Pleomorphic spindle cell sarcoma (PSCS) formerly known as malignant fibrous histiocytoma (MFH): a complex malignant soft-tissue tumor

Sarcoma microenvironment cell states and ecosystems are associated with prognosis and predict response to immunotherapy

Characterization of the diverse malignant and stromal cell states that make up soft tissue sarcomas and their correlation with patient outcomes has proven difficult using fixed clinical specimens. Here, we employed EcoTyper, a machine-learning framework, to identify the fundamental cell states and cellular ecosystems that make up sarcomas on a large scale using bulk transcriptomes with clinical annotations. We identified and validated 23 sarcoma-specific, transcriptionally defined cell states, many of which were highly prognostic of patient outcomes across independent datasets. We discovered three conserved cellular communities or ecotypes associated with underlying genomic alterations and distinct clinical outcomes. We show that one ecotype defined by tumor-associated macrophages and epithelial-like malignant cells predicts response to immune-checkpoint inhibition but not chemotherapy and validate our findings in an independent cohort. Our results may enable identification of patients with soft tissue sarcomas who could benefit from immunotherapy and help develop new therapeutic strategies.

Biopsy Techniques for Musculoskeletal Tumors: Basic Principles and Specialized Techniques

Biopsy is a pivotal component in the diagnostic process of bone and soft tissue tumors. The objective is to obtain adequate tissue without compromising local tumor dissemination and the patient's survival. This review explores contemporary principles and practices in musculoskeletal biopsies, emphasizing the critical role of diagnostic accuracy while also delving into the evolving landscape of liquid biopsies as a promising alternative in the field. A thorough literature search was done in PubMed and Google Scholar as well as in physical books in libraries to summarize the available biopsy techniques for musculoskeletal tumors, discuss the available methods, risk factors, and complications, and to emphasize the challenges related to biopsies in oncology. Research articles that studied the basic principles and specialized techniques of biopsy techniques in tumor patients were deemed eligible. Their advantages and disadvantages, technical and pathophysiological mechanisms, and possible risks and complications were reviewed, summarized, and discussed. An inadequately executed biopsy may hinder diagnosis and subsequently impact treatment outcomes. All lesions should be approached with a presumption of malignancy until proven otherwise. Liquid biopsies have emerged as a potent non-invasive tool for analyzing tumor phenotype, progression, and drug resistance and guiding treatment decisions in bone sarcomas and metastases. Despite advancements, several barriers remain in biopsies, including challenges related to costs, scalability, reproducibility, and isolation methods. It is paramount that orthopedic oncologists work together with radiologists and pathologists to enhance diagnosis, patient outcomes, and healthcare costs.

Long-term disease-free survival of an undifferentiated pleomorphic sarcoma of the spleen: A case report and literature review

INTRODUCTION

Undifferentiated pleomorphic sarcoma (UPS) primarily occurs in the soft tissues of the extremities, trunk, and retroperitoneum. As the primary UPS of the spleen (splenic UPS) is extremely rare, to the best of our knowledge, only 19 cases have been reported in English literature. No cases of long-term survival without a local or distant recurrence have been reported.

PATIENT CONCERNS

We report the case of a 37-year-old man who was referred to our hospital for a splenic tumor. He had no past medical or relevant familial history. On abdominal computed tomography (CT), a low attenuation solid mass and cystic component with mural calcifications were present at the lower pole of his spleen. The fluorodeoxyglucose-positron emission tomography (CT) indicated it as malignant tumor of the spleen.

DIAGNOSES

The patient's provisional diagnosis was deduced to be angiosarcoma, which was the most common malignant tumor of the spleen.

INTERVENTIONS

An elective laparoscopic splenectomy was performed, and the histology of the tumor was consistent with UPS (pT1, pN0, cM0, and AJCC8th). No adjuvant therapy was administered.

OUTCOMES

Ten years have passed since the patient's splenectomy, and he continues to do well, without evidence of local or distant recurrence.

LESSONS

To the best of our knowledge, this is the first case of long-term recurrence-free survival after surgical management of a splenic UPS. It is probable that radical splenectomy during the disease played the most important role in the patient's long-term survival. Understanding the characteristic findings of a splenic UPS in an abdominal CT may help to diagnose properly.

Pleomorphic spindle cell sarcoma (PSCS) (formerly known as malignant fibrous histiocytoma, MFH) of the spleen, mimics an atypical haemangioma on 99mTc-RBC, CT and Ultrasound: staging with 18F-FDG PET/CT

A 63-year-old male was found to have a 7.5-cm splenic mass that had imaging appearances of an atypical haemangioma on CT, ultrasound and a ^99mTc-RBC scan, and he was followed conservatively with serial ultrasounds. Sixteen months later, however, the splenic lesion grew and he developed numerous new liver masses which were biopsy confirmed to be a pleomorphic spindle cell sarcoma (PSCS), formerly known as malignant fibrous histiocytoma (MFH). A staging ¹⁸F-FDG PET/CT was performed and showed innumerable, mostly necrotic hepatic and splenic masses. The patient passed away a few days after the PET/CT, before a treatment program could be implemented. The use of ¹⁸F-FDG PET/CT in the staging of splenic PSCS has not been previously described. We present the ^99mTc-RBC and ¹⁸F-FDG PET/CT image characteristics of a patient with splenic PSCS.

Abdominal and pelvic tumors with musculoskeletal histology

This article is a case-based review of the broad spectrum of tumors with musculoskeletal histology that can arise in the abdomen or pelvis and involve the soft tissues, muscle, and bone. In this article, pathology-proven cases are presented with a focus on radiographic, computed tomography, magnetic resonance imaging, and positron emission tomography-computed tomography findings. The imaging features that differentiate tumors with musculoskeletal histology from more common abdominal tumors are discussed. Representative cases include malignant fibrous histiocytoma, chondrosarcoma, Ewing sarcoma, hemangiopericytoma, desmoplastic fibroma, neurofibrosarcoma, osteosarcoma, intimal sarcoma, liposarcoma, leiomyosarcoma, synovial sarcoma, teratoma, and chordoma. A variety of tumors with musculoskeletal histology can arise in the abdomen and pelvis. In some cases, unique imaging characteristics allow a confident diagnosis, whereas other cases have a more nonspecific appearance. Recognition of imaging features that suggest a musculoskeletal tumor including direct extension from a bone or neural foramen, the presence of cartilaginous or osseous matrix, or macroscopic fat would allow the radiologist to suggest the proper diagnosis. Recognizing imaging characteristics of tumors with musculoskeletal histology is important clinically as management and prognosis differ from that of more common abdominal tumors.

Current concepts in the biopsy of musculoskeletal tumors

In the management of bone and soft tissue tumors, accurate diagnosis, using a combination of clinical, radiographic, and histological data, is critical to optimize outcome. On occasion, diagnosis can be made by careful history, physical examination, and images alone. However, the ultimate diagnosis usually depends on histologic analysis by an experienced pathologist. Biopsy is a very important and complex surgery in the staging process. It must be done carefully, so as not to adversely affect the outcome. Technical considerations include proper location and orientation of the biopsy incision and meticulous hemostasis. It is necessary to obtain tissue for a histological diagnosis without spreading the tumor and so compromise the treatment. Furthermore, the surgeon does not open compartmental barriers, anatomic planes, joint space, and tissue area around neurovascular bundles. Nevertheless, avoid producing a hematoma. Biopsy should be carefully planned according to the site and definitive surgery and should be performed by an orthopedic surgeon with an experience in musculoskeletal oncology who will perform the definitive surgery. Improperly done, it can complicate patient care and sometimes even eliminate treatment options. Different biopsy techniques are suitable: fine-needle aspiration, core-needle biopsy, and incisional biopsy. The choice of biopsy depends on the size, the location of the lesion, and the experience of the pathologist.