Low-grade Myofibroblastic sarcoma: clinical and imaging findings

Enhanced magnetic resonance imaging features and management principles of low-grade myofibroblastic sarcoma of the breast: a case report

Background

Low-grade myofibroblastic sarcoma (LGMS) originating from breast is rare. Existing literature comprises clinical and pathological reports, with limited information on imaging characteristics. This study reports a case of LGMS of the breast and presents its imaging characteristics, with an emphasis on those observed using contrast-enhanced magnetic resonance imaging (MRI).

Case Description

A 50-year-old patient presented with a left breast mass for 1 year. One year before the presentation, the patient had palpated a mass of approximately 1.5 cm in size in the upper part of the left breast without any obvious cause. The mass was perceived to be growing slowly. There was no relevant family history of breast conditions. Physical examination revealed a hard, ill-defined, irregularly shaped, non-tender mass of approximately 3.5 cm × 3 cm in size, with poor mobility and a close connection to the deep skin. The mammography showed a high-density mass without microcalcifications and boundary wrapping. Ultrasonography showed an oval, ill-defined hypoechoic mass. The combination of mammography and ultrasound examination results ruled out the possibility of ductal carcinoma and benign fibroepithelial tumor. On contrast-enhanced MRI, the mass exhibited heterogeneous enhancement, high signal intensity on T2-weighted imaging (T2WI), high signal intensity on diffusion-weighted imaging (DWI), and a type I time-intensity curve (TIC). A core needle biopsy (CNB) suggested a spindle cell tumor. To confirm the diagnosis, the patient underwent surgical excision, and postoperative pathology confirmed LGMS of the breast. The patient subsequently received adjuvant radiotherapy. Seven months postoperatively, bone scintigraphy suggested possible metastases.

Conclusions

LGMS of the breast exhibited a degree of malignancy on ultrasonography, mammography, and MRI, with the contrast-enhanced MRI showing a persistent enhancement pattern (type I TIC). A preoperative biopsy indicated a spindle cell tumor. Surgical excision remains the best diagnostic method. A thorough understanding of the imaging characteristics and biopsy results of this tumor type provides comprehensive information for formulating corresponding treatment plans.

Low-Grade Myofibroblastic Sarcoma of the Acetabulum - A Rare Case with Review of Literature

Introduction

Low-grade myofibroblastic sarcoma (LGMS) is an atypical and extremely infrequent type of tumor, primary mass being usually present in subcutaneous and soft tissue. Bony involvement is very rare. It has a very high chance of recurrence locally due to its aggressive biological behavior, metastasis in other parts of body is rarely seen. On X-ray, it is visualized as an osteolytic and destructive mass. On magnetic resonance imaging (MRI) this tumor shows heterogenous high signal intensity in T2 images and hypo- to iso-intensity in T1 images. Histologically, these tumors present as diffuse, infiltrative growth pattern traversing between muscle fibers, and cellular atypia with singular mitotic figures. These are obligatory criteria for diagnosis. Due to diagnostic difficulty including histopathological limiting factors, the treatment protocol for LGMS s is still challenging.

Case Report

A 21-year-old female with pain in right pelvic and hip region since past 6 months presented with a diffuse swelling over her right hip, along with tenderness over greater trochanter, groin and buttock region. On basis of MRI findings, core needle biopsy was performed for diagnosis and the sample was suggestive of a spindle cell lesion composed of cells arranged in haphazard and vaguely fascicular pattern. To confirm the diagnosis immunohistochemistry marker study was done, revealing features suggestive of LGMS (smooth muscle actin: Positive, B-cell lymphoma 2: Positive.

Desmin

Negative, H-caldesmon: Negative). Histomorphological and immune-histo-chemical features showed a final diagnosis of LGMS of right-sided acetabulum. Positron emission tomography -scan was done to rule out any distant metastasis, and it did not show any definitive evidence of abnormal hyper-metabolism elsewhere in the body. Pre-operative computed tomography (CT) angiography was done and plan was made to embolize the feeding vessels preoperatively using the findings of CT angiography.

Conclusion

Presentation of LGMS with bone involvement or bone lesions is very rare. Clinicoradiological diagnosis be misinterpreted as a benign lesion which can lead to insufficient resection and local recurrence of the tumor. For treatment in such cases, most studies emphasize on excision of tumor with a wide surgical margin, but regarding the safety distance for better adequacy, relevant data is still inconsistent. In our case, we have reported a case of a 21-year-old female for gross total resection and reconstruction of an acetabular LGMS with extension into iliac wing. To the best of our knowledge, it is the first case of this tumor involving the acetabulum.

Multiple Bone Involvement in Low-grade Myofibroblastic Sarcoma Demonstrated on 18F-FDG PET/CT

A 68-year-old woman with low back pain for 2 months was admitted. T2-weighted fat-saturated imaging revealed hyperintense lesions in multiple lumbar regions, suggesting the possibility of bone metastases. Multiple osteolytic and mixed osteolytic-osteoblastic lesions with significant 18F-fluorodeoxyglucose (18F-FDG) uptake, as well as multiple osteoblastic lesions with mild 18F-FDG uptake, were observed on subsequent 18F-FDG positron emission tomography/computed tomography without an identifiable primary lesion. This patient was pathologically diagnosed with low-grade myofibroblastic sarcoma (LGMS) after biopsy and surgery. Although multiple bone involvement in LGMS is extremely rare, this case suggests that it should be considered in the differential diagnosis of multiple bone metastases.

Huge intermediate-grade myofibroblastic sarcoma in the retroperitoneum revealed by 18F-FDG PET/CT: a case report

Myofibroblastic sarcoma (MS) is a relatively rare malignant bone and soft tissue tumor, which originates from myofibroblasts, with some characteristics of both smooth muscle cells and fibroblasts. It can develop in individuals at any age and can affect various regions, especially the head and neck; however, it is rarely reported retroperitoneally. Generally, this type of sarcoma is considered a low-grade malignancy, and cases classified as moderate and high-grade malignancy are rare. In this study, we describe a case of intermediate-grade myofibroblastic sarcoma (IGMS) originating from the retroperitoneum, which was confirmed through pathological diagnosis. The 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) scan revealed a large, borderless mass located retroperitoneally with a significantly increased 18F-FDG uptake, accompanied by adjacent visceral and soft tissue infiltration and peripheral lymph node metastasis. The patient received chemotherapy for 3 weeks; however, the tumor did not shrink significantly. Therefore, the patient discontinued the treatment. After 5 months, his condition gradually deteriorated, which eventually led to death. Through this case report, the diagnosis and treatment of moderate malignant retroperitoneal myofibroblastoma were discussed, aiming to increase clinicians' understanding of this disease.

Myofibroblastic sarcoma in breast: a case report and literature review

Myofibroblastic sarcoma is a malignancy in which myofibroblasts are the main component, with a very low incidence. In this study, we report a case of low-grade myofibroblastic sarcoma (LGMS) in the breast. After the diagnosis of LGMS, the patient received a mastectomy. The patient showed no relapse or progression during the follow-up time of 3 months following the operation. LGMS in the breast is extremely rare, and the limited experience with its diagnosis and treatment brings obstacles to doctors. Therefore, this report summarizes the preoperative diagnosis, treatment, and prognosis of breast LGMS through a literature review.

Indolent growth of low‑grade myofibroblastic sarcoma of the knee with the resemblance of a benign lesion: A case report

Low-grade myofibroblastic sarcoma (LGMS) is a rare soft-tissue malignant neoplasm originating from the stromal cells that is predominantly comprised of atypical myofibroblasts. The present study reports the case of a patient with low-grade myofibroblastic sarcoma in the soft tissue of the knee. The patient exhibited a soft, painless mass on the medial side of the left knee. During surgery, a yellow-white mass above the posterior margin of the sartorius muscle was identified. This mass, which was irregular and adherent to surrounding tissues, had a blurry boundary, indicative of invasive growth. The morphology of the mass significantly differed from conventional lipomas and was lacking typical features. Immunohistochemical staining confirmed the diagnosis of a malignant LGMS. The patient experienced no recurrence over 1 year of follow-up and reported complete recovery of knee range of motion. The present study suggests that an incisional biopsy may be performed if LGMS is suspected based on patient symptoms and imaging results. In addition, long-term follow-up is crucial for the timely detection and management of any recurrence, playing a key role in the patient's ongoing care and treatment.

Anlotinib in combination with pembrolizumab for low-grade myofibroblastic sarcoma of the pancreas: A case report

BACKGROUND

Low-grade myofibroblastic sarcoma (LGMS) is a rare spindle cell sarcoma especially in the pancreas, with myofibroblastic differentiation. Hitherto, only a few cases have been reported.

CASE SUMMARY

Herein, we report a case involving the discovery of a pancreatic mass detected during a routine physical examination. Subsequent imaging and pathological tests of the patient led to the diagnosis of LGMS of the pancreas. Following surgical intervention, the patient experienced recurrence and metastasis. Conventional treatment is not effective for postoperative recurrent pancreatic LGMS with multiple metastases. After communicating with the patients and their families, informed consent was obtained for the treatment of anlotinib combined with pembrolizumab. Evaluation of imaging and clinical symptoms post-treatment revealed a relatively favorable response to the combination of anlotinib and pembrolizumab.

CONCLUSION

Based on the comprehensive literature review, our report aimed to provide evidence for a better understanding of the disease characteristics, diagnostic criteria, imaging findings, and identification of LGMS. And explore novel treatment strategies for this disease.

A Systematic Review and Illustrative Case Presentation of Low-Grade Myofibroblastic Sarcoma (LGMS) of the Extremities

INTRODUCTION

Low-grade myofibroblastic sarcoma (LGMS) is a rare tumor entity which occurs in the subcutaneous and deep soft tissues; it is less common in the bone with a predilection for the extremities and the head and neck region. As confirming the diagnosis is difficult and treatment strategies are not standardized, we aimed to identify patient and tumor characteristics, and to summarize treatment strategies and their clinical outcomes to guide surgeons.

METHODS

Included were full articles reporting patients with histology of LGMS in the extremities, excluding tumors of the trunk. All patients underwent surgery but with different extend, from marginal to wide resection. Included studies should inform about local recurrence, metastasis, or evidence of disease, depending on the surgical treatment. We conducted a structured search using MEDLINE (via PubMed), Web of Science, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) to identify studies on low-grade myofibroblastic sarcoma of the extremities. Study designs like randomized controlled trials, systematic reviews, prospective trials, retrospective studies, and case reports were included. Prospective studies and comparative studies were not available at all. Therefore, meta-analysis was not possible and statistical analysis was purely descriptive.

RESULTS

Of the 789 studies identified from our initial search, 17 studies including 59 cases reported LGMS of the extremities with the surgical treatment and clinical outcome and were therefore analyzed. In addition, we present the rare case and surgical management of a 28-year-old male patient with residual LGMS of the thumb after an initial incomplete resection. The current literature suggests that a wide excision with R0 margins should be considered the standard treatment for LGMS. In cases where surgery leads to significant functional impairment, individual options like free tissue transfer from a donor site have to be considered. Therefore, we also present an illustrative case. For all selected case series and case reports, a high risk of confounding, selection bias, information bias, and reporting bias must be anticipated. Nevertheless, this systematic review provides a comprehensive overview on surgical treatment and clinical outcomes in LGMS surgery of the extremities.

Small biopsies in the head and neck: Bone and soft tissue

Bone and soft tissue lesions in the head and neck encompass not only a broad morphologic spectrum but also significant inherent clinicopathologic overlap. Epidemiology, radiology, and location - similar to the diagnostic assessment in other sites - are especially important considerations in the context of an established mesenchymal proliferation. Herein, the approach towards diagnosis is stratified by morphology (spindle, sarcomatoid, epithelioid, round cell), cellular lineage (fibroblastic, nerve sheath, rhabdomyogenic), and tumor grade (benign, low- to high-grade malignant) as the basis of further immunohistochemical or molecular investigation.

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.

A Radiation Induced Low-Grade Myofibroblastic Sarcoma in the Retropectoral Area After Breast Conserving Surgery: A Case Report

Low-grade myofibroblastic sarcoma (LGMFS) is a rare type of sarcoma, and its manifestation as a radiotherapy (RT)-induced sarcoma following RT for breast cancer is even more unusual. To date, only one case of RT-induced mammary myofibroblastic sarcoma (MFS) has been reported. Here we present the case of a 49-year-old woman with LGMFS after undergoing breast-conserving surgery for invasive ductal carcinoma (IDC), and with a history of RT 16 years prior. Due to the rarity of this disease, previous studies have focused primarily on the pathological findings of MFS. In this report however, we present the clinical and radiological features of LGMFS in the retro pectoral area as a rare type of RT-induced sarcoma.

Imaging features of myxoid soft-tissue tumours

Myxoid soft-tissue tumours are mesenchymal neoplasms, which are characterised by the production of abundant extracellular myxoid matrix. Imaging plays an important role in the diagnosis of these tumours as well as treatment planning. The imaging features as well as the clinical course for these lesions are highly variable, depending on both the anatomical location of the tumour and the histopathological subtype. This article, illustrated by histopathologically proven cases from our tertiary referral soft-tissue sarcoma centre, reviews the spectrum of imaging findings and characteristic signs seen with different types of benign and malignant myxoid soft-tissue neoplasms.

Case report: Low-grade myofibroblastic sarcoma resembling lymphoma on 18F-FDG PET/CT

Low-grade myofibroblastic sarcoma is a rare malignant tumor that arises from mesenchymal tissue and affects the head (particularly the tongue and oral cavity) and neck. It is characterized by local recurrence, with metastases being uncommon. We present a 72-year-old man who initially complained of a painless and progressive mass in the right inguinal region and came for consultation, and a malignant tumor was suspected based on the clinical and pelvic MRI manifestations. The ¹⁸F-FDG PET/CT revealed that the multiple lesions were located in the mediastinum, retroperitoneum, pelvis, and inguinal lymph nodes; hence, lymphoma was considered to be a combination of the symptoms. However, the histology of the ultrasound-guided puncture indicated low-grade myofibroblastic sarcoma. The patient was next administered chemotherapy, but the lesions did not undergo remission.

A 37-Year-Old Man with Myofibroblast Sarcoma Combined with Pleural Maculopathy: Case Report

Myofibroblastic sarcoma (MS) is a malignant tumor of soft tissue or bone that can occur in children or adults, with a high rate of recurrence and metastasis. We report a case of low-grade malignant MS of the left shoulder, diagnosed based on pathological examination and immunohistochemical staining. However, the patient had unexplained pleural maculopathy. The patient passed away 6 months after the diagnosis of myofibroblast sarcoma due to multiple metastases throughout the sarcoma. Combined with the patient's history, ancillary findings, and after MDT discussion, the patient was ultimately considered to have a high probability of myofibroblast sarcoma combined with pleural maculopathy. In conclusion, when a patient is diagnosed with myofibroblast sarcoma in combination with pleural macula, in the absence of other causative factors, a deep tissue biopsy of the pleura should be actively performed to confirm the diagnosis.

Low-grade myofibroblastic sarcoma of the mandible: A rare tumour of childhood

Low-grade myofibroblastic sarcoma is a rare and indolent tumour of soft tissue. This tumour is relatively common in the head and neck region followed by extremities. Primary low-grade myofibroblastic sarcoma of the mandible is very rarely reported and the occurrence of this tumour in a child is very unusual. A 7-year-old male child presented with a swelling in right angle of mandible. X-ray and computed tomography scan showed a lytic lesion. The lesion was excised and the tissue was sent for histopathological evaluation, which revealed a cellular spindle cell neoplasm arranged in fascicles. The tumour was partly circumscribed and lobulated. On immunohistochemistry (IHC), these tumour cells showed cytoplasmic positivity for vimentin, and smooth muscle actin showed 'tram-track' pattern of positivity. The case was diagnosed as low-grade myofibroblastic sarcoma. There are no definite clinical features or pathognomonic radiological appearances of this tumour that can differentiate this rare tumour from other commonly encountered gnathic bone tumours, such as osteosarcoma, inflammatory myofibroblastic tumour, etc., Histopathological diagnosis coupled with ancillary investigations such as IHC is important to establish a definite diagnosis and rule out the differentials. The exact biological behaviour of this tumour is not known.

Retrospective immunohistochemical investigation of suspected non-visceral leiomyosarcoma in dogs

Visceral leiomyosarcoma is well described in dogs, but information about non-visceral locations and prevalence is lacking. The diagnosis of leiomyosarcoma is challenging without a gold standard, and often includes the use of immunohistochemical (IHC) stains. We used defined histopathologic patterns, histochemical staining, and IHC staining for smooth muscle actin (SMA), desmin, and laminin to characterize suspected non-visceral leiomyosarcoma in dogs at a single academic institution. In a retrospective search, we identified 24 dogs with a definitive or suspected histologic diagnosis of leiomyosarcoma in a non-visceral location. Histopathology results and clinical details were obtained. Biopsy sections were reviewed by a single pathologist using standardized histologic criteria, including light microscopic appearance, immunohistochemistry (more than two-thirds of neoplastic cells labeled with SMA and desmin or laminin), and histochemical staining (minimal-to-mild matrix deposition by Masson trichrome). Of the 24 cases of possible non-visceral leiomyosarcomas, 4 were consistent with a definitive diagnosis of non-visceral leiomyosarcoma (3) or leiomyoma (1) based on the established criteria. Only the leiomyoma had more than two-thirds of neoplastic cells label with all 3 markers; all 3 leiomyosarcomas had more than two-thirds of neoplastic cells label with SMA and laminin. Our data highlight the uncommon nature of non-visceral leiomyosarcoma and the importance of IHC for their diagnosis. A definitive diagnosis could not be made based on SMA alone, and desmin was not useful in this cohort. Further studies are needed to clarify the histopathologic, IHC, and clinical features of canine non-visceral SMA-positive mesenchymal tumors.

Primary Osseous Low-grade Myxofibrosarcoma of Metatarsal Masquerading as Enchondroma: A Case Report

Introduction

Low-grade myxofibrosarcoma (LGMFS) is a neoplasm of soft tissues. According to the World Health Organization, LGMFS is a malignant myofibroblastic tumor arising from deep soft tissues with potential for recurrence and late metastatic spread. The incidence estimates are 0.18/million, accounting for 0.6% of all soft-tissue sarcomas. It can directly invade the bone and metastasize to bone; however, primary osseous low-grade myxofibrosarcoma is a rare entity. Thus, recognizing atypical presentations of uncommon neoplasms are a pertinent skill for the radiologist due to significant implications for management.

Case Report

A 40-year-old male with complaints of midfoot pain was referred to radiology department for imaging. Radiographs of the foot showed a lytic mildly expansile lesion in the first metacarpal with wide zone of transition and no sclerotic margin or matrix calcification. Magnetic resource imaging (MRI) and computed tomography (CT) examination demonstrated well defined lobulated lesion which appeared heterogeneously hyperintense on T2W images with cortical breach, extraosseous soft-tissue component, and early rapid progressive enhancement. The radiological diagnosis of enchondroma with pathological fracture was considered. Atypical findings of early progressive enhancement and extraosseous soft-tissue component were, however, incongruous with enchondroma and possibility of an aggressive/malignant etiology was also considered. Hence, the lesion was biopsied and diagnosis of LGMFS was made and subsequently confirmed on excised specimen. Follow-up CT scan post 6 months of surgical resection demonstrated no recurrence.

Conclusion

Primary osseous LGMFS is a rare entity and radiologically mimics enchondromas. Both LGMFS and enchondromas show T2W hyperintensity. MRI features that distinguish LGMFS from enchondroma include low apparent diffusion coefficient values and slow progressive enhancement in dynamic contrast-enhanced MRI.

Surgical treatment and long-term outcomes of low-grade myofibroblastic sarcoma: a single-center case series of 15 patients

Background

Low-grade myofibroblastic sarcoma (LGMS) is a poorly studied, rare, soft tissue sarcoma. LGMS is characterized by a low malignancy potential, tendency for local recurrence, and low likelihood of distant metastases. However, no studies have reported on the surgical treatment method and its long-term outcomes.

Methods

We included all patients treated for LGMS at our institution between March 2010 and March 2021. Medical charts were retrospectively reviewed to collect demographic information, as well as information about the clinical course, tumor characteristics, and outcomes. Statistical analysis was performed to identify the factors associated with the recurrence rate.

Results

Fifteen patients who underwent surgical treatment were enrolled in this study. There were seven cases in the upper extremities, four in the trunk area, three in the lower extremities, and one in the head and neck area. There were no metastatic cases and two cases of local recurrence.

Conclusions

The incidence of LGMS in the extremities or trunk may be higher than expected based on the current literature. Univariate analysis showed that local tissue invasion and surgical method could be associated with local recurrence. Although further large studies are needed to establish risk factors of local recurrence or extent of resection margins, based on our study, wide local excision under the proper diagnosis is the most important treatment.

Limbal, low-grade myofibroblastic sarcoma: Case report and literature review

Low-grade myofibroblastic sarcoma is a relatively recently-described neoplasm of the myofibroblasts having a predilection for the head and neck region. Ophthalmic involvement is extremely rare. Limbal involvement has not yet been documented in the literature. We describe one such case involving the limbus of a 48-year-old Asian male.

Primary low-grade myofibroblastic sarcoma: A rare case report of this tumor in the orbit and literature review

Low-grade myofibroblastic sarcoma (LGMS) is an exceedingly rare, malignant tumor with myofibroblastic differentiation. It frequently occurs in the oral cavity and extremities, despite being classified as a distinct entity by the World Health Organization (WHO). Here, we report a rare case of orbital LGMS occurring in an 11-month-old baby with a 3.2 × 2.4 × 2.1 cm mass. LGMS was diagnosed based on the histological and immunohistochemical findings. Previous literature suggests that surgical resection with clear margins is an appropriate method for the treatment of LGMS, and combined adjuvant therapy (local radiotherapy with or without chemotherapy) can improve the prognosis, but further studies are needed.