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

Beyond the benign: A rare case report of myxoid pleomorphic liposarcoma

Myxoid pleomorphic liposarcoma is a rare and aggressive subtype of soft tissue sarcomas (STS). It primarily arises from adipose tissue and exhibits a high rate of recurrence and metastatic potential. We report the case of a 35-year-old male gym trainer with a 5-month history of a painless, progressively enlarging mass on the right posterior aspect of chest, diagnosed with myxoid pleomorphic liposarcoma following imaging and histopathological evaluation of the excised specimen. Surgical excision with clear margins and adjuvant radiotherapy resulted in a favorable outcome with no recurrence at 7 months. This case emphasizes the importance of early diagnosis and multidisciplinary approach in managing a rare soft tissue sarcoma to prevent complications from a delayed intervention.

Pictorial Review of Soft Tissue Lesions with Calcification

Calcifications in soft tissue tumors present critical diagnostic challenges in musculoskeletal imaging. Their presence and morphology can provide key clues for differentiating benign from malignant lesions, influencing both prognosis and management strategies. This pictorial review aims to explore the imaging characteristics, patterns, and implications of soft tissue calcifications, with a focus on distinguishing between benign and malignant soft tissue tumors based on the World Health Organization classification. A systematic evaluation of imaging findings in various soft tissue tumor subtypes, including adipocytic, smooth muscle, vascular, chondro-osseous, and tumors of uncertain differentiation, is presented. Additionally, non-neoplastic causes of soft tissue calcifications, such as metabolic and inflammatory conditions, are reviewed for comprehensive differential diagnosis. Our review shows that the presence, distribution, and morphology of calcifications, such as stippled, punctate, coarse, and amorphous patterns, play a crucial role in tumor characterization. Some important examples are phleboliths, which strongly suggest a benign hemangioma, while dystrophic calcification is more commonly associated with malignant entities such as synovial sarcoma and dedifferentiated liposarcoma. Peripheral calcifications with zonal distribution are characteristic of myositis ossificans, whereas central dense calcifications may indicate extra-skeletal osteosarcoma. The review also discusses the significance of calcifications in non-neoplastic conditions, such as calcific tendinitis, tumoral calcinosis, and metabolic diseases, which can mimic soft tissue tumors. Recognizing the imaging characteristics of soft tissue calcifications is essential for accurate tumor classification and appropriate clinical management. This review highlights the importance of integrating radiologic findings with clinical and histopathological data to avoid misdiagnosis and unnecessary interventions.

Beyond the surface: A comprehensive radiological review of primary retroperitoneal neoplasms

Primary retroperitoneal neoplasms (PRNs) are a complex and diverse group of tumors arising in the retroperitoneal space, excluding those from retroperitoneal organs. These masses present significant diagnostic challenges due to their heterogeneous nature. PRNs primarily include sarcomas, neurogenic tumors, extragonadal germ cell tumors, and lymphomas, with the majority being malignant. This necessitates thorough evaluation by radiologists to assess resectability and the need for biopsy. Liposarcomas, the most common primary retroperitoneal sarcomas, and leiomyosarcomas, known for potential vessel involvement, exhibit distinct imaging patterns aiding differentiation. Neurogenic tumors, originating from nerve sheath, ganglionic, or paraganglionic cells, often appear in younger patients and have characteristic imaging features. Primary retroperitoneal extragonadal germ cell tumors are rare and are believed to originate from primordial germ cells that do not successfully migrate during embryonic development. Lymphomas are generally homogeneous on cross-sectional imaging; however, non-Hodgkin lymphomas can sometimes appear heterogeneous, complicating differentiation from other non-lipomatous retroperitoneal masses. Additionally, conditions like retroperitoneal fibrosis and Erdheim-Chester disease can mimic PRNs, complicating diagnosis and management. This review aims to provide radiologists with essential diagnostic points for identifying PRNs, emphasizing the importance of precise imaging interpretation. Understanding these distinctions is vital for guiding clinical management and optimizing patient outcomes.

Fibroblastic and Myofibroblastic Soft-Tissue Tumors: Imaging Spectrum and Radiologic-Pathologic Correlation

Fibroblastic and myofibroblastic tumors are a variable group of neoplasms ranging from benign to malignant. These lesions may affect patients of any age group but are more frequently encountered in the pediatric population. Patient clinical presentation depends on the location, growth pattern, adjacent soft-tissue involvement, and pathologic behavior of these neoplasms. In the 2020 update to the World Health Organization (WHO) classification system, these tumors are classified on the basis of their distinct biologic behavior, histomorphologic characteristics, and molecular profiles into four tumor categories: (a) benign (eg, fibrous hamartoma of infancy, nodular fasciitis, proliferative fasciitis, fibroma of the tendon sheath, calcifying aponeurotic fibroma); (b) intermediate, locally aggressive (eg, desmoid fibromatosis); (c) intermediate, rarely metastasizing (eg, dermatofibrosarcoma protuberans, myxoinflammatory fibroblastic sarcoma, low-grade myofibroblastic sarcoma, infantile fibrosarcoma); and (d) malignant (eg, sclerosing epithelioid fibrosarcomas; low-grade fibromyxoid sarcoma; myxofibrosarcoma; fibrosarcoma, not otherwise specified). Detection of various components of solid tumors at imaging can help in prediction of the presence of corresponding histopathologic variations, thus influencing diagnosis, prognosis, and treatment planning. For example, lesions with a greater myxoid matrix or necrotic components tend to show higher signal intensity on T2-weighted MR images, whereas lesions with hypercellularity and dense internal collagen content display low signal intensity. In addition, understanding the radiologic-pathologic correlation of soft-tissue tumors can help to increase the accuracy of percutaneous biopsy and allow unnecessary interventions to be avoided. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Perineum Spindle Cell Sarcoma in Neurofibromatosis Type 1

Soft tissue neoplasm is common among patients with neurofibromatosis type 1 (NF-1). We present a case of a middle-aged woman with NF-1 who presented with a painless, insidiously increasing perineal mass for the past eight months. She underwent colonoscopy, computed tomography staging, magnetic resonance imaging of the pelvis, core-needle biopsy, and later wide local excision of left perineum swelling. Histopathological examination showed a high-grade spindle cell sarcoma, which is a rare association among NF-1. Spindle cell sarcoma is a group of malignant soft tissue tumors with locally destructive growth with spindle-shaped neoplastic cells. The solitary spindle cell sarcoma of the perineum is rare, and wide local resection with a clear margin is the only treatment at present-the scarcely available evidence limiting the use of adjuvant chemotherapy, immunotherapy, and radiotherapy.

Multidisciplinary treatment of giant presacral solitary fibrous tumour: a case report and literature review

Solitary fibrous tumours (SFTs) usually occur at the pleura. Extrapleural sites, particularly giant extrapleural solitary fibromas, are more rarely observed in the clinic, and the clinical diagnosis and treatment of this disease is a focus of attention. Herein, the case of a 43-year-old male patient with giant presacral SFT successfully treated by open surgery, and with a final diagnosis confirmed by postoperative pathology and immunohistochemistry, is reported. The patient was followed-up regularly during 5 years after surgery, with no obvious surgical complications, and no tumour recurrence noted on pelvic magnetic resonance imaging. This case provides clinical information that may help in the diagnosis and treatment of complex SFT.

Surgical management of primary undifferentiated pleomorphic sarcoma of the rectum: a case report and review of the literature

Background

Undifferentiated pleomorphic sarcoma (UPS) is a malignant soft tissue tumor that has been reclassified from malignant fibrous histiocytoma with the development of the pathological diagnosis. It principally occurs in the extremities but rarely occurs in the rectum. We herein report a rare case of UPS arising in the rectum.

Case presentation

A 85-year-old woman was referred to our hospital with a complaint of anal pain, which had persisted for several months. Computed tomography (CT) showed a 53 × 58 × 75 mm mass on the left side of the rectum. Colonoscopy revealed a submucosal elevation in the rectum without any exposure of the tumor to the surface. Contrast-enhanced CT and magnetic resonance imaging revealed an 80-mm mass that originated in the rectal muscular propria, and we suspected a gastrointestinal stromal tumor. No lymph node metastasis or distant metastasis was observed. We performed a laparoscopic Hartmann’s operation. Intraoperatively, severe adhesion around the tumor caused tumor injury and right ureteral dissection. Thus, laparoscopic right ureteral anastomosis and ureteral stenting were additionally performed. The operation time was 6 h and 3 min, and the estimated blood loss was small. The patient was discharged without complications 25 days after surgery. A pathological examination showed that the tumor was composed of highly heterogeneous cells with no specific differentiation traits, leading to a diagnosis of UPS. Contrast-enhanced CT performed 2 months after surgery showed bilateral pelvic lymph node enlargement, which indicated recurrence. Considering the patient’s age, we performed radiotherapy (50 Gy/25 Fr targeting the pelvic region). At present, 16 months have passed since the completion of radiotherapy. Contrast-enhanced CT shows that the recurrent lymph nodes have disappeared, and no new distant metastasis has been observed.

Conclusions

We reported a case of UPS arising in the rectum. The surgical procedure and indication of preoperative therapy should be carefully selected because complete removal of the tumor is desirable in UPS.

Fat-containing pelvic lesions in females

Pelvic tumors are common in females and have a broad differential diagnosis. The clinical management of pelvic tumors varies widely-from observation to surgical resection-and imaging plays a pivotal role in diagnosis and clinical decision-making in these cases. In particular, imaging can help determine the organ of origin and tissue content of these tumors, which are the most important steps to narrowing the differential diagnosis. Fat has a characteristic appearance and is often easily identified on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). The amount and distribution of intralesional fat varies in different types of tumors. Macroscopic intralesional fat is often easily recognized by its hyperechoic appearance on US and low attenuation on CT similar to subcutaneous fat. On MRI, macroscopic fat is hyperintense on T1-weighted (T1W) images, with characteristic signal loss on fat-saturated sequences and India-ink artifact on opposed-phase T1W images. Macroscopic fat is the hallmark of teratomas, which are the most common ovarian neoplasms. Uterine lipoleiomyomas, peritoneal loose bodies, intraperitoneal and extraperitoneal primary lipomatous tumors such as lipoma and liposarcomas, and extra-adrenal myelolipomas are other pelvic masses distinguished by the presence of macroscopic fat. However, the imaging diagnosis of pelvic masses containing minimal or microscopic fat, such as immature ovarian teratomas, steroid cell ovarian neoplasms, and extramedullary hematopoiesis, can present a diagnostic challenge owing to their nonspecific appearance on US or CT. Obtaining MRI with in-phase and opposed-phase dual-echo T1W sequences and depicting chemical shift artifacts can be helpful in distinguishing these lesions.

OUP accepted manuscript

Primary adrenal pleomorphic spindle cell sarcoma (PSCS) is an exceedingly rare mesenchymal tumour that was previously known as malignant fibrous histiocytoma. It commonly occurs in extremities, retroperitoneum, peritoneal cavity and rarely in visceral organs. We report the first case of PSCS in the left adrenal gland in a 65-year-old female who presented with a large abdominal mass with vague symptoms. The wide range of differential diagnoses posed a challenge in establishing the diagnosis. However, this was overcome by appropriate radiological, intra-operative, histological and most importantly, comprehensive immunohistochemical findings. The patient underwent complete surgical resection of the tumour and had an unremarkable recovery. She remains without metastasis or recurrences to date through her 18 months of post-operative follow-up despite the poor prognosis of this tumour.

Rare Mesenchymal Tumors of the Pelvis: Imaging and Pathologic Correlation

Most pelvic tumors originate from the organs. Less commonly, tumors can arise from the various anatomic pelvic compartments and are comprised of mesenchymal tissue: muscles, connective tissue, vessels, lymphatics, and fat. Among some of the rarer entities are benign tumors (eg, angiomyxoma, cellular angiofibroma, and desmoid fibromatosis), malignant tumors (eg, sarcoma), and tumors that can manifest as benign or malignant (eg, solitary fibrous tumor or nerve sheath tumor). Because these tumors are uncommon and often manifest with nonspecific clinical features, imaging (usually MRI) is an initial step in the evaluation. Radiologists interpreting these images are asked to help narrow the differential diagnosis and assess the likelihood of malignancy for treatment planning. Thus, the MRI report should include the imaging features that would indicate the underlying tissue histology for pathologic diagnosis as well as a description of the anatomic extent and pattern of growth. The authors describe multiple locally aggressive benign and malignant mesenchymal tumors and highlight characteristic clinical and imaging features that enable the radiologist to narrow the differential diagnosis. The anatomic spaces of the pelvis are reviewed with illustrations to aid the radiologist in describing these tumors, which often span multiple pelvic compartments. Tumor appearance at T2-weighted, diffusion-weighted, and postcontrast MRI is summarized and illustrated with correlation at CT or fluorodeoxyglucose PET/CT, when available. MRI features that correspond to specific types of tissue (eg, myxoid, fibrous, or vascular) are highlighted and correlated with images from pathologic evaluation. Online supplemental material is available for this article. ^©RSNA, 2021.

Approach to Cystic Lesions in the Abdomen and Pelvis, with Radiologic-Pathologic Correlation

Cystic lesions found in and around the peritoneal cavity can often be challenging to diagnose owing to significant overlap in imaging appearance between the different entities. When the cystic lesion can be recognized to arise from one of the solid abdominal organs, the differential considerations can be more straightforward; however, many cystic lesions, particularly when large, cannot be clearly associated with one of the solid organs. Cystic lesions arising from the mesentery and peritoneum are less commonly encountered and can be caused by relatively rare entities or by a variant appearance of less-rare entities. The authors provide an overview of the classification of cystic and cystic-appearing lesions and the basic imaging principles in evaluating them, followed by a summary of the clinical, radiologic, and pathologic features of various cystic and cystic-appearing lesions found in and around the peritoneal cavity, organized by site of origin. Emphasis is given to lesions arising from the mesentery, peritoneum, or gastrointestinal tract. Cystic lesions arising from the liver, spleen, gallbladder, pancreas, urachus, adnexa, or soft tissue are briefly discussed and illustrated with cases to demonstrate the overlap in imaging appearance with mesenteric and peritoneal cystic lesions. When approaching a cystic lesion, the key imaging features to assess include cyst content, locularity, wall thickness, and presence of internal septa, solid components, calcifications, or any associated enhancement. While definitive diagnosis is not always possible with imaging, careful assessment of the imaging appearance, location, and relationship to adjacent structures can help narrow the differential diagnosis. Online supplemental material is available for this article. ^©RSNA, 2021.

Unexpected inferior vena cava syndrome: leiomyosarcoma

Leiomyosarcomas arising directly from the blood vessels are rare. These tumours are formed from the muscular wall of either a major vein or artery. The authors describe the case of an 84-year-old woman with lower back pain with bilateral abdominal irradiation and marked peripheral oedema, who was diagnosed with leiomyosarcoma of the inferior vena cava after biopsy of an infrahepatic mass. An endovascular prosthesis was placed as the patient was proposed for palliative care. Leiomyosarcomas of the inferior vena cava may present with non-specific symptoms. Therefore, the authors aim to draw attention to the diagnosis process, as well as imaging findings related to this pathology.

Giant Darier-Ferrand dermatofibrosarcoma protuberans of the abdomen and pelvis: a case report

Background

Darier–Ferrand dermatofibrosarcoma (DFS) is a rare malignant cutaneous neoplasm characterized by local aggressiveness, high risk of recurrence, and low metastatic potential.

Case presentation

A 60-year-old Tunisian man with recurrent abdominopelvic DFS for which he had undergone multiple excisions presented with an extensive DFS that invaded the external genitals. He underwent a large excision with emasculation and thin cutaneous graft of the abdominal wall and local skin flap in the pelvis.

Conclusion

DFS is a rare yet recurrent skin tumor. Wide excision with free margins remains the cornerstone of treatment. We report a case of a giant DFS treated with wide excision and reconstructive surgery to cover the defect.

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.

CT-Based Radiomics to Differentiate Pelvic Rhabdomyosarcoma From Yolk Sac Tumors in Children

Background

The purpose of this study was to investigate the role of CT radiomics features combined with a support vector machine (SVM) model in potentially differentiating pelvic rhabdomyosarcoma (RMS) from yolk sac tumors (YSTs) in children.

Methods

A total of 94 patients with RMS (n = 49) and YSTs (n = 45) were enrolled. Non-enhanced phase (NP), arterial phase (AP), and venous phase (VP) images were retrieved for analysis. The volumes of interest (VOIs) were constructed by segmenting tumor regions on CT images to extract radiomics features. Datasets were randomly divided into two sets including a training set and a test set. In the training set, the least absolute shrinkage and selection operator (LASSO) algorithm was used to screen out the optimal radiomics features that could distinguish RMS from YSTs, and the features were combined with the SVM algorithm to build the classifier model. In the testing set, the areas under the receiver operating characteristic (ROC) curves (AUCs), accuracy, specificity, and sensitivity of the model were calculated to evaluate its diagnostic performance. The clinical factors (including age, sex, tumor site, tumor volume, AFP level) were collected.

Results

In total, 1,321 features were extracted from the NP, AP, and VP images. The LASSO regression algorithm was used to screen out 23, 26, and 17 related features, respectively. Subsequently, to prevent model overfitting, the 10 features with optimal correlation coefficients were retained. The SVM classifier achieved good diagnostic performance. The AUCs of the NP, AP, and VP radiomics models were 0.937 (95% CI: 0.862, 0.978), 0.973 (95% CI: 0.913, 0.996), and 0.855 (95% CI: 0.762, 0.922) in the training set, respectively, which were confirmed in the test set by AUCs of 0.700 (95% CI: 0.328, 0.940), 0.800 (95% CI: 0.422, 0.979), and 0.750 (95% CI: 0.373, 0.962), respectively. The difference in sex, tumor volume, and AFP level were statistically significant (P < 0.05).

Conclusions

The CT-based radiomics model can be used to effectively distinguish RMS and YST, and combined with clinical features, which can improve diagnostic accuracy and increase the confidence of radiologists in the diagnosis of pelvic solid tumors in children.

Imaging Features of Neurofibromatosis Type 1 in the Abdomen and Pelvis

OBJECTIVE. Loss of the neurofibromatosis type 1 (NF1) tumor suppressor protein causes uninhibited activation of the RAS oncogene, which leads to tumorigenesis in patients with NF1. This case-based review discusses imaging manifestations of NF1 in the abdomen and pelvis, highlighting key genetic associations and management to elucidate features different from the general population. CONCLUSION. The spectrum of pathologic findings includes gastrointestinal tumors such as gastrointestinal stromal tumors, genitourinary lesions including urogenital neurofibromas, vascular entities such as renal artery stenosis, and less common associations like lymphoma.

Clinical and imaging characteristics of primary hepatic sarcomatoid carcinoma and sarcoma: a comparative study

Background

Primary hepatic sarcomatous carcinoma (PHSC) and primary hepatic sarcoma (PHS) are rare malignancies with frequent overlap in both the clinic and radiology. No comparative study of these tumors for the restricted cases has previously been undertaken. The purpose of our study was to analyze the clinical and imaging features of PHSCs and PHSs, with an emphasis on particularities and similarities through a comparison of the two tumors.

Methods

We retrospectively analyzed the clinical and imaging features of 39 patients with pathologically proven PHSCs (n = 23) and PHSs (n = 16) from four university centers over a 9-year period from 2010 to 2019. Univariate analyses were performed to determine the consistent and distinctive features.

Results

The background of chronic hepatitis or cirrhosis was observed with a high frequency in both of PHSCs (73.7%) and PHSs (62.5%). Tumors with a diameter greater than 10 cm were significantly more common in PHSs than PHSCs (p = 0.043) and cystic masses were more detected in PHSs (P = 0.041). Both PHSCs and PHSs mainly presented hypovascularity (78.3% vs 81.3%). The ring hyper enhancement on the arterial phase (AP) and wash out were more frequently seen in PHSCs and the iso-hypo enhancement on the AP followed persistent or progressive enhancement was more commonly detected in PHSs (all, p < 0.05).

Conclusion

PHSC and PHS generally present as mass lesions with hypovascularity. The ring hyper enhancement on the AP and wash out favor the diagnosis of PHSC. The large size greater than 10 cm, cystic lesion, iso-hypo persistent or progressive enhancement pattern might suggest the possibility of PHSs.

Fat-Finding Mission: Primary Pleomorphic Liposarcoma of the Heart and Pericardium

Primary cardiac liposarcomas are rare tumors with a poor prognosis and no well-defined imaging characteristics or treatment guidelines. Here, we present a case of primary pleomorphic liposarcoma of the heart and pericardium with multimodality imaging findings and our institution’s treatment approach. (Level of Difficulty: Intermediate.)

Mesenteric Amyloidosis: Radiologic Imaging with Pathologic Correlation

Amyloidosis is a rare disease that is characterized by abnormal deposition of amyloid proteins in tissues, resulting in local, or systemic disease. When localized, it can present as an amyloidoma. We report a case of mesenteric amyloidosis in an 80-year-old male who was found to have an incidental mesenteric mass that was biopsy-proven to represent non-light chain amyloid tissue.

Calcified Splenic Lesions: Pattern Recognition Approach on CT With Pathologic Correlation

OBJECTIVE. Incidental splenic lesions, often found on CT images of the abdomen, may often be ignored or mischaracterized. Calcified splenic lesions are often presumed to be granulomas; however, understanding the broader differential diagnostic considerations can be useful. CONCLUSION. Determining the cause of splenic lesions is essential to guide appropriate management; the pattern of calcification together with other imaging and clinical findings can aid with differentiation.

Comprehensive Review of Abdominopelvic Mesenchymal Tumors With Radiologic Pathologic Correlation and Update on Current Treatment Guidelines-Part 2

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 treatment options available helps 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.

CT and MRI features of tumors and tumor-like lesions in the abdominal wall

Masses involving the abdominal wall are common in clinical practice and have many etiologies, including tumors and tumor-like lesions. Abdominal wall tumors include primary and secondary tumors, the former of which constitute a heterogeneous group of soft tissue tumors with their own unique spectrum. Tumor-like lesions, such as hernias, are more common and must be distinguished from true tumors. Medical imaging is valuable for discovering, diagnosing, and evaluating the extent of abdominal wall masses. With the increasing application of computed tomography (CT) and magnetic resonance imaging (MRI), determining a diagnosis or narrowing the differential diagnosis is often possible, thus facilitating effective management. In this article, we comprehensively review the spectrum of common abdominal wall masses and present the CT and MRI features of typical cases in our hospital. A systematic stepwise diagnostic approach is also proposed for clinical practice.

Osteosarcomatous Divergence in Dedifferentiated Liposarcoma Presenting as a Colonic Mass

Dedifferentiated liposarcomas most commonly arise in the retroperitoneum, accounting for 10% of liposarcomas. Heterologous differentiation occurs in 5-10% of dedifferentiated liposarcomas; however, divergent osteosarcomatous differentiation is rare. We report a rare case of initial presentation of dedifferentiated liposarcoma with osteosarcomatous component as a colonic mass in a 72-year-old man. The tumor is mainly composed of bony trabeculae with intervening highly atypical cells and adjacent high-grade mesenchymal nonlipogenic tumor, as well as areas of well-differentiated liposarcoma. Immunohistochemical studies showed diffuse positivity for SATB2 in the atypical cells and fluorescence in situ hybridization revealed high-level amplification of MDM2 gene, supporting the diagnosis of well-differentiated and dedifferentiated liposarcoma with heterologous osteosarcomatous differentiation.

Ischiorectal fossa: benign and malignant neoplasms of this "ignored" radiological anatomical space

PURPOSE

To review the pertinent anatomy and the imaging features of common and uncommon benign and malignant neoplasms and masses of the ischiorectal fossa.

RESULTS

The ischiorectal or ischioanal fossa is the largest space in the anorectal region. The benign neoplasms that develop in the ischiorectal originate from the different components that forms the fossa including vascular tumors such as aggressive angiomyxoma or hemangioma; neural tumors as plexiform neurofibroma or schwannoma; fat tumors as lipoma; skin/skin appendages tumors as hidradenoma papilliferum; smooth or skeletal muscle tumors as solitary fibrous tumor. The malignant neoplasms that develop in the ischiorectal fossa also originate from different components that forms the fossa including vascular tumors such as angiosarcoma, neural tumors as malignant granular cell tumor and malignant peripheral nerve sheath tumor; fat tumors as liposarcoma; smooth or skeletal muscle tumors as leiomyosarcoma, rhabdomyosarcoma, malignant PEComa, or undifferentiated pleomorphic sarcoma. Additionally, the ischiorectal fossa can also harbor secondary hematogenous metastases and be affected by direct invasion from neoplasms of adjacent pelvic organs and structures. Furthermore, other miscellaneous masses can occur in the ischiorectal fossa including congenital and developmental lesions, and inflammatory and infectious processes.

CONCLUSION

Knowledge of the anatomy, and the spectrum of imaging findings of common and uncommon benign and malignant neoplasms of the ischiorectal fossa is crucial for the radiologists during interpretation of images allowing them to make contributions to the diagnosis and better patient management.

Angiographic evaluation of the internal iliac artery branch in pelvic tumour patients: Diagnostic performance of multislice computed tomography angiography

The aim of the present study was to explore the classification of the internal iliac artery (IIA) and the diagnostic value of the pelvic tumour-feeding artery by multislice computed tomography angiography (MSCTA) compared with digital subtraction angiography (DSA). A total of 43 patients with pelvic tumours were enrolled between January 2013 and August 2017. The classification of the IIA and the quality of the feeding artery of the pelvic tumours were analysed by Yamaki's classification (Groups A-D according to IIA branching) and the 5-point scoring system. The degree of feeding artery stenosis, caused by tumour compression or invasion, was analysed by a 4-point scoring system. The Wilcoxon signed-rank test was used to determine the vascular diagnostic quality identified by MSCTA and DSA. MSCTA of the pelvic arteries was successfully performed in all patients. The main classifications of the IIA were Group A, followed by Group C, then Group B and with no cases of Group D. There was no significant difference in the classification of the IIA between the left and right sides on MSCTA and DSA. The visualization quality of the IIA and its main branches showed excellent consistency, but the difference in the terminal branches of the feeding arteries in the pelvic tumours was statistically significant between MSCTA and DSA. MSCTA has great advantages in evaluating the classification of the IIA, the imaging quality evaluation of the IIA and its main branches, and in the evaluation of the pelvic tumour-feeding artery. However, in the display of the terminal arterial branches of the pelvic tumours, DSA remains irreplaceable, particularly in cases of interventional embolization.

Primary hepatic leiomyosarcoma presenting as a thick-walled cystic mass resembling a liver abscess: A case report

RATIONALE

Hepatic leiomyosarcoma is a rare malignant tumor, and in rare instances, its combination with fever may lead to misdiagnosis of liver abscess. In our case, the presence of the tumor was considered by the presence of blood vessels through the observation of hepatic tumor wall.

PATIENT CONCERNS

A 38-year-old woman who had been diagnosed with a liver abscess in a local hospital consulted our institution by complaining left upper quadrant pain and fever. The diagnosis was questioned in our workup, since no obvious inflammatory marker was found in the circulation, and contrast-enhanced computed tomography revealed a huge thick-walled mass in the right liver with multiple tortuous vessels within the wall.

DIAGNOSIS

Imaging revealed a neoplastic lesion rather than liver abscess. The enhancement of the solid tumor tissues was reduced during the portal phase and delayed phase, which was consistent with a wash-out enhancement. The histopathologic and immunohistochemical results confirmed the diagnosis was primary hepatic leiomyosarcoma. A pulmonary nodule during the postoperative follow-up was diagnosed as metastatic leiomyosarcoma tumor through surgery.

INTERVENTIONS

A right hepatectomy was performed to cure the hepatic mass. In the follow-up, a metastatic tumor in the lung was resected, followed by chemotherapy.

OUTCOMES

Lung metastasis and liver recurrence occurred at 25 and 39 months after liver surgery, respectively. Then the patient was lost to follow-up.

LESSONS

Leiomyosarcoma is associated with a dismal prognosis, but outcomes for these patients may be improved by the combined surgical resection and chemotherapy.

A PET-positive rapidly growing mass of the abdominal wall after cesarean section with an unexpected diagnosis of vernix caseosa granuloma: a case report

Background

Abdominal wall tumors are rare and include heterogeneous diseases. Among them, desmoid tumors are the most frequent and are often diagnosed in young women during or early after pregnancy; inflammatory response after trauma or microtrauma, such as after cesarean section, may favor their growth.

Results

A 37-year-old woman presented with a progressive mass in the abdominal wall after a cesarean section. Positron emission tomography imaging confirmed a positive mass with a high maximum standardized uptake value; a biopsy suggested a myofibroblastic tumor. With continued tumor growth and worsening symptoms, the mass resembled a desmoid tumor; therefore, we proceed with its resection. The final diagnosis was foreign body granuloma as a reaction to the spillage of meconium and keratinous material in the amniotic fluid during cesarean section.

Conclusions

The present case provides information on an abdominal wall foreign body granuloma arisen from meconium and vernix caseosa after cesarean section, which presented an atypical clinical picture, mimicking a desmoid, thus requiring a careful diagnostic and treatment approach.

Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review

Abstract

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders. Gastrointestinal manifestations of NF-1 are seldom thought of in routine clinical practice and might thus be significantly under-recognised. Their heterogeneous spectrum ranges from localised microscopic proliferative lesions to grossly recognizable mass-forming neurofibromas, neuroendocrine and gastrointestinal stromal tumours (GIST). The aim of this study is discussing the imaging evaluation and characterisation of the abdomen lesions in patients with NF1.

Teaching Points

• Neurofibromatosis type (NF-1) is one of the most common single gene disorders.

• Every organ system can be involved and intra-abdominal manifestations are underestimated.

• The NF1 abdominal manifestations comprehend five categories of tumours.

• Neurogenic tumours including with neurofibromas are the most common type.

• Early diagnosis of abdominal manifestations of NF-1 based on imaging patterns is necessary for appropriate treatment to avoid serious organic complications related to tumour mass.

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.

[Borderline and malignant mesenchymal tumors of the abdomen]

BACKGROUND

Soft tissue sarcomas are most common mesenchymal malignancies in the abdomen. Their radiologic features are often unspecific and establishing a differential diagnosis to other pathologies can be difficult.

OBJECTIVES

This review presents a selection of the most common mesenchymal abdominal tumors and their imaging characteristics, as well as the associated differential diagnoses. Knowledge of fundamental pathologic, anatomic and radiologic features of these malignancies is crucial for the differential diagnosis and key in clinical decision making and subsequent selection of an appropriate therapeutic regimen.