From the archives of the AFIP: benign fibrous tumors and tumorlike lesions of the mesentery: radiologic-pathologic correlation

Retroduodenal lymphangiomyoma: A rare cause of abdominal pain - A case report

BACKGROUND

Lymphangiomyomas are rare benign tumors arising from the lymphatic system, most commonly found in the retroperitoneum. Retroduodenal lymphangiomyomas are exceedingly rare and present significant diagnostic challenges due to their nonspecific symptoms and overlapping features with other retroperitoneal and gastrointestinal pathologies.

CASE PRESENTATION

We report a 48-year-old man with persistent abdominal pain lasting several weeks. Clinical examination and laboratory investigations were unremarkable. Gastroscopy revealed no abnormalities. Contrast-enhanced computed tomography (CT) identified a well-demarcated, non-enhancing retroduodenal soft tissue lesion measuring 36 mm × 30 mm with punctate calcifications, suggestive of a benign process. Endosonography confirmed the lesion's location between the aorta and inferior vena cava. A fine-needle biopsy was avoided due to the lesion's vascular nature. Surgical excision was performed, and histopathological analysis revealed anastomosing vascular channels with smooth muscle proliferation, confirming the diagnosis of lymphangiomyoma. Postoperative recovery was uneventful, and follow-up imaging showed no recurrence.

DISCUSSION

This case underscores the importance of a multidisciplinary approach involving radiology, surgery, and pathology in the diagnosis and management of retroduodenal lymphangiomyomas. Contrast-enhanced CT and histopathology are critical in distinguishing lymphangiomyomas from other retroperitoneal masses. Complete surgical excision remains the definitive treatment to prevent recurrence.

CONCLUSION

Although rare, retroduodenal lymphangiomyomas should be considered in the differential diagnosis of retroperitoneal masses with nonspecific symptoms.

Mesenteric desmoid tumor in its cystic form: Case report of a very rare variant

Desmoid tumors, also known as deep fibromatosis or desmoid-type fibromatosis, represent a rare subset of deep fibromatoses. It is a locally aggressive tumor, with no specific symptoms, and no metastatic potential. We report a case of a 38-year-old male patient with an abdominal mass. Radiological findings showed 2 tumors, the first was a solid inguinal mass of the left lateral iliac pedicle, and the second was a giant cystic mass in the abdominal cavity. An elective explorative laparotomy was performed to remove the 2 masses. Histopathological examination confirmed the desmoid tumor diagnosis of both lesions.

Mesenteric inflammatory pseudotumor: A rare case report and review of the literature

Inflammatory pseudotumor (IP) is a rare type of benign tumor. Although initially identified in the lung, it has now been identified in a number of somatic and visceral sites, but mesenteric presentation is uncommon and has a variable clinical presentation. As inflammatory pseudotumor mimic malignancy both clinically and radiologically, the radiologist should be familiar with this entity. The only effective treatment is complete surgical resection. We present the case of a 55-year-old woman who presented with chronic abdominal pain and was diagnosed with a mesenteric inflammatory pseudotumor, in an attempt to illustrate the different imaging aspects of this benign condition in ultrasound, computed tomography and magnetic resonance imaging, and to simplify the description of these tumors.

Primary and secondary tumors of the peritoneum: key imaging features and differential diagnosis with surgical and pathological correlation

Peritoneal malignancies represent a diagnostic challenge for abdominal radiologists, oncologists, surgeons and pathologists in multidisciplinary teams, who must address their differential diagnosis, staging and treatment. In this article, we explain the pathophysiology of these processes and lay out the role of different imaging techniques in their evaluation. Then, we review the clinical and epidemiological aspects, the main radiological features and the therapeutic approaches for each primary and secondary peritoneal neoplasm, with surgical and pathological correlation. We further describe other rare peritoneal tumors of uncertain origin and a variety of entities that may mimic peritoneal malignancy. Finally, we summarize the key imaging findings of each peritoneal neoplasm to facilitate an accurate differential diagnosis that may impact patient management.Clinical relevance statementImaging plays an essential role in the evaluation of peritoneal malignancies, assessing their extension, detecting unfavorable sites of involvement and facilitating an accurate differential diagnosis, helping to choose the best therapeutic approach.

Laparoscopic excision of inflammatory pseudotumors: A case report

Inflammatory pseudotumors (IPs) are rare incidental benign lesions which can occur in any anatomical site. They have been reported by a variety of names, including inflammatory myofibroblastic tumor, histiocytoma, xanthoma, and plasma cell granuloma. Their knowledge is important because of the differential diagnosis with others true malignancies. Only 30 case reports are reported in the literature. Surgical resection is the mainstay of treatment with excellent outcomes and low recurrence rates. When anatomical site is suitable, a laparoscopic approach should be performed to minimize morbidity and expedite recovery. Here, we present a case report of IPs of antimesenteric bowel treated with a laparoscopic surgical approach.

Gas-containing mesenteric desmoid-type fibromatosis: A case report

RATIONALE

Desmoid-type fibromatosis is a rare benign mesenchymal neoplasm. Only 8% of desmoid-type fibromatosis develops in the abdominal cavity. The mesentery is seldom affected and gastrointestinal stromal tumors need to be considered in the differential diagnosis, particularly when imaging examination shows a tumor containing gases in the abdominal cavity. Only a few cases of gas-containing mesenteric desmoid-type fibromatosis have been reported in the literature.

PATIENT CONCERNS

A 69-year-old male patient presented with hematochezia and intermittent upper abdominal pain.

DIAGNOSIS

Contrast-enhanced computed tomography revealed a 3.9 × 3.6 cm gas-containing mass infiltrating the third portion of the duodenum. The tumor was heterogeneous, with cysts and air bubbles. It showed heterogeneous weak-to-mild enhancement in the solid part. Postoperative pathological examination confirmed a final diagnosis of mesenteric desmoid-type fibromatosis.

INTERVENTIONS

The patient underwent surgical resection of intra-abdominal lesion.

OUTCOMES

No evidence of local recurrence was noted during the 6 months of follow-up.

LESSONS

Accurate preoperative diagnosis is difficult for an intra-abdominal gas-containing mass on computed tomography scan. The appearance of spiculated infiltrative margin suggests the diagnosis of desmoid-type fibromatosis. Further investigation of imaging evidence and treatment methods is necessary.

Magnetic resonance imaging features of a solitary fibrous tumor of the vulva: a case report

Solitary fibrous tumors (SFTs) are commonly seen in the pleura. SFT involvement of the vulva is rare, and clinical diagnosis is mainly based on histopathological and immunohistochemical analyses. We herein describe the imaging features of a 69-year-old woman with an SFT of the vulva. The SFT was hypointense on T1-weighted images, similar to muscle; however, it showed inhomogeneous hyperintensity predominantly on fat-suppressed T2-weighted images. An area of low signal intensity was evident on T2-weighted images, and the tumor showed progressive enhancement in delayed phases. The tumor also displayed heterogeneous and prolonged, persistent enhancement, and serpentine vessels were present in the peritumoral area as signal voids. Pathological examination confirmed that the lesion was an atypical SFT originating from the vulva, and it was composed of spindle cells and perivascular and stromal hyalinization. This case reveals the characteristic imaging findings of vulvar SFT and their association with the relevant pathological findings, thus contributing to the primary diagnosis and preoperative evaluation of this potentially aggressive tumor.

Peritoneal disease: key imaging findings that help in the differential diagnosis

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant condition to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review, we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis.We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

Intra-abdominal Desmoid-Type Fibromatosis Mimicking Diverticulitis With Abscess: A Case Report

BACKGROUND

Intra-abdominal desmoid-type fibromatosis (DF) rarely necessitates emergency surgery. However, the condition is difficult to diagnose preoperatively and can become life-threatening if left untreated.

CASE REPORT

A 46-year-old man complained of fever and right lower quadrant pain. In computed tomography, the mesenteric side of the ascending colon demonstrated air and fluid collections, suggesting diverticulitis with abscess. After 2 weeks of conservative treatment with fasting, the patient started to consume food; nonetheless, fever returned. Colonoscopy and contrast enema detected a fistula extending from the ascending colon to the abscess, with no surrounding lesions. Surgery was then performed because the abscess was refractory. During laparotomy, the scar tissue of the abscess was found to be attached to the lateral wall of the ascending colon. Hence, right colectomy combined with abscess resection was performed. Histopathological findings revealed DF in the mesentery.

CONCLUSION

Although rare, DF should be included in the preoperative differential diagnosis of intra-abdominal abscesses.

Magnetic Resonance Imaging, the Virtual Biopsy of Mesenteric Masses

ABSTRACT

The mesentery may be affected by multiple disease processes. Magnetic resonance imaging aids as a virtual pathological biopsy tool in the assessment of mesenteric masses because of superior soft tissue contrast and characterization. In this comprehensive review, we describe in detail the magnetic resonance imaging features of some solid and cystic mesenteric masses, with an emphasis on lesion-specific signal characteristics on T1- and T2-weighted images, diffusion-weighted imaging, and enhancement features on the dynamic postcontrast phase that aid in narrowing the differential diagnosis.

[Imaging of Mesentery and Omentum]

Although primary tumors in the mesentery and omentum are relatively rare, it is often necessary to distinguish them from other non-tumorous diseases. Since the omentum and mesentery are major routes for the spread of various abdominal diseases, the anatomy, type, and pattern of the diseases affecting these organs should be known in detail for accurate differential diagnosis. In addition, it is important to detect and promptly treat hidden lesions in the mesentery and omentum. Therefore, careful observation of the area where the lesion occur should be emphasized when assessing mesentery and omentum in abdominal CT.

Left-sided omental infarction without torsion: report of a case with radiologic-pathologic correlation

Background

Omental infarction is a rare disease that affects the entire omentum or a segment of the greater omentum. It presents as acute abdominal pain mainly in the right lower quadrant or right flank. Left-sided omental torsion is infrequent and it is rarely preoperatively diagnosed.

Omental infarction is a differential diagnosis in the acute abdomen. As most cases of omental infarction can be adequately diagnosed via computed tomography, a conservative treatment strategy for patients without complications should be considered in order to avoid any unnecessary surgical intervention.

Case presentation

We herein report a case of a surgically proved left-sided infarction of the greater omentum presenting with abdominal pain, tenderness of the left flank. Specifically, we describe the ultrasound (US) and computed tomography (CT) findings of this rare disease providing a radiological-pathological correlation of them. To date, there are few similar correlation reports in literature.

Conclusions

Although the classical treatment of omental infarction is surgery, more recently the conservative management has been suggested. Thus, we believe that the knowledge of the characteristic imaging findings is essential for establish a correct preoperative diagnosis, which can avoid unnecessary surgical intervention.

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.

Unravelling the Mysteries of the Mesentery

The mesentery and its folds tether the small bowel loops to the posterior abdominal wall. It transmits nerves, vessels, and lymph ensconced in a fatty sponge layer wrapped in a thin glistening peritoneum, from and to the small bowel. Not only does this flexible dynamic fatty apron house various localized primary benign and malignant lesions, it is often involved in and gives an indication of generalized or systemic diseases in the body. An understanding of the anatomy, components, and function of the mesentery helps to classify mesenteric abnormalities. This further allows for characterizing radiological patterns and appearances specific to certain disease entities. Recent reviews of mesenteric anatomy have kindled new interest in its function and clinical applications, heralding the possibility of revision of its role in diseases of the abdomen.

The Peritoneum: What Nuclear Radiologists Need to Know

The peritoneum is the largest and most complex serous membrane in the human body. The peritoneal membrane is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum is one continuous sheet, forming two layers and a potential space between them - the peritoneal cavity- which is subdivided into multiple communicating spaces containing small amount of serous fluid that facilitates frictionless movement of mobile intraabdominal viscera. Peritoneum also contributes to fluid exchange mechanism and plays a role in immune response. The peritoneum is subject to many neoplastic and non-neoplastic processes including infections, trauma, developmental and inflammatory processes. Different Nuclear Medicine imaging techniques can be used to diagnose peritoneal diseases, most of these techniques can be customized depending on the clinical scenario and expected findings. Peritoneal scintigraphy can detect abnormal peritoneal communication or compartmentalization. Several nuclear medicine techniques can help characterize intraperitoneal fluid collections and differentiate sterile from infected fluid. PET imaging plays an important role in imaging of different neoplastic and non-neoplastic peritoneal pathologies. Nuclear radiologists need to be familiar with peritoneal anatomy and pathology to interpret peritoneal findings in dedicated peritoneal nuclear medicine imaging studies, as part of more general nuclear medicine scans, or on CT or MRI component of hybrid imaging studies. The purpose of this article is to review the normal peritoneal anatomy, various pathologic processes involving the peritoneum, and different nuclear medicine and hybrid imaging techniques that can help detect, characterize, and follow up peritoneal pathology.

Non-neoplastic conditions mimicking peritoneal carcinomatosis at CT imaging

The general appearance of peritoneal carcinomatosis at abdominal CT and other cross-sectional imaging modalities consists of varying amounts of peritoneal-based soft tissue implants (mass-forming or infiltrative), peritoneal fluid, and occasionally calcification. However, a wide variety of common and uncommon neoplastic and non-neoplastic conditions can closely mimic peritoneal carcinomatosis at imaging. Neoplastic mimics of peritoneal carcinomatosis include primary peritoneal and sub peritoneal tumors, as well as peritoneal lymphomatosis and sarcomatosis.Broad categories of non-neoplastic mimics of peritoneal carcinomatosis include tumor-like conditions, systemic processes, atypical infections, and fat-based conditions. For many entities, suggestive or specific patient information and/or CT imaging findings exist that may allow the radiologist to narrow the differential diagnosis. In this article, we review the salient clinical and cross-sectional imaging features of non-neoplastic mimics of peritoneal carcinomatosis and malignancy, with emphasis on the CT findings and the additional clues that may suggest the correct benign diagnosis.

Soft Tissue Tumors of the Abdomen and Retroperitoneum

Soft tissue tumors of the abdomen and retroperitoneum encompass a wide range of benign and malignant neoplasms. Retroperitoneal sarcomas, the most common, are composed of rare malignancies with numerous histiotypes. Surgery remains the cornerstone of treatment and the only curative option for retroperitoneal sarcomas. With histiotype-dependent local and distant recurrences, it is imperative these cases are discussed in a multidisciplinary tumor board setting at specialized sarcoma centers. This review discusses the current evidence for the management of abdominal and retroperitoneal soft tissue tumors, with particular focus on retroperitoneal sarcomas and desmoid tumors.

Non-adrenal tumors of the adrenal area; what are the pitfalls?

Discovery of an adrenal mass is nowadays a frequent situation. While adrenal tumors can cause a variety of symptoms, more often than not they are diagnosed incidentally on imaging exams such as CT-scan or MRI performed for another purpose. However, any retroperitoneal supra-renal mass can have an extra-adrenal origin. Indeed, operated non-adrenal masses initially but wrongly diagnosed as an adrenal disease represent about 3.5% of adrenalectomies. These differential diagnoses principally include retroperitoneal tumors that are malignant in two thirds of cases (lymphomas, sarcomas, neurogenic or germinal tumors), and more rarely vascular anomalies or congenital malformations, which are most frequently left-sided due to the wide variety of anatomical structures surrounding the left adrenal gland. Several lesions can originate from the adrenal gland or be located near the gland (paraganglioma, ganglioneuroma). Even though unilateral adrenalectomy is associated with low morbidity, ignorance of these differential diagnoses can cause ill-adapted management; overly conservative surgery in case of sarcoma is one example. Some of these lesions have characteristic clinical or imaging features (cystic lymphangioma, angiomyolipoma…). In other cases, assessment of hormonal secretion is required and additional exams (MRI, percutaneous biopsy, PET-scan with 18-Fluorodeoxyglucose) can correct an erroneous diagnosis. The above diagnostic approach allows appropriate management (with or without surgery). The purpose of this review was to highlight the main differential diagnoses of adrenal masses, to describe their characteristics, and to discuss their therapeutic management.

Overlooked and Challenging Encounters–Inflammatory Pseudotumors in the Abdomen and Pelvis: A Pictorial Essay

Inflammatory pseudotumors (IPTs) are uncommon, mass-forming lesions, predominantly involving the lung and orbit. Although the incidence of IPTs is rare in the abdomen and pelvis, they can be encountered as enhancing, soft-tissue lesions, mimicking malignancy or fibrosclerosing disease. Generally, they exhibit a wide range of nonspecific imaging features in various organs. Preoperative imaging diagnosis of IPTs in appropriate clinical settings may help determine proper patient management. In this article, we review radiologic findings of IPTs in the abdominopelvic cavity, including the liver, spleen, kidney, gastrointestinal tract, mesentery, pelvis, and retroperitoneum.

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.

Demystifying the mesenteric root lesions

OBJECTIVE

The aim of this article is to describe the normal anatomy of the root of the small bowel mesentery (RSBM) as well as the multidetector computed tomography (MDCT) features of the various primary and secondary lesions that affect the RSBM.

RESULTS

The small bowel mesentery attaches the jejunum and ileum to the posterior abdominal wall, the line of attachment forming the RSBM. Several primary as well as secondary lesions involve the RSBM. The RSBM has anatomical contiguity with the mesocolon and other peritoneal ligaments, which forms a route for the spread of infection, neoplasms as well as several other abdominal pathologies. MDCT plays an important role in the evaluation of mesenteric root lesions.

CONCLUSION

Familiarity with the lesions involving the RSBM and their characteristic appearances on MDCT is important in giving thoughtful differential diagnosis and guiding the treating physician in further management.

Sclerosing Mesenteritis

Sclerosing mesenteritis is a rare non-neoplastic disorder characterized by fat necrosis, chronic inflammation, and fibrosis typically of the small bowel mesentery. Our understanding of this disorder is limited by its rarity as well as inconsistent terminology used across the literature. While prior abdominal surgery or trauma, autoimmunity, infection, ischemia, and malignancy have been suggested to be involved in the pathogenesis of the disorder, it remains poorly understood. The clinical course of sclerosing mesenteritis is generally benign with a large proportion of patients diagnosed incidentally on imaging obtained for other indications. In a subset of patients, symptoms may arise from a mass effect on the bowel, lymphatics, or vasculature resulting in bowel obstruction, chylous ascites, or mesenteric ischemia. Symptomatic patients should be treated with a combination of corticosteroid and tamoxifen as first-line therapy based on retrospective case series and experience in other fibrosing disorders. Surgical intervention may be required in those with persistent obstruction despite conservative treatment, though complete resection of the mass is often not feasible given intimate involvement with the mesenteric vasculature. A careful use of terminology and communication between the radiologist, pathologist, and clinicians in the care of these patients will be essential to future efforts at understanding this disease.

Mesenteric Tuberculosis Masquerading as Carcinoid Tumor on Conventional Imaging and DOTANOC Positron Emission Tomography/Computed Tomography: Uncommon Presentation of a Common Disease

Carcinoid tumor of the mesentery has a classical imaging morphology. A specific diagnosis can often be provided on the basis of clinical history, elevated serum neuroendocrine markers, and uptake on somatostatin receptor-based radiotracer studies. Although a number of inflammatory and neoplastic conditions may mimic carcinoid tumor on many of these modalities, uptake on ⁶⁸Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) is considered specific. We report a case of a 28-year-old male presenting with a mesenteric mass along with elevated serum neuroendocrine markers and uptake on DOTANOC PET/CT, all suggestive of carcinoid tumor. However, the histopathologic examination after surgical resection revealed necrotizing granulomas consistent with tuberculosis (TB). This case highlights the great masquerader that TB can be and stresses the importance of keeping a high index of suspicion for TB, especially in endemic areas.

Mesenteric panniculitis: comparison of computed tomography findings in patients with and without malignancy

Purpose

The aim was to compare computed tomography (CT) findings between patients with mesenteric panniculitis (MP) with and without known malignancy.

Patients and methods

We retrospectively analyzed 116 consecutive patients who were diagnosed with MP on the basis of CT findings and categorized them according to the absence (Group 1: 73 patients) or presence (Group 2: 43 patients) of malignancy. Patient age and sex, diameter, size, mass effect, location, and fat density of the MP mass, presence of a pseudocapsule and/or halo sign, and lymph node status were compared between the two groups.

Results

MP tends to be more common in males, and this trend shows statistical significance when combining the findings for both groups (P=0.041). Patients in Group 1 were significantly younger than those in Group 2 (54.29 vs 64.77 years, P=0.001). A well-defined fatty mass at the small bowel root was observed in all patients. The halo sign was present in most cases in both groups. A pseudocapsule was observed in 36 patients (49%) in Group 1 and 29 (67%) in Group 2 (P=0.045). The average craniocaudal diameter of the MP masses on the sagittal view was 11.14 and 12.5 cm in Groups 1 and 2, respectively (P=0.005). The MP fat density was less negative in patients with malignancy (–66 vs –76 HU, P=0.001). Lymph node status was similar in both groups.

Conclusion

Detailed CT features should be evaluated in patients with MP, as some of these features may indicate an associated malignancy, necessitating further investigation and close follow-up.

Desmoid-type fibromatosis mimicking cystic retroperitoneal mass: case report and literature review

Background

Retroperitoneal desmoid-type fibromatosis (DF) is an uncommon mesenchymal neoplasm presenting as a firm mass with locally aggressive features. It usually manifests as a well-circumscribed or ill-defined, solid mass on cross-sectional imaging. Cystic changes of DF have been described in the literature in association with prolonged medical treatment or abscess formation. However, spontaneous cystic change is rarely reported.

Case presentation

Here we report the case of a 46-year-old patient with a DF mimicked a large cystic tumor in the retroperitoneum. Ultrasonography and computed tomography were performed in order to search for localizations and characteristics of the cystic tumor. Radiological findings showed an oval cystic mass with a relatively thick wall, measuring 18.3 × 12.3 × 21.5 cm in the left upper abdomen. Laparoscopic spleen-preserving distal pancreatectomy was performed and histopathological examination by immunohistochemical study enabled us to diagnose a DF invading the pancreatic parenchyma. The patient remained asymptomatic during an 8-month follow up period.

Conclusions

We report an extremely rare case of retroperitoneal DF with spontaneous cystic change. DF can manifest as a mainly cystic mass with a thick wall, as in our case, which makes the correct diagnosis difficult. DF should be included in the preoperative differential diagnosis of a cystic retroperitoneal mass, regardless of its rarity.

Solitary Fibrous Tumor of Small Bowel Mesentery: A Case Report and Review of the Literature

Solitary fibrous tumor is an extremely rare clinical entity, most commonly manifested in the pleura and peritoneum. An increasing number of cases are found to occur at extrapleural sites. We report a case of solitary fibrous tumor arising from the mesentery of the small intestine. A 53-year-old man presented with a large abdominal mass which was initially thought to be a gastrointestinal stromal tumor. The tumor was successfully removed surgically and the diagnosis of solitary fibrous tumor was confirmed on immunohistochemical analysis. To our knowledge this is the first reported case of a solitary fibrous tumor arising from the small bowel mesentery. Free full text available at www.tumorionline.it

Computed Tomography and Magnetic Resonance Imaging Findings of Inflammatory Pseudotumors in the Abdomen and Pelvis: Current Concepts and Pictorial Review

The group of inflammatory pseudotumors (IPTs) encompasses a variety of rare neoplastic and nonneoplastic entities described to occur in almost every location in the body and whose clinical features and aggressive imaging findings (varying from infiltrative to mass-forming lesions), frequently mimic those of malignant tumors. The radiologic features of IPTs are variable and nonspecific, the imaging findings depending on the body location and involved organ. Abdominopelvic IPTs are rare and the purposes of this review, therefore, are to familiarize the radiologist with the wide spectrum of computed tomography and magnetic resonance imaging findings of IPTs in various locations throughout the abdomen and pelvis, discussing the imaging features that allow consideration of IPTs in the differential diagnosis of soft-tissue masses within the pertinent clinical setting. Radiologists should be aware of this group of entities, as a preoperative histopathologic diagnosis upon radiological suspicion may help to differentiate IPTs from malignancy and to allow the most appropriate clinical work-up for these patients.

Omental fibromatosis treated by laparoscopic wide surgical resection

The current report presents a case of an omental fibromatosis discovered incidentally in a 46-year-old woman with no particular medical history and few symptoms. A surgical biopsy was performed initially, and microscopic examination revealed myofibroblastic proliferation. After additional immunohistochemical and molecular analyses, omental fibromatosis was diagnosed. Omental fibromatosis, also called intra-abdominal desmoid, is a rare and benign tumour but can be locally aggressive. Majority of cases are asymptomatic, and difficult to diagnose based on clinical presentation and radiological investigation. Final diagnosis is usually made on histopathology and immunohistochemistry studies. Surgical wide excision is currently the treatment of choice.

[Benign mesenchymal tumors of the abdomen]

BACKGROUND

Benign mesenchymal tumors of the abdomen are-except for hemangiomas-rare neoplasms that are associated with potentially life-threatening complications. Thus, awareness of the most important entities and knowledge of their imaging characteristics is fundamental for the radiologist.

OBJECTIVES

An overview of the most frequent benign abdominal soft tissue tumors and their common imaging features is given. Furthermore, other facts concerning the individual entities that are relevant to radiologic practice are outlined.

MATERIALS AND METHODS

A literature search and evaluation of the institutional image database were performed.

RESULTS

Hemangiomas, desmoid tumors, lipomas and lipoma variants are presented. Typical characteristics and radiological signs (e. g., iris diaphragm sign, band sign, India ink artifact) are elucidated and illustrated by image examples.

CONCLUSION

Despite the lack of distinctive imaging features, there are a few radiological characteristics suggestive for each of the entities that in many cases allow for correct diagnosis. In cases of doubt, biopsy or surgery is necessary to distinguish them from malignancies.

Solitary fibrous tumour of the mesentery: a case report

We present the case of a male with an asymptomatic abdominal mass, where imaging-guided biopsy confirmed the lesion as a solitary fibrous tumour arising from the mesentery. This is a notably rare location for solitary fibrous tumours with only a few reported cases in the literature.

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.

Effective treatment of aggressive fibromatosis with celecoxib guided by genetic testing

Aggressive fibromatosis (AF) or desmoid tumors is an aggressive fibroblastic proliferation which is locally invasive but can not metastasize. The treatment of AF is challenging. Surgery was the main treatment modality for AF in the past, other strategies including radiotherapy, systemic therapies and wait-and-see policy. The use of non-steroidal anti-inflammatory drugs (NSAIDs) and targeted therapies has demonstrated good results. In the case report, a 39-year-old man presented with progressive chest wall pain. Computed tomography (CT) showed an approximately 46× 13 mm soft-tissue mass between the inside of the fifth and sixth rib on the right side. The entire mass was excised and an AF was confirmed based on histopathology. Four months after surgery, magnetic resonance imaging (MRI) showed a soft-tissue mass in surgical areas and biopsy confirmed local recurrence. Therefore, Tomotherapy was administered. However, two months later, an (18)F-fluorodeoxyglucose (FDG) Positron Emission Tomography combined with CT (PET-CT) revealed the presence of an FDG-avid mass in the area of local recurrence. Genetic testing reported the presence of a p.T41A mutations on the CTNNB1 gene, which predicted that he is sensitive to the COX-2 inhibitor celecoxib. The tumor regressed rapidly after the application of celecoxib. Within the 20-month follow-up period, the patient showed remarkable regression without any signs and symptoms. Our case report provides further evidence for the efficacy of celecoxib in AF with CTNNB1 gene mutations. To our knowledge, this is the first report of AF treated with celecoxib under the guidance of the genetic testing. However, further studies are required.

Duodenum-derived fibromatosis that invaded the muscular layer of intestinal wall: A rare case report

RATIONALE

Intraabdominal fibromatosis is a rare benign tumor that often affects the mesentery or retroperitoneum, and can infiltrate adjacent organs. However, it is rare for fibromatosis to arise from the small intestinal wall.

PATIENT CONCERNS

A 27-year-old female with a tangible abdominal tumor is described.

DIAGNOSES

The computed tomography (CT) scan revealed a 7.5 cm, small intestine-associated tumor in the right abdomen.

INTERVENTIONS

The patient received tumor resection and intestinal anastomosis.

OUTCOMES

Further pathological examination confirmed the tumor as a duodenal fibromatosis that infiltrated the intestinal wall. To the best of our knowledge, this is the first report of a duodenum-derived fibromatosis that invaded the muscular layer of the intestine.

LESSONS

Our study demonstrated that an unexplained abdominal mass should be noteworthy and properly treated.

Imaging of the pediatric peritoneum, mesentery and omentum

The normal peritoneal structures, including the mesenteries and the omenta, are only a few cell layers thick and are visible on imaging based upon the tissues (e.g., fat) and structures (e.g., blood vessels and lymph nodes) contained within them. These structures become more visible and change in appearance when involved by pathological processes. In this pictorial essay, we discuss the normal anatomy of the various abdominopelvic peritoneal structures and illustrate numerous developmental and acquired diagnoses that involve these structures in the pediatric and young adult population.

Inflammatory myofibroblastic tumor of the lumbar spinal canal: A Case Report With Literature Review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare type of mesenchymal tumor. IMT can arise in multiple anatomic locations. IMT of the lumbar spinal canal is exceptionally rare.

PATIENT CONCERNS

Here, we report the case of a 56-year-old male patient with an IMT who was in good health until 1 year prior to admission, when he began experiencing pain in both lower extremities and the lower back.

INTERVENTIONS

A space-occupying lesion in the lumbar canal was identified by magnetic resonance imaging and then surgically resected.

DIAGNOSES

Histopathological analysis of the lesion revealed a composition of mucous edema, inflammatory cells, collagenous fibers, and spindle cells that were diffuse and positive for smooth muscle actin and CD68; focal positive for vimentin and desmin; and negative for CD34 (marker of vascular endothelial cells), CD21, CD23, CD35, S-100, Epstein-Barr virus infection, Ki-67, and anaplastic lymphoma kinase. Thus, the diagnosis was an IMT of the lumbar canal.

OUTCOMES

In the spinal canal, IMT should be considered in the evaluation of tumors although it is a very rare diagnosis. It is a benign lesion, but it has potential for invasion and recurrence.

LESSONS

There are no characteristic imaging features of these tumors, but they can be addressed by complete surgical excision. Patients with these lesions should undergo frequent long-term follow-up to detect and address recurrence.

A Mesenteric Desmoid Tumor with Rapid Progression

We herein report the case of a rapidly progressive sporadic mesenteric desmoid tumor (DT). A 62-year-old woman presented with a 4-cm-diameter palpable mass in the left supraumbilical area. The mass showed an ill-defined margin with heterogeneous delayed enhancement on computed tomography and heterogeneous high intensity on T2-weighted magnetic resonance imaging. Sixteen months after the initial observation, the mass had grown in size, reaching 13 cm in diameter. The resected mass was histologically confirmed as a DT of the mesentery. Since DT often has an unpredictable clinical course, clinicians should bear in mind the need for imaging follow-up.

IgG4-related sclerosing mesenteritis causing bowel obstruction: a case report

Sclerosing mesenteritis (SM) is a rare inflammatory and fibrosing disease primarily involving the small-bowel mesentery. Recently, SM was reported to be closely related to IgG4-related disease (IgG4-RD). This report describes a patient with SM associated with IgG4-RD. A 77-year-old woman with a history of surgery for ectopic pregnancy and wound dehiscence presented with intestinal obstruction. Abdominal enhanced computed tomography (CT) revealed an enhanced, radially shaped, oval mass, 3 cm in diameter, with an unclear rim in the mesentery of the distal ileum, which may have involved the distal ileum. To remove the cause of bowel obstruction, the SM was resected completely and the ileum was resected partially. Histologic examination showed that the mass was composed of spindle cells arranged in a fascicular or storiform pattern; moreover, fibrous stroma was observed, with dense lymphoplasmacytic infiltration and lymphoid follicles. Immunohistochemically, numerous IgG4-positive plasma cells were observed, at a density of 253 per high-powered field, and the IgG4/IgG ratio was about 50 %. Elastica van Gieson (EVG) staining also showed obstructive phlebitis. These findings indicated IgG4-related SM. Although the accurate diagnosis of SM remains difficult without histological analysis, IgG4-RD should be included in the differential diagnosis of unknown mesenteric tumors. Identification of IgG4-RD may prevent unnecessary surgery because corticosteroids may be effective in these patients.

[Mesenteric panniculitis]

Mesenteric panniculitis is a condition characterized by chronic nonspecific inflammation of the mesentery. There is little and often confusing information about its characteristics and the approach to take once it has been demonstrated by an imaging test. We propose to describe the epidemiological, clinical, laboratory, radiological and pathological features of the patients with mesenteric panniculitis reported in the literature, as well as possible disorders causal or associated with mesenteric panniculitis, in the opinion of the authors of each study. Finally, we will review the different therapeutic options used and the response to them. To that end a literature search was performed from the main medical databases selecting ítems with information on these aspects. This information was collected on a database stored in SPSS software for further analysis and summary.

De-misty-fying the mesentery: an algorithmic approach to neoplastic and non-neoplastic mesenteric abnormalities

Mesenteric abnormalities are often incidentally discovered on cross-sectional imaging performed during daily clinical practice. Findings can range from the vague "misty mesentery" to solid masses, and the possible etiologic causes encompass a wide spectrum of underlying pathologies including infectious, inflammatory, and neoplastic processes. Unfortunately, the clinical and imaging findings are often non-specific and may overlap. This article discusses the various diseases that result in mesenteric abnormalities. It provides a framework to non-invasively differentiate these entities, when possible.

Highly Vascularized Primarily Inflammatory Pseudotumor of the Omentum in an Adult Male: A Case Report

Patient: Male, 38

Final Diagnosis: Inflammatory myofibroblastic tumor

Symptoms: Abdominal pain • anorexia • weight loss

Medication: —

Clinical Procedure: Operation

Specialty: Surgery

Rare Case Report Of Mesenteric Fibromatosis

Mesenteric fibromatosis is a part of the clinical-pathologic spectrum of deep fibromatoses. We report this rare case of primary mesenteric tumor that was diagnosed to be a mesenteric fibromatosis on histopathological examination. In majority of patients it may remain asymptomatic and the management of these tumors depends on histopathological examination. Postoperatively, patient was well and subsequent follow up showed normal recovery.

Solitary benign fibrous mesothelioma of the peritoneum: A rare entity in a 2-year-old child

Solitary benign fibrous mesothelioma (BFM) is uncommon and is termed as solitary fibrous mesothelioma or localized fibrous mesothelioma. Although the most common site for its development is the pleural region (65%), it has also been reported in the peritoneum. They are mostly seen in adults (average age: 54 years). Herein, we present a case of BFM in a 2-year-old male child, who presented to our hospital with abdominal pain and a lump in the abdomen. Differential diagnosis included solitary fibrous tumor, gastrointestinal stromal tumor, and benign fibrous lesions of mesentery. Establishing a preoperative diagnosis is difficult on the basis of clinical parameters or imaging studies and final diagnosis can only be assessed based on the results of histopathological and immunohistochemical examination.

Primary and secondary disease of the peritoneum and mesentery: review of anatomy and imaging features

The largest and most complex serosal membrane in the body, the peritoneum, lines the abdominal cavity, and the abdominopelvic viscera. It is frequently involved in a variety of benign and malignant processes. While secondary involvement of the peritoneum is more common, primary tumors can be a diagnostic challenge. Knowledge of the anatomy is crucial in understanding the various pathologic processes. Cross-sectional imaging plays an important role in diagnosing and evaluating the extent of the disease processes. This article reviews the imaging anatomy of the peritoneum and mesentery and the common pathologies involving it.

Inflammatory Pseudotumor (IPT) and Inflammatory Myofibroblastic Tumor (IMT): A Representative Literature Review Occasioned by a Rare IMT of the Transverse Colon in a 9-year-old Child

Aims and Background

Inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT) represent different entities. However, it is only in recent years that this has been taken into increasing consideration. Some authors still use both terms synonymously or interchangeably. Inflammatory myofibroblastic tumor is a real neoplasm because of the proliferation of myofibroblastic cells. Inflammatory pseudotumor is a more inflammatory reactive or regenerative entity and shows an overlapping with immunoglobulin G4-related disease.

Methods and Study Design

To analyze the current situation, 443 publications from the last 5 years (2009 to February 2014) were included. Reports involved 938 patients and 956 organ sites. The age distribution is twin peaked with one maximum in childhood and the other between 50 and 60 years of age. This distribution is questionable due to the more frequent occurrence of IPT in the liver and of IMT in the lung. Inflammatory pseudotumors mainly occur in older patients; IMTs in children and young adults.

Results and Conclusions

The liver and biliary tract were the most commonly affected of all body regions, at 32%. This was followed by the lung, including the respiratory tract, at 27%, and by the gastrointestinal tract, at 10%. Lesions of the large bowel, as in the present case of a 9-year-old boy, are very rare. There were organ-related as well as nonspecific clinical symptoms, such as fever, weight loss, and fatigue. Laboratory test results revealed anemia and elevated inflammation-dependent parameters. The patterns in medical imaging are variable and nonspecific. Morphology often suggests a malignant process. For this reason, therapy in most cases is surgical, but this is required more often in IMTs. Many IPTs could be treated conservatively.

Shedding light on inflammatory pseudotumor in children: spotlight on inflammatory myofibroblastic tumor

Inflammatory pseudotumor is a generic term used to designate a heterogeneous group of inflammatory mass-forming lesions histologically characterized by myofibroblastic proliferation with chronic inflammatory infiltrate. Inflammatory pseudotumor is multifactorial in etiology and generally benign, but it is often mistaken for malignancy given its aggressive appearance. It can occur throughout the body and is seen in all age groups. Inflammatory pseudotumor has been described in the literature by many organ-specific names, resulting in confusion. Recently within this generic category of inflammatory pseudotumor, inflammatory myofibroblastic tumor has emerged as a distinct entity and is now recognized as a fibroblastic/myofibroblastic neoplasm with intermediate biological potential and occurring mostly in children. We present interesting pediatric cases of inflammatory myofibroblastic tumors given this entity's tendency to occur in children. Familiarity and knowledge of the imaging features of inflammatory pseudotumor can help in making an accurate diagnosis, thereby avoiding unnecessary radical surgery.

Desmoid-type fibromatosis

Desmoid-type fibromatosis is a rare, locally infiltrative, mesenchymal neoplasm that is associated with high rates of local recurrence but lacks the potential to metastasise. The disease affects younger individuals, with a peak age of 30 years, and is the most common cause of an anterior abdominal wall mass in young women of childbearing age. It may, however, involve nearly every body part, including the extremities, head and neck, trunk, and abdominal cavity; as such, desmoid-type fibromatosis may present to a range of general and subspecialty radiologists. These rare tumours have a widely variable clinical presentation and unpredictable natural history, hence input from a soft-tissue tumour centre is recommended, although much of the imaging may be performed at the patient's local hospital. The consensus for treatment has changed over the past decade, with most centres moving away from primary radical surgery towards a front-line 'watch-and-wait' policy. Therefore, imaging has an increasingly important role to play in both the diagnosis and follow-up of these patients. This review will discuss the typical imaging characteristics of these lesions and suggest diagnostic and follow-up magnetic resonance imaging protocols, with details of suitable sequences and scanning intervals.