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

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.

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.

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.

Low-Grade Myofibroblastic Sarcoma on Back with Repeated Localized Recurrence and Regional Metastasis

Low-grade myofibroblastic sarcoma (LGMS) is a rare spindle cell tumor with indolent course. Due to rarity and low-grade histologic features of LGMS, accurate diagnosis is challenging. We report a 63-year-old female patient with a three-month history of a 3.1 cm×2.5 cm sized, firm, skin-colored, painless, protruding left back mass. Initial excisional biopsy was performed and the mass was diagnosed as nodular fasciitis. After 18 months after excision, the mass recurred with pain and grew larger. Considering the clinical manifestations, diagnostic impression was changed as dermatofibrosarcoma protuberans not nodular fasciitis. Second wide excision was performed and the histopathology revealed proliferative atypical spindle cells with moderate nuclear atypia and a distinctive whorling pattern, which is suggestive of low-grade sarcoma. Additional computed tomography and positron emission tomography revealed no metastasis and suspicious residual viable malignant tissue. To remove suspicious residual tumor, third wide excision were performed and the diagnosis confirmed as LGMS. A microscopically clear resection was achieved with deep and lateral safety margin 0.6 cm each. Despite of postoperative radiotherapy with 35 times, recurrence of the tumor and lung metastasis was found after 7 months later. LGMS rarely metastasizes and occurs most commonly in the head and neck region. Thus, we report a rare case of LGMS on back which repeated localized recurrence and regional lung metastasis occurred despite wide excision and adjuvant radiotherapy.

Risk Factors for Recurrence and the Role of Radiotherapy in Low-grade Myofibroblastic Sarcoma: A Systematic Review

Low-grade myofibroblastic sarcoma (LGMS) is a rare malignancy that commonly occurs in the head and neck region. The role of radiotherapy has been unclear in treating LGMS and the risk factors for recurrence have remained undefined. The objective of this study is to determine risk factors for the recurrence of LGMS in the head and neck as well as the role of radiotherapy in the treatment of LGMS. A comprehensive review of the literature was performed through Pubmed leading to the inclusion of 36 articles after our inclusion and exclusion criteria were applied. Continuous variables were analyzed with a 2-tail unpaired t test. Categorical variables were assessed with the χ 2 test or Fisher exact test. Logistic regression and multivariable logistic regression analysis with 95% CIs were used to obtain odds ratios. LGMS most commonly occurred in the oral cavity (49.2%). Half of all recurrences occurred in the paranasal sinuses/skull base. LGMS occurring at the paranasal sinuses/skull base had a significantly increased risk of recurrence compared with other subsites within the head and neck (odds ratio: -40; 95% CI: 2.190, 762.005; P = 0.013). The average time to recurrence of LGMS was 19.2 months. Adjuvant treatment with radiation did not improve recurrence rates. Sex, tumor size, or bony involvement were not found as risk factors for recurrence. Patients with LGMS of the paranasal sinuses and skull base are at high risk for recurrence and should be monitored closely. The role of adjuvant radiation treatment in these patients remains unclear.

Clinical Outcome of Low-Grade Myofibroblastic Sarcoma in Japan: A Multicenter Study from the Japanese Musculoskeletal Oncology Group

This retrospective multicenter study aimed to analyze the clinical features and prognosis of 24 patients diagnosed with LGMS between 2002 and 2019 in the Japanese sarcoma network. Twenty-two cases were surgically treated and two cases were treated with radical radiotherapy (RT). The pathological margin was R0 in 14 cases, R1 in 7 cases, and R2 in 1 case. The best overall response in the two patients who underwent radical RT was one complete response and one partial response. Local relapse occurred in 20.8% of patients. Local relapse-free survival (LRFS) was 91.3% at 2 years and 75.4% at 5 years. In univariate analysis, tumors of 5 cm or more were significantly more likely to cause local relapse (p < 0.01). In terms of the treatment of relapsed tumors, surgery was performed in two cases and radical RT was performed in three cases. None of the patients experienced a second local relapse. Disease-specific survival was 100% at 5 years. A wide excision aimed at the microscopically R0 margin is considered the standard treatment for LGMS. However, RT may be a viable option in unresectable cases or in cases where surgery is expected to cause significant functional impairment.

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.

Low-grade myofibroblastic sarcoma of the proximal femur: A case report and literature review

RATIONAL

Low-grade myofibroblastic sarcoma (LGMS) is an atypical type of tumor composed of myofibroblasts. LGMS in the femoral head neck junction is extremely rare and no case treated by hip arthroscopy was reported.

PATIENT CONCERNS

We reported a case of LGMS in the femoral head neck junction treated by hip arthroscopy. A 30-year-old female was admitted to our hospital with discomfort and pain after left hip sprained one year prior. Physical examination revealed swelling of the left hip and magnetic resonance images showed a soft tissue mass in the femoral head neck junction.

DIAGNOSIS

Via microscopy of pathological specimens, spindle cell proliferative lesions, atypia of some cells, and mitotic figures/pathological mitotic figures of some cells were observed. Immunohistochemistry revealed positive for smooth muscle actin, focally positive for CD34 and CD68, while negative for S-100, desmin, and anaplastic lymphoma kinase. The imaging, histomorphological and immunohistochemical features suggested a final diagnosis of LGMS of the proximal femur.

INTERVENTIONS

This patient underwent hip arthroscopy for excision of the soft tissue mass.

OUTCOMES

The clinical and imaging follow-up at 6 months postoperatively showed that surgery had achieved good clinical outcomes.

LESSONS

To the best of our knowledge, this is the first case report of LGMS in the femoral head neck junction treated by hip arthroscopy. Beyond the present case, other 120 cases from 58 literatures (1998-2022) are reviewed and discussed. The age of LGMS patients ranged from 11 months to 77 years and the male-to-female ratio was approximately 1.28:1. The location distribution of previously reported LGMS cases and the present case was as follows: Head&neck (45.90%), trunk (30.33%), and extremity (23.77%). Hip arthroscopic excision of LGMS may achieve relatively good clinical outcomes.

Effective Treatment of Low-Grade Myofibroblastic Sarcoma with Apatinib: A Case Report and Literature Review

Low-grade myofibroblastic sarcoma (LGMS) is a rare, poorly differentiated, malignant tumor. The disease mainly occurs in the head and neck and rarely metastasizes at any age. Currently, there is no consensus regarding the treatment of metastatic LGMS. Here, we report the case of a 45-year-old man who was admitted to our hospital with cough for two weeks and abdominal pain for one week. Preoperative computed tomography revealed a large mass (116×35 mm) in both the lungs and jejunal mass (maximum diameter, 32 mm). The tumor was excised, and immunohistochemical staining was positive for SMA and CD117 and negative for desmin and CD34, indicating a case of LGMS. The patient was effectively treated with apatinib (250 mg/day) after failure of imatinib, liposomal doxorubicin, and ifosfamide. The progression-free survival time was 8.5 months, and the overall survival time was 17 months after treatment with apatinib. No grade 3 or 4 side effects were observed, except hand-foot syndrome. Whole-exome sequencing (WES) and RNA sequencing (RNA-seq) were performed on the patient’s jejunal tumor and para-cancerous tissue samples, and bioinformatics analysis was performed on the results. WES identified five mutations in MKI67, OR2J2, EPPK1, FCGBP, and OR10G4. RNA-seq revealed that 1422 genes were upregulated and 1890 genes were downregulated. The differentially expressed genes were mainly enriched in the phosphatidylinositol 3-kinase (PI3K) signaling pathway, neuroactive ligand-receptor interaction signaling pathway, and cAMP signaling pathway. Our study indicated that apatinib may be a potential novel and effective treatment for LGMS.