Imaging features and metastatic pattern of non-IVC retroperitoneal leiomyosarcomas: are they different from IVC leiomyosarcomas?

Leiomyosarcoma of the abdomen and retroperitoneum; a systematic review

Background

Intraabdominal and retroperitoneal leiomyosarcomas are rare cancers, which cause significant morbidity and mortality. Symptoms, treatment and follow up differs from other cancers, and proper diagnosis and treatment of intraabdominal and retroperitoneal leiomyosarcomas is of utmost importance. We performed a systematic review to collect and summarize available evidence for diagnosis and treatment for these tumours.

Methods

We performed a systematic literature search of Pubmed from the earliest entry possible, until January 2021. Our search phrase was (((((colon) OR (rectum)) OR (intestine)) OR (abdomen)) OR (retroperitoneum)) AND (leiomyosarcoma). All hits were evaluated by two of the authors.

Results

Our predefined search identified 1983 hits, we selected 218 hits and retrieved full-text copies of these. 144 studies were included in the review.

Discussion

This review summarizes the current knowledge and evidence on non-uterine abdominal and retroperitoneal leiomyosarcomas. The review has revealed a lack of high-quality evidence, and randomized clinical trials. There is a great need for more substantial and high-quality research in the area of leiomyosarcomas of the abdomen and retroperitoneum.

Systematic Review Registration

PROSPERO, identifier, CRD42023480527.

A Contemporary Clinicopathologic Analysis of Primary Sarcomas of the Perinephric Soft Tissue and Hilar Vessels Including a Subset Secondarily Involving the Kidney

A variety of primary malignant mesenchymal neoplasms can arise from the perinephric soft tissue and hilar vessels and potentially involve the kidney, mimicking primary renal tumors. A search was made at our institution for patients that underwent radical nephrectomy with associated perinephric or hilar sarcomas from 2010 to 2021. Twenty-six patients were identified. Mean patient age was 60 years (range: 34-83 years), with 16 (62%) females and 10 (38%) males. The mean tumor size was 21.6 cm (range: 8.1-36.5 cm). Among the perinephric/retroperitoneal sarcomas, 14/20 (70%) were dedifferentiated liposarcoma, 4/20 (20%) were well-differentiated liposarcoma, and 2/20 (10%) were leiomyosarcoma. There were 4 grade 1 (20%; all well-differentiated liposarcoma), 9 grade 2 (45%), and 7 grade 3 (35%) tumors. All 6 sarcomas arising from the renal vein/inferior vena cava were leiomyosarcoma: grade 2 in 1 (17%), grade 3 in 4 (67%), and ungraded (due to neoadjuvant therapy effect) in 1 (17%) patient. Four of the 26 (15%) tumors involved the ipsilateral kidney. All 4 tumors were grade 3 sarcomas. On follow-up, 8/26 (31%) patients developed local recurrence and/or metastasis. The mean time for recurrence was 22 months (range: 7-48 months). Two patients progressed with metastasis to the lungs, both of which were grade 3 leiomyosarcoma, and appeared 11 months after the initial diagnosis. Our data suggest that while local recurrence is prevalent with most subtypes of perinephric sarcomas, high-grade leiomyosarcoma has a distinct proclivity for distant metastasis, with the lungs being the most common site.

Understanding a mass in the paraspinal region: an anatomical approach

The paraspinal region encompasses all tissues around the spine. The regional anatomy is complex and includes the paraspinal muscles, spinal nerves, sympathetic chains, Batson's venous plexus and a rich arterial network. A wide variety of pathologies can occur in the paraspinal region, originating either from paraspinal soft tissues or the vertebral column. The most common paraspinal benign neoplasms include lipomas, fibroblastic tumours and benign peripheral nerve sheath tumours. Tumour-like masses such as haematomas, extramedullary haematopoiesis or abscesses should be considered in patients with suggestive medical histories. Malignant neoplasms are less frequent than benign processes and include liposarcomas and undifferentiated sarcomas. Secondary and primary spinal tumours may present as midline expansile soft tissue masses invading the adjacent paraspinal region. Knowledge of the anatomy of the paraspinal region is of major importance since it allows understanding of the complex locoregional tumour spread that can occur via many adipose corridors, haematogenous pathways and direct contact. Paraspinal tumours can extend into other anatomical regions, such as the retroperitoneum, pleura, posterior mediastinum, intercostal space or extradural neural axis compartment. Imaging plays a crucial role in formulating a hypothesis regarding the aetiology of the mass and tumour staging, which informs preoperative planning. Understanding the complex relationship between the different elements and the imaging features of common paraspinal masses is fundamental to achieving a correct diagnosis and adequate patient management. This review gives an overview of the anatomy of the paraspinal region and describes imaging features of the main tumours and tumour-like lesions that occur in the region.

Current update on IVC leiomyosarcoma

Primary leiomyosarcoma of the inferior vena cava (IVC) is a rare soft tissue sarcoma associated with poor prognosis. Patients are often asymptomatic or present with nonspecific abdominal symptoms, which delays initial diagnosis and contributes to poor oncologic outcome. Key imaging modalities include ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). Characteristic imaging features include imperceptible caval lumen, dilation of the IVC, heterogeneous enhancement of the tumor, and development of extensive collateral circulation. Surgical resection is the mainstay of treatment, while chemotherapy and/or radiation may serve as therapy adjuncts. This article reviews the pathology, clinical findings, imaging features and management of IVC leiomyosarcoma.

Radiologic-Pathologic Correlation of Primary Retroperitoneal Neoplasms

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

Potential application value of PET/computed tomography in retroperitoneal leiomyosarcoma and a literature review

OBJECTIVE

To analyze the fluorine-18 fludeoxyglucose PET/computed tomography (18F-FDG PET/CT) findings of retroperitoneal leiomyosarcoma (RLMS) and the role of this method in differentiating between benign and malignant masses and classifying the malignant degree to improve the understanding of this rare disease.

METHODS

Eight leiomyomas (A group), 13 RLMSs (B group), and 20 postoperative recurrence/metastasis RLMSs (C group) were enrolled. PET/CT features of B group were analyzed. The differences of metabolic parameters between three groups were compared, receiver operating characteristic (ROC) curve analysis was performed to group A and B, and correlation analysis was performed to subgroup B.

RESULTS

(1) The RLMS patients were more likely to be female, and PET/CT showed a high degree of heterogeneous metabolism in the soft tissue mass. (2) The standardized uptake value (SUV) of RLMS were significantly higher than those of benign leiomyomas (P < 0.05). The area under the ROC curve was 0.909, the sensitivity and specificity for diagnosing RLMS were 0.923 and 0.750, respectively, The SUVmax and SUVstd of primary RLMS were moderately associated with the Ki67 index. The mean SUVmax in the G1, G2 and G3 subgroups increased successively (4.15 ± 0.35, 6.47 ± 0.83, and 10.13 ± 4.29, respectively). (3) Primary RLMS was characterized by local invasion, but hematogenous metastasis and lymph node metastasis were rare. Postoperative recurrence/metastasis of RLMS was characterized by local recurrence and hematogenous metastasis, but lymph node metastasis was rare.

CONCLUSION

PET/CT has potential value in the preoperative staging, benign and malignant differentiation, malignant degree classification and postoperative follow-up of RLMS.

Leiomyosarcoma of the inferior vena cava. Our experience and a review of the literature

Leiomyosarcoma (LMS) of the inferior vena cava (IVC) is a rare malignant tumor, accounting for 2% of all LMSs. Less than 400 cases have been reported in literature. Computed tomography (CT) is the most accurate imaging method in assessing the location of the tumor within the IVC and magnetic resonance imaging (MRI) accurately identifies its extent and the potential for surgical resection. We present the case of a patient with inferior vena cava leiomyosarcoma (IVCL), for whom the pathological diagnosis was different from the initially expected one, the tumor appearance on pre-operative imaging mimicking renal cell carcinoma. The intraoperative difficulty of approaching renal hilum and IVC was a factor suggesting the vascular origin of the tumor, which was confirmed at pathological analysis. The extensive defect in the IVC after tumor excision led to the decision of complete transverse suturing of IVC, as significant collateral venous circulation was already present. Because IVCL is a rare disease, there is scarce data regarding the prognosis and treatment options. Long-term survival depends on the extent of the surgery. The need of vascular reconstruction is not always mandatory. Despite high recurrence rates, no consensus regarding adjuvant treatment exists yet. A multidisciplinary approach including surgical oncologists and vascular surgeons is mandatory to achieve the best patient outcomes. Perioperative planning, coordination and adherence to oncological techniques are critical.

Diagnostic approach to primary retroperitoneal pathologies: what the radiologist needs to know

Retroperitoneal soft tissue lesions represent a wide range of disease processes with overlapping imaging findings. Familiarity with the CT and MR characteristics of these conditions is important to guide clinical evaluation. We review the tissue types, characteristic clinical, demographic, and imaging features of retroperitoneal tumors and tumor-like non-neoplastic conditions with CT and MR correlation, including anatomic and imaging clues, and provide a diagnostic approach to aide the radiologist in making a specific diagnosis.

Inoperable Left Renal Vein Leiomyosarcoma Refractory to Chemotherapy Invades Inferior Vena Cava and Right Atrium: A Case Report

Mesenchymal stem cells differentiate into a plethora of cell types. These differentiated cell types include osteoblasts, chondrocytes, myocytes, and adipocytes. Sarcomas occur secondary to malignant transformation of these mesenchymal, pluripotent stem cells. Involuntary smooth muscle is responsible for the make up of hollow organs and vasculature in our body and is regulated by our autonomic nervous system, hormones, as well as chemical and local mediators. Cancer involving smooth muscle cells is designated as leiomyosarcoma (LMS). LMS can arise from any location in the body where smooth muscle is present and is frequently reported in the abdomen and pelvis, as well as the trunk, extremities, and throughout the retroperitoneum. 

Leiomyosarcoma: a rare presentation as multifocal lesion

Leiomyosarcoma is a rare type of connective tissue cancer, accounting for 5–10% of all soft tissue sarcomas. We present a case of leiomyosarcoma as unusual multifocal presentation. Retroperitoneal, mediastinal, pulmonary, uterine and bony regions were all involved at the time of presentation. The liver was normal without detected lesions.

Case of primary hepatic leiomyosarcoma successfully treated with laparoscopic right hepatectomy

We describe the case of a 77-year-old woman, presenting with non-specific epigastric pain. Physical examination and subsequent imaging revealed the presence of a large mass in the right liver lobe. This was shown to be a leiomyosarcoma on biopsy histology. Further investigation confirmed this to be a primary hepatic leiomyosarcoma with no evidence of metastases. The patient underwent successful surgical resection. She is currently under imaging follow-up, with no evidence of disease recurrence.

Retroperitoneal Leiomyosarcoma From the Radiologic Pathology Archives

Leiomyosarcoma is a malignant neoplasm that shows smooth muscle differentiation. It is the second most common sarcoma to affect the retroperitoneum. Retroperitoneal leiomyosarcomas may grow to large sizes before detection and may be an incidental finding at imaging. When symptomatic, retroperitoneal leiomyosarcoma may cause compressive symptoms, including pain. Retroperitoneal leiomyosarcoma most commonly manifests as a large soft-tissue mass, with areas of necrosis. The most frequent pattern of growth is an entirely extravascular mass. Less commonly, leiomyosarcoma may demonstrate both extravascular and intravascular components. Rarely, retroperitoneal leiomyosarcomas are completely intravascular, typically arising from the inferior vena cava. Given its variable imaging features, a large variety of neoplastic and nonneoplastic conditions are included in the differential diagnosis of retroperitoneal leiomyosarcoma. In this review, the authors discuss retroperitoneal leiomyosarcoma, with emphasis on the pathologic basis of disease, and illustrate the multimodality imaging appearances of retroperitoneal leiomyosarcoma using cases from the Radiologic Pathology Archives of the American Institute for Radiologic Pathology. The authors review important differential considerations of retroperitoneal leiomyosarcoma, focusing on the extravascular pattern of growth, and emphasize clinical and imaging features that help radiologists differentiate leiomyosarcoma from the most frequent mimics. The information presented in this review will aid radiologists in fulfilling their key roles in the diagnosis, operative planning, and follow-up of patients with retroperitoneal leiomyosarcoma.

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.

Imaging in Soft Tissue Sarcomas: Current Updates

Soft tissue sarcomas (STS) are heterogeneous malignant tumors that have nonspecific imaging features. A combination of clinical, demographic, and imaging characteristics can aid in the diagnosis. Imaging provides important information regarding the tumor extent, pretreatment planning, and surveillance of patients with STS. In this article, we illustrate the pertinent imaging characteristics of the commonly occurring STS and some uncommon sarcomas with unique imaging characteristics.

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

Soft-tissue sarcomas are a diverse group of rare mesenchymal malignancies that can arise at any location in the body and affect all age groups. These sarcomas are most common in the extremities, trunk wall, retroperitoneum, and head and neck. In the adult population, soft-tissue sarcomas arising in the abdomen and pelvis are often large masses at the time of diagnosis because they are usually clinically silent or cause vague or mild symptoms until they invade or compress vital organs. In contrast, soft-tissue sarcomas arising from the abdominal wall come to clinical attention earlier in the course of disease because they cause a palpable mass, abdominal wall deformity, or pain that is more clinically apparent. The imaging features of abdominal and pelvic sarcomas and abdominal wall sarcomas can be nonspecific and overlap with more common pathologic conditions, making diagnosis difficult or, in some cases, delaying diagnosis. Liposarcoma (well-differentiated and dedifferentiated liposarcomas), leiomyosarcoma, and gastrointestinal stromal tumor (GIST) are the most common intra-abdominal primary sarcomas. Any soft-tissue sarcoma can arise in the abdominal wall. Knowledge of the classification and pathologic features of soft-tissue sarcomas, the anatomic locations where they occur, and their cross-sectional imaging features helps the radiologist establish the diagnosis or differential diagnosis so that patients with soft-tissue sarcomas can receive optimal treatment and management. In part 1 of this article, the most common soft-tissue sarcomas (liposarcoma, leiomyosarcoma, and GIST) are reviewed, with a discussion on anatomic locations, classification, clinical considerations, and differential diagnosis. Part 2 will focus on the remainder of the soft-tissue sarcomas occurring in the abdomen and pelvis.

Current Concepts in Non-Gastrointestinal Stromal Tumor Soft Tissue Sarcomas: A Primer for Radiologists

Non-gastrointestinal stromal tumor (GIST) soft tissue sarcomas (STSs) are a heterogeneous group of neoplasms whose classification and management continues to evolve with better understanding of their biologic behavior. The 2013 World Health Organization (WHO) has revised their classification based on new immunohistochemical and cytogenetic data. In this article, we will provide a brief overview of the revised WHO classification of soft tissue tumors, discuss in detail the radiology and management of the two most common adult non-GIST STS, namely liposarcoma and leiomyosarcoma, and review some of the emerging histology-driven targeted therapies in non-GIST STS, focusing on the role of the radiologist.