding vessels were detected in 22 patients. Gd-enhanced MRI was performed on 23 patients, and showed 15 with homogeneous enhancement and 8 with heterogeneous enhancement. Surgical times were significantly longer in patients with a retroperitoneal origin, a tumour of 10 cm or more, and polylobular-type tumours. Intraoperative blood loss was significantly greater in patients with a retroperitoneal origin and heterogeneous Gd-MRI-enhanced tumours. In histopathological evaluations, surgical margins were positive in 12 patients. Local recurrence was observed in one patient. Distant metastasis was noted in eight patients, four of whom had pulmonary metastases. Positive surgical margins were more common in polylobular-type tumours. Distant metastases were more likely to appear in patients with observable collateral feeding vessels and heterogeneous Gd-MRI enhancement.

CONCLUSION

The present results suggest that preoperative clinical findings in SFT patients predict longer surgical times and the risk of increased intraoperative blood loss. Moreover, the risk of a positive surgical margin and postoperative distant metastases may be predicted based on preoperative MRI.

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.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

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.

An extremely rare case of an isolated primary benign pelvic Solitary Fibrous Tumor in an elderly female

INTRODUCTION AND IMPORTANCE

Solitary Fibrous Tumors are highly rare spindle cell tumors of mesenchymal origin. They comprise <2 % of all types of soft tissue tumors and are characterized by an age-adjusted annual incidence rate of 0.61 per 1 million individuals for extra-meningeal Solitary Fibrous Tumors. The disease course is mostly asymptomatic but can still present with non-specific symptoms. This results in misdiagnosis and delayed treatment. In turn, morbidity and mortality rises and it will constitute a clinical and surgical burden for the affected patients.

CASE PRESENTATION

We present the case of a 67-year-old female who has a known history of controlled hypertension, who presented to our hospital complaining of non-specific pain in her right flank and lower lumbar region. Our preoperative diagnostic radiological workup demonstrated an isolated antero-sacral mass.

CLINICAL DISCUSSION

Comprehensive excision of the mass was laparoscopically achieved. Following the necessary analysis via histopathology and immunohistochemistry, we definitively established the diagnosis of an isolated primary benign Solitary Fibrous Tumor.

CONCLUSION

To the best of our knowledge, no previous cases of SFTs from our country were documented. Clinical suspicion and complete surgical resection are vital determinants in treatment of such patients. Further research and documentation are warranted to set-up the necessary guidelines for preoperative assessment, intraoperative techniques, and adequate follow-up protocols to limit the ensuing morbidity and to detect any possible neoplastic recurrence.

Mesenchymal neoplasms of the urinary bladder: a comprehensive review with focus on cross-sectional imaging findings

Mesenchymal neoplasms of the urinary bladder are exceedingly rare and display remarkable diversity. These tumors demonstrate distinct pathological features as well as variable biological behavior and cross-sectional imaging findings. The rarity of tumors, nonspecific symptoms and seemingly normal cystoscopic findings (particularly with small and exophytic tumors) frequently lead to misdiagnosis or missed diagnosis. While some tumors display characteristic cross-sectional imaging findings that may suggest a diagnosis, imaging findings are mostly nonspecific. Histopathological examination is required for accurate diagnosis, management and prognostication. The purpose of this article is to review the cross-sectional imaging findings of a diverse spectrum of mesenchymal tumors of the urinary bladder.

Resection of giant malignant solitary fibrous pleural tumor after interventional embolization: a case report and literature review

Background

Solitary fibrous tumor of the pleura (SFTP) is a rare mesenchymal tumor that arises at various sites and typically originates from the pleura. Most patients with SFTPs are asymptomatic, unless the tumor is large. Approximately 20% of SFTP cases are malignant. There are few reports on imaging diagnoses and interventional treatments of SFTP. Here, we report a case of a giant SFTP that exhibited malignant behavior and underwent successful resection after embolization of the main supply artery of the tumor.

Case presentation

We report a clinical case of a giant SFTP in a 66-year-old Chinese female patient complaining of chest tightness and cough for more than 2 months. Ten years ago, the patient had undergone a chest CT scan at a local hospital for cough. Computed tomography (CT) had revealed a mass in the right thoracic region, which was misdiagnosed as a pulmonary abscess by CT-guided biopsy. Therefore, the patient did not receive appropriate/complete treatment at that time. She was hospitalized again, because CT showed significant enlargement of the right thoracic mass, which caused her obvious symptoms of discomfort. The pathological results of CT-guided biopsy at our hospital confirmed SFTP. Considering the large size of the tumor and the rich blood supply, some of the main blood vessels were treated with embolization before surgical resection. A large tumor, about 23 cm × 16 cm × 15 cm in size, was then successfully removed by thoracic surgery. The diagnosis of malignant SFTP was confirmed by surgical pathology and immunohistochemistry.

Conclusion

Imaging findings of SFTPs are not characteristic, especially when a tumor is large, the diagnosis is difficult, and the final diagnosis still depends on histological and immunohistochemical examinations. The two-stage surgical treatment described here, which involves first embolization of the main supplying artery of the large tumor and then complete surgical resection, is effective and safe for SFTPs. Whether needle biopsy or vascular embolization is performed, intervention plays a crucial role in the diagnosis and treatment of patients with SFTPs.

Mesentery solitary fibrous tumor with postoperative recurrence and sarcomatosis: A case report and review of literature

BACKGROUND

Solitary fibrous tumors are rare neoplasms of mesenchymal origin. They are often of low malignant potential and rarely metastasize. They frequently arise from the pleura and can occur at any soft tissue site in the body. However, these tumors rarely develop in the mesentery, peritoneal cavity or peritoneum.

CASE SUMMARY

We report on a scarce case of solitary fibrous tumor of the rectal mesentery showing sarcomatosis about 4 years after previous tumor resection. This 69-year-old male had no clinical symptoms but was transferred to our hospital because of a suspected tumor recurrence from follow-up abdominal computed tomography. Tumor markers (CEA, CA 19-9 and CA 125) were within the normal range. Open laparotomy showed sarcomatosis, and pathology confirmed its mesenchymal origin and diagnosis as the solitary fibrous tumor. Our case may be the second recurrent mesentery solitary fibrous tumor reported to date, and the only one with progression to sarcomatosis. There has been no evidence of recurrence in follow-up at the 28^th mo after extensive intra-operative peritoneal lavage and cytoreductive surgery.

CONCLUSION

Although there are few risk factors of cancer recurrence in this patient, careful long-term follow-up after cytoreductive surgery is necessary.

Primary intraperitoneal solitary fibrous tumor in mesentery: How does it present?

Intra-abdominal solitary fibrous tumor (SFT), also known as hemangiopericytoma, is rare, especially for those with a mesenteric location, and only a few cases have been reported. Distinguishing a hemangiopericytoma from other intra-abdominal benign or malignant tumors can be difficult, as they have similar presentations on both computed tomography and magnetic resonance imaging. In the present study, the records for a 31-year-old Vietnamese woman who underwent abdominal surgery for greater omental tumor resection and received histopathological results revealing SFT are retrospectively reviewed. The case is discussed and similar reported cases are reviewed. Due to the aggressive behavior and high rate of postoperative recurrence associated with SFT, a thorough understanding of the radiologic and histopathological features of the disease is necessary to achieve an appropriate diagnosis and treatment.

Case Report: Two Cases of Abdominal Aggressive Fibromatosis That Mimicked Abdominal Wall Endometriosis and Review of Literature

Background: Abdominal aggressive fibromatosis (AF) can be confounded with abdominal wall endomentriosis (AWE) because they share considerable similarity. Because of the different patient prognoses and treatment strategies available, accurate pre-operative diagnosis is important. Case Presentation: We here report two cases of abdominal masses presenting as periodic changes in tumor sizes, which occurred in correlation with the menstrual cycle. The clinical findings were highly suggestive of AWE. However, the final pathological findings revealed AF. The estrogen receptor and progesterone receptor expressions were negative in the two cases. The differences between the two diseases have been discussed in detail. Conclusion: A diagnosis of AWE should be scrutinized closely if the patient does not complain of cyclic pain. Fine-needle aspiration cytology is a suitable tool for pre-operative evaluation.

Solitary fibrous tumors: Clinical and imaging features from head to toe

Solitary fibrous tumors (SFTs) are rare fibroblastic mesenchymal tumors that are usually benign with variable malignant potential. They can develop in any organ due to their spindle cell origin. The exact etiology of solitary fibrous tumors is unknown. The majority of SFTs are benign with 10-30% of them exhibiting aggressive and malignant features. The aggressiveness of this type of tumor is not associated with its histological features, which makes surgical resection the treatment of choice. We will review the clinical and radiological features and possible differential diagnoses of SFTs according to their anatomical sites following the World Health Organization 2020 classification.

[Solitary fibrous tumor of the prostate: case report]

La tumeur fibreuse solitaire est une tumeur mésenchymateuse souvent bénigne et rare décrite pour la première fois dans la plèvre, la localisation prostatique est exceptionnelle. Nous rapportons le cas d´un patient de 77 ans qui a consulté pour symptômes du bas appareil urinaire à type de dysurie et pollakiurie. Le scanner et l´imagerie par résonance magnétique (IRM) ont montré l´origine prostatique de la lésion et précisé les rapports de cette masse avec les structures adjacentes saines, élément important pour la résécabilité de la tumeur. La biopsie transrectale avec une étude immunohistochimie ont confirmés le diagnostic, les cellules tumorales exprimaient le CD34, Bcl2 et CD 99. Le traitement était chirurgical par prostatectomie radicale.

Doege-Potter syndrome: a systematic review of the literature and case presentation of a rare pelvic malignant solitary fibrous tumour

Solitary fibrous tumours (SFTs) are a rare mesenchymal neoplasm with an incidence of 2.8 per 100 000 of which only 1% occur in the female genital tract. Doege-Potter syndrome is a paraneoplastic phenomenon associated with approximately 5%-10% of SFTs and is characterised by non-islet cell hypoglycaemia due to tumour production of low molecular weight insulin-like growth factor-II. We present the fourth confirmed case of female pelvic SFT with Doege-Potter syndrome and a literature review.

A Rare Case of Solitary Fibrous Tumour of the Pelvis in an 18-Year-Old Young Man: CT and MRI Features with Pathologic Correlations

Solitary fibrous tumors (SFTs) are mesenchymal neoplasms of fibroblastic origin, even if commonly seen in the pleura, they can occur anywhere in the body. SFT presents as a slow growing, often asymptomatic mass, generally affecting middle-aged adults regardless of the sex. We report a rare case of an 18-year-old man referred to our institution to perform computed tomography (CT) and magnetic resonance imaging (MRI), to investigate a pelvic mass incidentally discovered at abdominal ultrasound examination. A well circumscribed, heterogenous and hypervascular lesion was described at imaging, with absence of calcifications, hemorrhage, necrosis nor cystic degeneration. The mass removal was performed via the Da Vinci-assisted robotic surgery. Histopathological evaluation confirmed the diagnosis of SFT. CT and MRI can aid the identification of SFT, providing useful information which needs to be supported by histopathological analysis.

Imaging spectrum of mesenteric masses

Mesenteries are extensions of the visceral and parietal peritoneum consisting of fat, vessels, nerves, and lymphatics. Mesenteric masses have a wide differential diagnosis with neoplastic, infectious, or inflammatory etiologies and can either be solid or cystic. Imaging features are critical for the diagnosis. We review the epidemiology, imaging spectrum, and differentiating features and treatment of mesenteric masses.

Giant solitary fibrous tumor of the pelvis: A case report and review of literature

INTRODUCTION

Solitary fibrous tumors (SFTs) are rare spindle cells neoplasms most likely arising from mesenchymal cells. Usually they involve the pleura. Even if extra-thoracic SFTs are rare, lately they are diagnosed with increased frequency.

CASE PRESENTATION

We describe the case of giant pelvic and retroperitoneal neoplasm, a rare solitary fibrous tumor, in a 51-year-old man that was admitted for abdominal pain.

DISCUSSION

On CT a SFT appears usually as a smooth, lobulated mass with occasional calcifications, but the imaging differential diagnosis with other mesenchymal tumors is very difficult, if not impossible.

CONCLUSION

The histological and immune-histochemical features of SFTs are helpful for the differential diagnosis. The malignant potential of this cancer is low, but it is very important to perform an optimized surgery and a close follow up in the patient. We believe that this case is particularly interesting and complex because of the difficulty of predicting the future biological behavior.

Comprehensive Review of Abdominopelvic Mesenchymal Tumors with Radiologic Pathologic Correlation and Update on Current Treatment Guidelines - Part 1

Soft-tissue sarcomas are a diverse group of rare mesenchymal malignancies accounting for only 1% of all solid adult malignancies. These have been categorized in 12 broad groups by the World Health Organization (WHO) with their recent update in 2013. Majority of them lack specific imaging features serving as imaging conundrums for a radiologist. These are often large masses at presentation as they are asymptomatic or cause vague clinical symptoms. These tumors are challenging for surgeons as well as they find it difficult to achieve complete resection because of complex intra-abdominal anatomy and their close relationship with critical structures. Often, a multidisciplinary approach is required to decide on the most appropriate management for these complex cases so as to provide optimal patient care. Knowledge of the WHO classification, pathologic features and available treatment options will help the radiologist make a meaningful contribution in multidisciplinary discussions of such cases and overall patient care. Liposarcoma (well-differentiated and dedifferentiated liposarcomas), leiomyosarcoma, and gastrointestinal stromal tumor are the 3 most common primary intra-abdominal sarcomas. In part 1 of this article, general features of soft tissue sarcomas and some of the common tumors from WHO category 1-4 found in abdomen and pelvis are discussed. Part 2 will focus on common tumors from remainder of the WHO categories.

Extra-pleural solitary fibrous tumors: a review

Solitary fibrous tumor (SFT) is a rare mesenchymal ubiquitous tumor reported in the pleura and a wide variety of extrapleural locations, most frequently in the orbits and extremities.

Approximately 78–88% of SFTs are benign and 12–22% are malignant.

Although tumor characteristics are highly dependent on the location there are unifying features in MR imaging suggesting SFT: well-circumscribed, often lobulated nodular lesion, delayed contrast enhancement and the presence of fibrous contents which are hypointense on T1 and T2-weighted MRI imaging.

There are many SFT differential diagnosis, highly dependent to the tumor location. Due to its rarity the diagnosis of extrapleural SFTs may be challenging. Histopathologic analysis is always required to confirm the diagnosis and to allow the distinction between the benign and malignant forms.

We review pleural and extrapleural SFTs, presenting diagnostic clues, differential diagnosis and prognostic factors.

Solitary fibrous tumor of the kidney: A case report

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Solitary fibrous tumor is a rare entity, representing 2% of all soft tissue tumors.

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The disease is usually described in the thoracic cavity, only 105 cases of renal solitary fibrous tumor have been reported.

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Solitary fibrous tumors are usually asymptomatic thus they are diagnosed as renal cell carcinoma and treated as such.

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Typical immunohistochemical characteristic is a high positivity for CD34.

•

As solitary fibrous tumor has a malignant potential, careful follow-up is mandatory.

Introduction

Solitary fibrous tumor (SFT) is rare, representing 2% of all soft tissue tumors and is usually described in the thoracic cavity. Only 105 cases of renal SFT have been reported.

Case presentation

A 55-year-old men with lower urinary tract symptoms, had a routine renal ultrasound which showed a cortical mass of the left kidney measuring 36 × 23 × 39 mm, with peripheral enhancement, and a central fluid collection on CT. On MRI, it was iso-intense to the kidney in T1 and hyper-intense with restricted diffusion in T2 images. The diagnosis of renal cell cancer was likely and an open partial nephrectomy was performed. Microscopic examination showed a mesenchymal neoplasm with long spindle cell and Immunohistochemical staining positive for CD34 and Bcl-2 confirming the diagnosis of SFT.

There was no evidence of tumor recurrence or metastasis nine months after discharge.

Discussion

Up to now, only 105 cases of occurring renal SFT have been reported. SFTs are usually asymptomatic when they have a small size, that’s why the diagnosis is often delayed. Blood tests do not have any diagnostic value. Imaging features are not specific for the diagnosis of SFT which are diagnosed as renal cell carcinoma and treated as such. Typical immunohistochemical characteristic is a high positivity for CD34. As SFT has a malignant potential, careful follow-up is mandatory,searching for local recurrence or metastasis which was reported in few cases.

Conlusion

SFTs are indolent tumors and are usually diagnosed as renal cell carcinomas preoperatively and the final diagnosis is always based on immunohistochemical study.

Solitary fibrous tumor/hemangiopericytoma of the penis

Solitary fibrous tumor/hemangiopericytoma (SFT-HMP) is a rare spindle-cell mesenchymal tumor, thought to be of myofibroblastic origin. Penile SFT-HMP was mentioned in the literature in two separate case reports which were published in 2015 and 2017. We present the first case of SFT-HMP which is localized on corpus cavernosum of the penis. A 55-year-old man presented to our clinic with a small and gradually growing lesion on his penis for the past year, which recently caused difficulties during sexual intercourse. On physical examination; a well-shaped, nodular non-fluctuant, solid, painless mass, measuring 4×4 cm was palpated. Magnetic resonance imaging showed 5×5 cm mass located on the right corpus cavernosa. Under spinal anesthesia, surgical excision was performed. Pathologically, the tumor had an irregular architecture patterns and was characterized by hypercellular areas separated by thin-walled, branching vessels, lined with a single layer of flattened endothelial cells. SFT-HMP rarely occurs in genital tract and penile presentation is among the rarest. It should be classified and considered under penile masses, especially if the mass is well circumscribed, painless and slowly growing in nature. After differential diagnosis, surgical excision is mandatory.

Nonepithelial Neoplasms of the Pancreas, Part 2: Malignant Tumors and Tumors of Uncertain Malignant Potential From the Radiologic Pathology Archives

Almost all neoplasms of the pancreas are derived from pancreatic epithelial components, including the most common pancreatic mass, primary pancreatic ductal adenocarcinoma (PDAC). Nonepithelial neoplasms comprise only 1%-2% of all pancreatic neoplasms. Although some may arise directly from intrapancreatic elements, many originate from mesenchymal, hematopoietic, or neural elements in the retroperitoneal peripancreatic space and grow into the pancreas. Once these tumors reach a certain size, it can be challenging to identify their origin. Because these manifest at imaging as intrapancreatic masses, awareness of the existence and characteristic features of these nonepithelial neoplasms is crucial for the practicing radiologist in differentiating these tumors from primary epithelial pancreatic tumors, an important distinction given the vastly different management and prognosis. In part 1 of this article, the authors reviewed benign nonepithelial neoplasms of the pancreas. This article focuses on malignant nonepithelial neoplasms and those of uncertain malignant potential that can be seen in the pancreas. The most common malignant or potentially malignant nonepithelial pancreatic tumors are of mesenchymal origin and include soft-tissue sarcomas, solitary fibrous tumor, and inflammatory myofibroblastic tumor. These tumors commonly manifest as large heterogeneous masses, often containing areas of necrosis and hemorrhage. The clinical features associated with these tumors and the imaging characteristics including enhancement patterns and the presence of fat or calcification help distinguish these tumors from PDAC. Hematopoietic tumors, including lymphoma and extramedullary plasmacytoma, can manifest as isolated pancreatic involvement or secondarily involve the pancreas as widespread disease. Hyperenhancing paragangliomas or hypervascular metastatic disease can mimic primary pancreatic neuroendocrine tumors or vascular anomalies.

Vaginal spindle cell epithelioma: A first complete MRI and histopathologic description

Spindle cell epithelioma of the vagina is a benign entity with fewer than sixty cases described in the literature, and only two with limited imaging findings, since the early 1950s. Early pathology literature suggested the lesions were mixed tumors of myoepithelial origin, but subsequent studies have found relatively few immunohistochemical characteristics in common with other mixed cell tumors. More recently, Mullerian, urogenital sinus epithelial, and pluripotential cell origins have been proposed. Given lesion rarity and a typical lack of imaging before excision, the imaging appearance of vaginal spindle cell epitheliomas has not been fully described in the radiology literature, and without comprehensive pathology correlation. The authors describe a case of spindle cell epithelioma in a 54-year-old woman which was incidentally discovered on MRI performed for uterine fibroid embolization planning. Pathology and immunohistochemistry confirmed the diagnosis.

Solitary fibrous tumor of the ovary

Solitary fibrous tumors commonly occur in the pleura and are rare elsewhere, especially in the female genital system. We present a case of a solitary fibrous tumor arising from the ovary in a young female in the reproductive age group. The tumor could be excised laparoscopically. We also describe the histopathological and immunohistochemical features that can help establish its diagnosis.

Soft-Tissue Sarcomas of the Abdomen and Pelvis: Radiologic-Pathologic Features, Part 2-Uncommon Sarcomas

Soft-tissue sarcomas occurring in the abdomen and pelvis are an uncommon but important group of malignancies. Recent changes to the World Health Organization classification of soft-tissue tumors include the movement of gastrointestinal stromal tumors (GISTs) into the soft-tissue tumor classification. GIST is the most common intraperitoneal sarcoma. Liposarcoma is the most common retroperitoneal sarcoma, and leiomyosarcoma is the second most common. GIST, liposarcoma, and leiomyosarcoma account for the majority of sarcomas encountered in the abdomen and pelvis and are discussed in part 1 of this article. Undifferentiated pleomorphic sarcoma (previously called malignant fibrous histiocytoma), dermatofibrosarcoma protuberans, solitary fibrous tumor, malignant peripheral nerve sheath tumor, rhabdomyosarcoma, extraskeletal chondro-osseous sarcomas, vascular sarcomas, and sarcomas of uncertain differentiation uncommonly arise in the abdomen and pelvis and the abdominal wall. Although these lesions are rare sarcomas and their imaging features overlap, familiarity with the locations where they occur and their imaging features is important so they can be diagnosed accurately. The anatomic location and clinical history are important factors in the differential diagnosis of these lesions because metastasis, more-common sarcomas, borderline fibroblastic proliferations (such as desmoid tumors), and endometriosis have imaging findings that overlap with those of these uncommon sarcomas. In this article, the clinical, pathologic, and imaging findings of uncommon soft-tissue sarcomas of the abdomen and pelvis and the abdominal wall are reviewed, with an emphasis on their differential diagnosis.

Imaging features of rare mesenychmal liver tumours: beyond haemangiomas

Tumours arising from mesenchymal tissue components such as vascular, fibrous and adipose tissue can manifest in the liver. Although histopathology is often necessary for definitive diagnosis, many of these lesions exhibit characteristic imaging features. The radiologist plays an important role in suggesting the diagnosis, which can direct appropriate immunohistochemical staining at histology. The aim of this review is to present clinical and imaging findings of a spectrum of mesenchymal liver tumours such as haemangioma, epithelioid haemangioendothelioma, lipoma, PEComa, angiosarcoma, inflammatory myofibroblastic tumour, solitary fibrous tumour, leiomyoma, leiomyosarcoma, Kaposi sarcoma, mesenchymal hamartoma, undifferentiated embryonal sarcoma, rhabdomyosarcoma and hepatic metastases. Knowledge of the characteristic features of these tumours will aid in guiding the radiologic diagnosis and appropriate patient management.

Primary Hepatic Neoplasms of Vascular Origin: Key Imaging Features and Differential Diagnoses With Radiology-Pathology Correlation

OBJECTIVE

This article describes, illustrates, and correlates imaging and pathologic features of primary vascular mesenchymal neoplasms of the liver, which arise from the vascular endothelium and perivascular epithelioid cells.

CONCLUSION

Familiarity with the spectrum of benign, malignant-potential and malignant vascular neoplasms, and nonneoplastic mimickers allows consideration in the differential diagnosis of enhancing hepatic masses. Understanding relevant pathologic features facilitates recognition of key imaging features, specifically dynamic contrast enhancement patterns on CT and MRI, which provide a useful classification system.

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.

Giant solitary fibrous tumour of the pleura an unpredictable entity: case series and literature review

A small proportion of tumours can undergo malignant transformation. We report a case series of five patients diagnosed with giant solitary fibrous tumours of the pleura. These cases highlight the unpredictable nature of this disease process, with significant variability in clinical course observed, from indolence to aggressive progression. Three patients were found to have malignant disease on explant, with two of these having preoperative imaging and histology suggesting benign pathology. This finding emphasises that accurately differentiating between benign and malignant disease on imaging and/or biopsy has low specificity and sensitivity and cannot be relied upon in guiding the management of these tumours. Patients with solitary fibrous tumours of the pleura should be managed cautiously, owing to the unpredictable and potentially aggressive clinical course. We would advocate the position that all patients with solitary fibrous tumours of the pleura should be managed as if they have malignant disease. Prolonged follow-up is required due to the risk of disease recurrence, even in patients with benign disease.

Radiological findings in pelvic solitary fibrous tumour

Solitary fibrous tumour (SFT) is an uncommon, usually benign mesenchymal neoplasm. SFT was first described in the pleura, but has subsequently been reported to occur in numerous anatomic locations including the abdomen and pelvis. Abdominopelvic SFTs are typically an indolent process, in spite of reaching a large size by the time of diagnosis. The preferred treatment is complete resection followed by extended follow-up surveillance. The risk of local recurrence and metastasis correlates with tumour size and the histological status of surgical margins. We present the imaging findings of a large pelvic SFT in a 61-year-old female, including ultrasound, CT and MRI.

Solitary Fibrous Tumor of the Kidney: A Case Report and Literature Review

Solitary fibrous tumors are neoplasms of mesenchymal origin that may occur virtually in any body part, most commonly arising from the pleura. Solitary fibrous tumor of the kidney is exceptionally rare, and limited clinical knowledge regarding its behavior makes prognosis of the neoplasm difficult. We report a case of solitary fibrous tumor of the left kidney and describe its clinical, imaging, and pathological features.

Imaging of presacral masses--a multidisciplinary approach

Our objective is to describe an approach for retrorectal/presacral mass evaluation on imaging with attention to imaging features, allowing for refinement of the differential diagnosis of these masses. Elaborate on clinically relevant features that may affect biopsy or surgical approach, of which the radiologist should be aware. A review of current literature regarding the diagnosis and treatment of retrorectal/presacral masses was performed with attention to specific findings, which may lend refinement to the differential diagnosis of these masses. Cases were obtained by searching through a radiology database at a single institution after Institutional Review Board approval. Recent advances in imaging and treatment methods have led to the increased role of radiology in both imaging and tissue diagnosis of retrorectal masses. Surgical philosophies surrounding the treatment of these masses have not significantly changed in recent years, but there are a few key factors of which the radiologist must be aware. The radiologist can offer refinement of the differential diagnosis of retrorectal masses and can elaborate on salient findings which could alter the need for neoadjuvant chemoradiation therapy, pre-surgical tissue diagnosis and surgical approach. This article presents an imaging approach to retrorectal/presacral masses with emphasis on findings which can dictate the ultimate need for neoadjuvant therapy and pre-surgical tissue diagnosis and alter the preferred surgical approach. This article consolidates key findings, so radiologists can become more clinically relevant in the evaluation of these masses.

Imaging findings of solitary fibrous tumor in the abdomen and pelvis

PURPOSE

The purpose of this study was to investigate the imaging characteristics of solitary fibrous tumor (SFT) in the abdomen and pelvis.

METHODS

Nine cases of SFT confirmed by surgery and pathology were retrospectively analyzed in terms of computed tomography (CT, eight cases) and magnetic resonance imaging (MRI, one case).

RESULTS

SFT were located in the retroperitoneum (4/9), abdominal cavity (1/9), pelvis (4/9). Eight cases were single (8/9) and one case (1/9) with three tumors. The average tumor size of 11 lesions was 9.7 cm (4.7-20 cm). Nine tumors were round or ovoid, and two lesions were irregular. The CT value of the plain scans ranged from 33 to 43 Hounsfield units (HU, mean 37.6 HU) in five cases. Arterial-phase CT found solid parts demonstrate avid enhancement (eight cases) and five of them presented with multiple circuitous vessels along the periphery with a CT value of 68-89 HU (mean 76.6 HU). In the venous and delayed phases, enhancement was strengthened progressively. The CT values at venous (eight cases) and delayed phases (five cases) were 108-115 and 112-123 HU respectively, with averages of 109.8 and 114.8 HU. Patch or nodular no-enhanced areas were observed in eight cases during the enhanced phases. One case showed isointensity on T1-weighted images and high signal intensity on T2-weighted images accompanied by linear or curvilinear hypointense lines. Intense enhancements along with linear no-enhancement areas are seen in the arterial and venous phases.

CONCLUSION

The possibility of SFT should be considered when a single or multiple masses with sharp border, inhomogeneous density or signal are detected, especially, with inhomogeneous intense enhancement in the arterial phase being maintained in the venous and delayed phases.

Massive malignant solitary fibrous tumor arising from the bladder serosa: a case report

Introduction

Solitary fibrous tumors are rare neoplasms of mesenchymal origin. They are often of low malignant potential and rarely metastasize. While they frequently arise from the pleura, they can occur at any soft tissue site in the body. We present a case of a large (28 × 21cm) malignant solitary fibrous tumor arising from the bladder serosa. In addition, the clinicopathologic features, differential diagnosis, cytogenetics and management of this rare disease are discussed, along with a review of the existing literature on this topic.

Case presentation

An otherwise healthy 41-year-old Caucasian man presented with weight loss and progressive abdominal bloating. A subsequent computed tomography scan of his chest, abdomen and pelvis revealed a 26.8 × 21cm intra-abdominal mass occupying most of his abdominal cavity. The inferior vena cava was compressed, and the mass extended inferiorly to his upper pelvis abutting the superior dome of his bladder. He underwent operative resection and the resected mass measured 28 × 21 × 18cm and weighed 4.8kg. The cut surface revealed a gray-white mass with an ill-defined whorled-like pattern, with randomly assorted tan fleshy nodules. A histologic evaluation revealed variable, alternating hypercellular and hypocellular areas, with areas of necrosis. The tumor cells varied from spindle to epithelioid within a hyalinized stroma. In the hypercellular areas, the tumor cells showed moderate atypia with high mitotic activity. The histological features combined with immunophenotyping were suggestive of a malignant solitary fibrous tumor that grossly appeared to be growing from the bladder serosa, specifically the intraperitoneal superior dome of the bladder. Our patient is currently eight months post-surgery without evidence of recurrence.

Conclusions

Extrapleural occurrences of solitary fibrosis tumors are being increasingly observed. Malignant solitary fibrosis tumors of the urinary bladder, however, are very rare. As there are no pathognomonic features of malignancy, surgical resection is often both diagnostic and therapeutic, as was the case in our report.

Solitary fibrous tumors in abdomen and pelvis: Imaging characteristics and radiologic-pathologic correlation

AIM: To describe the imaging features of solitary fibrous tumors (SFTs) in the abdomen and pelvis, and the clinical and pathologic correlations.

METHODS: Fifteen patients with pathologically confirmed SFTs in the abdomen and pelvis were retrospectively studied with imaging techniques by two radiologists in consensus. Patients underwent unenhanced and contrast-enhanced imaging, as follows: 3 with computed tomography (CT) and magnetic resonance imaging (MRI) examination, 8 with CT examination only, and 4 with MRI examination only. Image characteristics such as size, shape, margin, attenuation or intensity, and pattern of enhancement were analyzed and correlated with the microscopic findings identified from surgical specimens. In addition, patient demographics, presentation, and outcomes were recorded.

RESULTS: Of the 15 patients evaluated, local symptoms related to the mass were found in 11 cases at admission. The size of the mass ranged from 3.4 to 25.1 cm (mean, 11.5 cm). Nine cases were round or oval, 6 were lobulated, and 10 displaced adjacent organs. Unenhanced CT revealed a heterogeneous isodense mass in 7 cases, homogeneous isodense mass in 3 cases, and punctuated calcification in one case. On MRI, most of the lesions (6/7) were heterogeneous isointense and heterogeneous hyperintense on T1-weighted images and T2-weighted images, respectively. All tumors showed moderate to marked enhancement. Heterogeneous enhancement was revealed in 11 lesions, and 7 of these had cysts, necrosis, or hemorrhage. Early nonuniform enhancement with a radial area that proved to be a fibrous component was observed in 4 lesions, which showed progressive enhancement in the venous and delayed phase. No statistical difference in the imaging findings was observed between the histologically benign and malignant lesions. Three patients had local recurrence or metastasis at follow-up.

CONCLUSION: Abdominal and pelvic SFTs commonly appeared as large, solid, well-defined, hypervascular masses with variable degrees of necrosis or cystic change that often displaced adjacent structures.