Soft-Tissue Sarcomas of the Abdomen and Pelvis: Radiologic-Pathologic Features, Part 1-Common Sarcomas: From the Radiologic Pathology Archives

Oncological Outcome After Diagnostic Biopsies in Gastrointestinal Stromal Tumors: A Retrospective Cohort Study

OBJECTIVE

To analyze whether the route of preoperative biopsy influences oncological outcome in GIST patients.

SUMMARY OF BACKGROUND DATA

Preoperative biopsies are widely used for diagnosing GIST. Little is known about the risk of tumor seeding after different routes of biopsy.

METHODS

Patients who underwent resection of a primary GIST between 1996 and 2014 were identified from 2 databases from 2 tertiary referral centers. Survival data were obtained using the Kaplan-Meier method. Possible confounders were identified using Cox regression analysis. The primary endpoint was local recurrence free survival (RFS) and the secondary endpoint was DSS.

RESULTS

A total of 228 patients were included, with a median age of 62 years (range 17-86) and a median follow-up time of 53 months (range 1-204). From these patients, 42 patients did not have a biopsy (18%), 70 underwent a transcutaneous biopsy (31%), and 116 a transluminal biopsy (51%). A total of 42 patients (19.0%) had a local and/or distant recurrence. From the 70 patients with a transcutaneous biopsy, only 1 patient developed a needle tract recurrence (1.4%). Local RFS and DSS were both significantly shorter in the transcutaneous biopsy group on univariate analysis compared to the other groups; however, in multivariate analysis the route of biopsy did not influence local RFS (P = 0.128) or DSS (P = 0.096).

CONCLUSIONS

Transluminal or transcutaneous biopsies for diagnosing GIST do not significantly alter the risk of local recurrent disease or DSS in multivariate Cox regressions. The risk of needle tract seeding after transcutaneous biopsy was low.

A challenging diagnosis of mesenchymal neoplasm of the colon: colonic dedifferentiated liposarcoma with lymph node metastases-a case report and review of the literature

PURPOSE

We report a case of primitive colonic dedifferentiated liposarcoma along with lymph node metastases.

METHODS

The patient's clinical, radiologic, surgical, and histologic data were reviewed, as well as the literature on colonic dedifferentiated liposarcoma with a focus on the incidence of lymph node metastasis in gastrointestinal sarcomas and on the differential diagnosis with other spindle cell tumors in the gastrointestinal tract.

RESULTS

A 53-year-old man was referred to our hospital with a 3 year-history of pain on the right back that was refractory to drugs. He performed an abdominal computed tomography scan which revealed a colonic wall thickening in the hepatic flexure and a few serosal nodularities. With these findings, the patient underwent an extended right hemicolectomy. On histopathologic examination, it turned out to be a colonic dedifferentiated liposarcoma with lymph node metastases.

CONCLUSIONS

The present case was a challenging diagnosis both at presurgical and histopathological level because it strongly mimicked a colonic adenocarcinoma. This was due to non-specific clinical and radiological presentation, to the non-characteristic histologic morphology and to the misleading presence of lymph node metastases. Malignant stromal tumors of the gastrointestinal tract beyond gist are fairly rare entities. Colonic dedifferentiated liposarcoma must be kept in mind and must be considered in the differential diagnosis of gastrointestinal tumors.

Update in pelvic and retroperitoneal sarcoma management: The role of compartment surgery

Surgery for retroperitoneal sarcomas should be "en bloc" compartmental, which involves resection of unaffected organs. Its upfront use is key, providing a high percentage of resections with negative margins, resulting in a better local control and increased survival in many patients. Preservation of organs should be done in an individualized manner, especially in the pelvic location, and adapted to the histological aggressiveness of the tumor. Preoperative biopsy is able to establish the diagnosis of sarcoma subtype and consequently an adequate perioperative strategy. These patients should be managed by expert surgeons at referral centers with multidisciplinary units and oncology committees. The use of chemotherapy and radiotherapy is not yet well defined, so it is only recommended at referral centers with clinical trials. Currently, this is the only option to offer the best morbidity and mortality rates, as well as possible improvements in the survival of these patients.

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.

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.

Atypical lipomatous tumor in the ligamentum teres of liver: A case report and review of the literature

A 61-year-old male was referred to our hospital with a three-month history of persistent epigastralgia and right hypochondralgia. Initial examination revealed a fist-size mass at the epigastric fossa. Ultrasonography showed a hemangioma and a mosaic echoic lesion in the ventromedian with poor blood-flow signal and linear hyperechoic part inside, and a clear border to the surroundings. Dynamic computed tomography revealed a highly enhanced effect from the portal-venous phase continuing to the equilibrium phase. T1-weighted gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced image revealed a high intensity effect at the early phase that continued to the next phase. On the other hand, it contained a low intensity area by a fat suppression of that image. In addition, a T2-weighted image did not show a high intensity effect. Laparotomy was performed on the second day of hospitalization. The tumor had arisen from the ligamentum teres of the liver, and no metastasis or invasion of other organs was noted. It consisted of a lipid component of mature adipocytes and a fibrous component of deep dyeing pleomorphic or multinuclear atypical stromal cells. Immunohistochemical study of the atypical stromal cells demonstrated that they were positive for MDM2 and CDK4. A pathological diagnosis of atypical lipomatous tumor (ALT) was made, and the patient was discharged on the eighth day following the procedure. At the 6-mo follow-up dynamic CT, the patient was free of recurrence or metastasis. We experienced a patient with ALT in the ligamentum teres of the liver. This case suggests the need for a careful and detailed examination when encountering patients presenting with a mass; when neoplastic lesion is confirmed by image inspection, we should thoroughly investigate, including further image investigations and pathologic examination. The latter is the most important.

Embryonal rhabdomyosarcoma within abdomen and pelvis in an adult

Rhabdomyosarcoma arising in abdomen and pelvis is an uncommon but important type of soft tissue sarcoma, posing a great challenge for clinicians. Sporadic cases of intra-abdominal rhabdomyosarcoma were reported, but mostly in pediatrics. We demonstrated a rare case of primary abdominopelvic rhabdomyosarcoma in an elderly woman who presented with a notable increase in abdominal circumference and constipation. Abdominal magnetic resonance imaging showed a huge mass throughout the abdomen and pelvis. Cytoreductive surgery was performed by gynecologists due to the suspicious diagnosis of disseminated leiomyosarcoma. However, the final pathological analysis revealed embryonal rhabdomyosarcoma. Although adjuvant chemotherapy was administered, localized recurrence was identified 6 months after the initial operation. Gynecologists and radiologists should be aware of it so it can be listed in the differential diagnosis of masses that primarily arise in the abdomen and pelvis.

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.

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.