Low-grade myofibroblastic sarcoma of the palate

Oral and Maxillofacial Low-Grade Myofibroblastic Sarcoma: A Systematic Review

BACKGROUND

This systematic review (SR) aimed to summarize the clinical, histopathological, and immunohistochemical features of low-grade myofibroblastic sarcoma (LGMS) in the oral and maxillofacial region (OMR), as well as treatment protocols, recurrence, follow-up, and metastasis rates. It follows PRISMA 2022 guidelines and is registered in PROSPERO (CRD42023409758).

METHODS

An electronic search included PubMed, EMBASE, Scopus, Web of Science, LILACS, Google Scholar, and ProQuest databases, and bias risk was assessed using the Joanna Briggs Institute tool. Statistical analyses, including Fisher's and Chi-Squared tests, were conducted to explore associations between clinical variables, and survival analysis was performed using the Kaplan-Meier method.

RESULTS

Forty-three studies covering 78 cases were included. LGMS showed a slight female predominance (51.28%) and an average patient age of 35.35 years. The most affected sites were the mandible (29.4%), maxilla (19.23%), and tongue (15.38%). Clinical presentations included masses (30.76%), tumors (26.92%), and swelling (12.82%), with symptom duration ranging from 1 week to 30 months. Surgery alone was the primary treatment (60.25%), with recurrence in 20.51% and metastasis in 5.12% of cases. One-year and 5-year overall survival rates were 92.6% and 71.8%, respectively. Surgery as the sole treatment was significantly associated with a lower metastasis rate (p = 0.005).

CONCLUSION

Our findings highlighted the importance of considering LGMS in differential diagnoses of myofibroblastic lesions and underscored the need for a comprehensive immunohistochemical analysis. Complete surgical excision remains the preferred treatment, though long-term follow-up is needed to better understand recurrence and metastasis risks.

Low-Grade Myofibroblastic Sarcoma of Hard Palate-A Diagnostic Challenge with Review of Literature

Low-grade myofibroblastic sarcoma (LGMS) is categorized as an extremely rare malignant neoplasia of myofibroblasts. To date, only 38 cases describing patients diagnosed with LGMS in the oro-maxillofacial region have been reported in the scientific literature. Here, we introduce a rare case report and, for the first time, also provide a recent update of the literature and a clear review regarding the immunohistochemical panel to diagnose this entity.

Low-grade myofibrosarcoma of the maxillary sinus: Two case reports

BACKGROUND

Low-grade myofibroblastic sarcoma (LGMS) is an extremely rare tumor characterized by the malignant proliferation of myofibroblasts. LGMS most commonly develops in adults, predominantly in males, in the head and neck region, oral cavity, especially on the tongue, mandible, and larynx. This article presents 2 cases of LGMS localized to the maxillary sinus and provides an overview of the available literature.

CASE SUMMARY

Two patients with LGMS located in the maxillary sinus underwent surgery at the Department of Head and Neck Surgery. Case 1: A 46-year-old patient was admitted to the clinic with suspected LGMS recurrence in the right maxillary sinus (rT4aN0M0), with symptoms of pain in the suborbital area, watering of the right eye, thick discharge from the right nostril, and augmented facial asymmetry. After open biopsy-confirmed LGMS, the patient underwent expanded maxillectomy of the right side with immediate palate reconstruction using a microvascular skin flap harvested surgically from the middle arm. The patient qualified for adjuvant radiotherapy for the postoperative bed, with an additional margin. Currently, the patient is under 1.5 years of observation with no evidence of disease. Case 2: A 45-year-old man was admitted to our clinic with facial asymmetry, strabismus, exophthalmos, and visual impairment in the right eye. Six months earlier, the patient had undergone partial jaw resection at another hospital for fibromatosis. A contrast-enhanced computed tomography scan revealed a tumor mass in the postoperative log after an earlier procedure. An open biopsy confirmed low-grade fibrosarcoma (rT4aN0M0). The patient qualified for an extended total right maxillectomy with orbital excision and right hemimandibulectomy with immediate microvascular reconstruction using an anterolateral thigh flap. The patient subsequently underwent adjuvant radiotherapy to the postoperative area. After 9 months, recurrence occurred in the right mandibular arch below the irradiated area. The lesion infiltrated the base of the skull, which warranted the withdrawal of radiotherapy and salvage surgery. The patient qualified for palliative chemotherapy with a regimen of doxorubicin + dacarbazine + cyclophosphamide and palliative radiotherapy for bone metastases. The patient died 26 months after surgical treatment. The cases have been assessed and compared with cases in the literature.

CONCLUSION

No specific diagnostic criteria or treatment strategies have been developed for LGMS. The treatment used for LGMS is the same as that used for sinonasal cancer radical tumor excision; adjuvant radiotherapy or chemoradiotherapy should also be considered. They have low malignant potential but are highly invasive, tend to recur, and metastasize to distant sites. Patients should undergo regular follow-up examinations to detect recurrence or metastasis at an early stage. Patients should be treated and observed at the highest referral centers.

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.

Low-Grade Myofibroblastic Sarcoma of the Oral and Maxillofacial Region: An International Clinicopathologic Study of 13 Cases and Literature Review

Low-grade myofibroblastic sarcoma (LGMS) represents an atypical tumor composed of myofibroblasts with a variety of histological patterns and with a high tendency to local recurrence and a low probability of distant metastases. LGMS has predilection for the head and neck regions, especially the oral cavity. This study aimed to report 13 new cases of LGMS arising in the oral and maxillofacial region. This study included LGMS cases from five oral and maxillofacial pathology laboratories in four different countries (Brazil, Peru, Guatemala, and South Africa). Their clinical, radiographic, histopathological, and immunohistochemical findings were evaluated. In this current international case series, most patients were females with a mean age of 38.7 years, and commonly presenting a nodular lesion in maxilla. Microscopically, all cases showed a neoplasm formed by oval to spindle cells in a fibrous stroma with myxoid and dense areas, some atypical mitoses, and prominent nucleoli. The immunohistochemical panel showed positivity for smooth muscle actin (12 of 13 cases), HHF35 (2 of 4 cases), β-catenin (3 of 5 cases), desmin (3 of 11 cases), and Ki-67 (range from 5 to 50%). H-caldesmon was negative for all cases. The diagnosis of LGMS was confirmed in all cases. LGMS shows predominance in young adults, with a slight predilection for the female sex, and maxillary region. LGMS should be a differential diagnosis of myofibroblastic lesions that show a proliferation of spindle cells in a fibrous stroma with myxoid and dense areas and some atypical mitoses, supporting the diagnosis with a complementary immunohistochemical study. Complete surgical excision with clear margins is the treatment of choice. However, long-term follow-up information is required before definitive conclusions can be drawn regarding the incidence of recurrence and the possibility of metastasis.

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.

Case Report: Immunotherapy for low-grade myofibroblastic sarcoma of the pharynx

Low-grade myofibroblastic sarcoma (LGMS) characterized by the increased proliferation of myofibroblasts is a rare type of malignant myofibroblastic tumor that frequently occurs in the head and neck region. Presently, there is no consensus regarding the treatment of LGMS. Here, we report a rare case of LGMS of the pharynx in a 40-year-old male admitted to our hospital. The patient underwent resection for a right metastatic lesion and parapharyngeal mass. However, he had recurrence and multiple metastases without a surgical indication. Then the patient received the treatment of anlotinib plus pembrolizumab for 4 cycles, and there was a partial response (PR) to the treatment. Due to the adverse reaction of anlotinib, the patient subsequently received monotherapy of pembrolizumab for 22 cycles and achieved a complete response (CR). As the first case report of the immunotherapy for LGMS, our study highlights that this strategy may be of great significance to the treatment of LGMS.

An update on selected cutaneous (myo) fibroblastic mesenchymal tumors

Cutaneous (myo)fibroblastic tumors constitute a group of tumors with overlapping clinicopathological features and variable biologic behavior. In the present review we focus on the histomorphology, immunohistochemical profile and molecular background of the following entities: dermatofibrosarcoma protuberans (DFSP), CD34-positive fibroblastic tumor (SCD34FT), myxoinflammatory sarcoma (MIFS), low-grade myofibroblastic sarcoma, solitary fibrous tumor and nodular fasciitis. Although some of these entities typically arise in deep-seated locations, they may occasionally present as cutaneous/superficial tumors and might be challenging to recognize. This review covers in depth the latest advances in molecular diagnostics and immunohistochemical markers that have significantly facilitated the correct classification and diagnosis of these neoplasms.

Recurrent Giant Myofibroblastic Sarcoma of Neck in a Teenager: Overcoming Treatment Challenges

Sarcomas are rare tumors arising from a variety of mesenchymal tissues which are even rarer in head and neck region amounting 1% only of the 5% of sarcomas. About 80% of head and neck sarcomas originate in soft tissue while the remaining 20% arise from bone (Cormier and Pollock in J Clin 54:94-109, 2004). One among the commonly presenting variants of sarcomas in head and neck that our patient was diagnosed with is Low grade myofibroblastic sarcoma (LGMS). These even though uncommon have a predilection for head and neck region particularly the tongue (Mentzel et al. in Am J Surg Pathol 22:1228-38, 1998; Cai et al. in Virchows Arch 463:827-36, 2013; Meng et al. in Chin Med J 120:363-9, 2007; Demarosi et al. in Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 108:248-54, 2009). LGMS was reclassified as a distinct entity by the WHO classification of soft tissue tumors in 2002 (Qiu et al. in Oncol Lett 9:619-25, 2015). Oncological resection is the mainstay of treatment. In case of bulky tumor, resection and reconstruction would be challenging. We report a recurrent LGMS of 15-year-old girl who presented with a ginormous soft tissue swelling in her left neck region which made her day-to-day activities strenuous and made her non ambulatory and the line of treatment executed in order to get her back on feet, healthy & free of the debilitating tumor.

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.

A rare low-grade myofibroblastic sarcoma in lower jaw with the resemblance to benign lesions

Background

Low-grade myofibroblastic sarcoma (LGMS) is a rare solid infiltrative soft tissue tumor with a predilection for the head and neck region.

Case presentation

We report the diagnostic steps of a fast-growing lesion of the lower left jaw in a 45-year-old otherwise healthy woman. A first biopsy and subsequent histopathological examination showed potential differentials of a benign myofibroma, benign nodular fasciitis or an LGMS. This diagnostic overlap was a challenge for the decision of the further treatment approach. The treatment consisted of a segmental en bloc resection of the mandible including the second premolar, first and second molar. Histopathological examination of the resected tumor confirmed an LGMS.

Conclusion

The histopathologic resemblance of LGMS to a range of benign and reactive tumors may lead to misdiagnosis and mistreatment. The rarity of LGMS explains the lack of established treatment protocols. This case shows the importance of adequate clinical decisions, expertise in the histopathology of rare tumors and interdisciplinary exchange to achieve state-of-the-art patient management.

Recent Application of Artificial Intelligence in Non-Gynecological Cancer Cytopathology: A Systematic Review

State-of-the-art artificial intelligence (AI) has recently gained considerable interest in the healthcare sector and has provided solutions to problems through automated diagnosis. Cytological examination is a crucial step in the initial diagnosis of cancer, although it shows limited diagnostic efficacy. Recently, AI applications in the processing of cytopathological images have shown promising results despite the elementary level of the technology. Here, we performed a systematic review with a quantitative analysis of recent AI applications in non-gynecological (non-GYN) cancer cytology to understand the current technical status. We searched the major online databases, including MEDLINE, Cochrane Library, and EMBASE, for relevant English articles published from January 2010 to January 2021. The searched query terms were: "artificial intelligence", "image processing", "deep learning", "cytopathology", and "fine-needle aspiration cytology." Out of 17,000 studies, only 26 studies (26 models) were included in the full-text review, whereas 13 studies were included for quantitative analysis. There were eight classes of AI models treated of according to target organs: thyroid (n = 11, 39%), urinary bladder (n = 6, 21%), lung (n = 4, 14%), breast (n = 2, 7%), pleural effusion (n = 2, 7%), ovary (n = 1, 4%), pancreas (n = 1, 4%), and prostate (n = 1, 4). Most of the studies focused on classification and segmentation tasks. Although most of the studies showed impressive results, the sizes of the training and validation datasets were limited. Overall, AI is also promising for non-GYN cancer cytopathology analysis, such as pathology or gynecological cytology. However, the lack of well-annotated, large-scale datasets with Z-stacking and external cross-validation was the major limitation found across all studies. Future studies with larger datasets with high-quality annotations and external validation are required.

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.

Sarcomas of the Larynx: One Institution's Experience and Treatment Protocol Analyses

Soft tissue sarcomas in the head and neck are rare malignancies. They occur in this area in less than 1% of all malignant tumors. Some authors have described the development of sarcoma from the mesenchymal tissue in the larynx. The histological diagnosis of a sarcoma depends on the immunohistochemical investigation. In particularly difficult diagnoses, electron microscopy has to be used. The treatment recommendation depends on the histological type of sarcoma. We analysed and summarized data on the diagnostic criteria and therapy for sarcoma of the larynx presented in the literature. We present three new cases of laryngeal sarcoma and describe the analyses of the published diagnostic and treatment schedules of laryngeal sarcomas. We developed a treatment protocol recommendation for laryngeal sarcoma based on an analysis of literature data and case reports. This recommendation is based on histological type, staging, grading, size, and survival data.

Is there a role for chemotherapy and radiation in the treatment of patients with low-grade myofibroblastic sarcoma?

PURPOSE

Low-grade myofibroblastic sarcoma (LGMS) is a rare entity with a predilection for the head and neck. There are still no optimal treatment strategies for patients with LGMS. We retrospectively investigated the efficacies of chemotherapy and radiation treatment for patients with LGMS.

METHODS/PATIENTS

We obtained data from the Surveillance, Epidemiology, and End Result (SEER) database for 96 patients diagnosed with LGMS between 2001 and 2015. We used Kaplan-Meier curves and log-rank tests to estimate overall survival (OS) and Cox proportional hazard regression to identify prognostic factors.

RESULTS

The median age of the patients was 55.0 years. Twenty-two of the patients had LGMS in the head and neck region. Of the 96 patients, 86 (89.6%) received surgical treatment, 28 (29.2%) received radiation treatment, and 20 (10.4%) received chemotherapy. The mean OS was 125.2 [95% confidence interval (CI) 106.3-144.2] months. The 1, 3, 5, and 10-year OS rates were 88%, 77%, 70%, and 59%, respectively. Age greater than 60 years, positive nodal status, and no surgical treatment were independent prognostic factors for patients with LGMS, whereas chemotherapy and radiation treatment were not.

CONCLUSIONS

Surgical resection is the most effective therapy for LGMS. Chemotherapy and radiation had limited effects on survival improvement for patients with LGMS. Therefore, chemotherapy and/or radiation therapy should not be routinely performed in LGMS, especially for those with negative margins after surgery.

Low-Grade Myofibroblastic Sarcoma of the Oral Cavity: A Report of Three Cases Illustrating an Emerging Disease in Children

Low-grade myofibroblastic sarcoma (LGMS) is a mesenchymal tumor of myofibroblasts that occurs more frequently in adults. A series of three cases is presented to illustrate that LGMS may also occur within the oral cavity in children and adolescents. The first case (Case 1) occurred intra-osseously in the mandible, while the remaining two presented as gingival swellings and were purely restricted to soft tissue (Cases 2 and 3). The intra-osseous lesion arose in a 7-year-old girl, whereas the gingival lesions were observed in a 12-year-old girl (Case 2) and a 13-year-old boy (Case 3). Histopathologically, all cases were composed of spindle shaped cells arranged into long fascicles showing mild to moderate degree of nuclear atypia. Ki-67 (MIB-1) proliferation activity was relatively low, amounting to 3–5% in all cases. Immunohistochemically, all cases showed smooth muscle actin (SMA) positivity in spindle cells, while desmin, beta catenin, cytokeratin, and CD34 were negative, resulting in a diagnosis of LGMS. In conclusion, current series of three cases of LGMSs that occurred in the oral cavity in a child and two adolescent patients is presented to highlight an emerging disease that requires additional data for further characterization.

Low-grade myofibroblastic sarcoma of the levator scapulae muscle: a case report and literature review

BACKGROUND

Low-grade myofibroblastic sarcoma (LGMS) is described as a distinct atypical myofibroblastic tumor often with fibromatosis-like features and predilection for the head and neck, especially the oral cavity and larynx. LGMS arising in the levator scapulae muscle is extremely rare.

CASE PRESENTATION

A 69-year-old woman was admitted to our hospital because she noticed a hard mass in her left neck six months prior. Magnetic resonance images (MRI) showed a soft tissue tumor of the left levator scapulae muscle. A core needle biopsy showed cellular fascicles or a storiform growth pattern of spindle-shaped tumor cells with minimally atypia. Immunohistochemistry revealed focally positive for α-smooth muscle actin (α-SMA), negative for S-100, and a low-grade spindle cell sarcoma was suspected. Following a biopsy, the tumor was resected with a wide surgical margin. Immunohistochemical staining was a positive for vimentin and α-SMA and negative for desmin, CD34, nuclear β-catenin, and h-caldesmon. LGMS diagnosis was determined based on the histopathological findings. The patient was alive with no evidence of disease eight years after the surgery.

CONCLUSIONS

To the best of our knowledge, this is the first case report of LGMS arising in the levator scapulae muscle. In addition to the case report, 48 reports with 103 LGMS cases are reviewed and discussed. In previous reports of LGMS, there were 43 females and 60 males, with a mean age of 43.0 years (range, 2-75). There were 13 (12.6%) patients aged < 18 years, 67 (65.1%) patients aged 18 to 59 years, and 23 (22.3%) patients aged ≥60 years. The average tumor size was 4.4 cm (range: 0.4-22.0). The commonest sites of LGMS was the tongue. Tumor growth patterns were evaluated in 52 cases, and 44 cases (84.6%) showed infiltrative growth patterns. Local recurrence was 26.7%, and distant metastasis was 4.4%. Because of the locally aggressive feature, it is important to diagnose LGMS with biopsy and to excise the tumor with an adequately wide margin.

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.

Low-grade Myofibroblastic sarcoma: clinical and imaging findings

Background

Low-grade myofibroblastic sarcoma (LGMS) is a rare type of tumor. Previous research has paid much attention to reporting pathological analyses of LGMS. However, only few systematic clinical and/or radiological studies have been conducted.

Methods

This study recruited 14 cases (8 males and 6 females) of LGMS. X-ray or computer tomography (CT) scan were performed on 11 cases. MRI was performed on 5 cases.

Results

X-Ray and CT scan: Five cases developed LGMS in bones, including 3 cases in the distal femur, 1 in the right shoulder blade, and another 1 in the right inferior ramus. Massive infiltrative and vermiform bone destruction with poorly-circumscribed lesion margins and partial soft tissue masses were observed. The other 9 cases were developed in soft tissues. Out of them, 4 cases presented slightly irregular hyper- or lower-density masses with poorly-circumscribed margins. 2 cases presented massive calcification and ossification. Significant enhancement was observed in 1 case, while no obvious enhancement was seen in the other 2 cases.

MRI: MR images of 5 cases revealed homogeneous iso- or hyper-signal intensity on T1WI and homogeneous or heterogeneous hyper-signal intensity on T2WI. Enhanced MRI revealed homogeneous enhancement in 2 cases and rim enhancement in 1 case.

Conclusions

Our findings show that LGMS is characterized by invasiveness, metastases and calcification. Different radiological tools should be employed to make an accurate diagnosis.

Low-grade myofibroblastic sarcoma: a case report of a child

Introduction: Myofibroblastic sarcomas are malignant tumors characterized by the increased proliferation of myofibroblasts; they are rare and have been recently discovered. Observation: A 14-year-old adolescent had a large lesion in the inside of her right mandible. The diagnosis, after a difficult histological analysis, was low-grade myofibrosarcoma. The patient was treated with non-interruptive hemimandibulectomy. Discussion: Low-grade myofibroblastic sarcoma is one of four types of myofibroblastic sarcomas recognized by the WHO in the 2001 classification. This classification allows us to determine a prognosis based on histological characteristics of the lesion. Conclusion: In all cases of low-grade myofibroblastic sarcoma, the preferred treatment is curative surgical resection; but still poses a problem in the prosthetic rehabilitation of oral lesion.

Myofibroblastic lesions in the oral cavity: Immunohistochemical and ultrastructural analysis

OBJECTIVE

To immunohistochemically characterize a group of oral myofibroblastic lesions (MLs) and to evaluate the ultrastructural features of myofibroblasts.

MATERIAL AND METHODS

Using a tissue microarray technique (TMA), cases of myofibroma (MF), of nodular fasciitis (NF), of desmoplastic fibroma (DF), and of myofibroblastic sarcoma (MS) from the Universidad Autónoma Metropolitana Xochimilco, and a Private Oral Pathology Service in Mexico City were stained with antibodies against alpha-smooth muscle actin (α-SMA), H-caldesmon, vimentin, desmin, β-catenin, CD34, anaplastic lymphoma protein kinase (ALK-1), and Ki-67.

RESULTS

Nineteen of the 22 MF cases, 2/5 of the NF cases, 1/10 of the DF cases, and 1/2 of the MS cases were positive for α-SMA. 1/2 of the MS cases were positive for desmin; 6/10 of the DF cases were positive for β-catenin, and 2 of the MF cases were positive for ALK-1. All of the MLs were positive for vimentin and negative for H-caldesmon and CD-34. The Ki-67 labeling index in all of the 8/22 MF, 3/5 NF, and 2/2 MS cases was ≥10%. For all of the MLs evaluated, ultrastructural analysis revealed spindle-shaped cells containing endoplasmic reticulum and peripheral actin filament bundles.

CONCLUSION

In certain myofibroblastic lesions, the use of auxiliary techniques (such as immunohistochemistry) can be critical for differential diagnosis.

Low-grade myofibroblastic sarcoma arising in the tip of the tongue with intravascular invasion: A case report

Low-grade myofibroblastic sarcoma (LGMS) is a rare intermediate tumor, which rarely metastasizes and has myofibroblastic differentiation in various sites. It is particularly associated with the tongue in the head and neck region. The lack of any pathological features means it is difficult to make a conclusive diagnosis of LGMS. The immunohistochemical features and genomic rearrangements, including SS18-SSXs and MYH9-USP6s and the genetic mutations of cancer-associated genes, including APC, CTNNB1, EGFR, KRAS, PIK3CA and p53 were examined in a case of LGMS arising in the tip of the tongue. Immunohistochemically, the tumor cells were positive for alpha-smooth muscle actin and vimentin, as in previous reports. They demonstrated neither genomic rearrangements nor point mutations of cancer-associated genes. Although several tumor cells demonstrated intravascular invasion, the MIB-l labeling index of the cells was the same as the original lesion. To the best of our knowledge, this is the first case report of LGMS arising in the tip of the tongue with intravascular invasion.

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

RATIONALE

Low-grade myofibroblastic sarcoma (LGMS) is a malignant lesion composed of myofibroblasts. It is an uncommon tumor of unknown etiology that mainly develops in the bone or soft tissue and is most often reported in the head and neck, particularly in the tongue and oral cavity.

PATIENT CONCERNS

A 2-year-old girl, previously well and with no significant medical history or family history of other diseases, presented with a 2-week painless swelling of the right orbit.

DIAGNOSES

Preoperative computed tomography (CT) revealed a large homogeneous enhanced mass, 21 × 13 mm in size, located on lateral wall of the right orbit with bone absorption. The mass was resected and histopathological examination revealed LGMS of the orbit.

INTERVENTIONS

On May 2016, she underwent surgery without the additional postoperative treatment.

OUTCOMES

The patient's postoperative course was uneventful, and was discharged on the 6th day after surgery. During a year follow-up period, there was no recurrence of the postoperative CT. The patient and her family were satisfied with the result of the surgery.

LESSONS

Based on clinical characteristics and postoperative CT, we considered the mass may be a benign tumor. We completely resected along the capsule without an extensive surgical margin. However, postoperative histopathology diagnose LGMS, which shows a strong potential for local recurrence and vascular invasion. So we should close observation of the patient's symptoms and sign. If the tumor has invaded adjacent tissues, we will use adjuvant chemotherapy or radiotherapy.

Giant low-grade primary myofibroblastic sarcoma of the posterior chest wall

Primary myofibroblastic sarcoma is an extremely rare, highly malignant neoplasm, and only few cases had been reported in the literature worldwide. In the present study, we report an unusual case of a low-grade myofibroblastic sarcoma located in the posterior chest wall with intrathoracic propagation and discuss its clinical and pathological features.

Indolent growth of low-grade myofibroblastic sarcoma of the cheek mimics benign lesions: A case report and literature review

Low-grade myofibroblastic sarcoma (LGMS) is a neoplasm of the soft tissue characterized by myofibroblastic differentiation. This type of tumor has been observed in various sites in the whole body, but frequently occurs in the head and neck region. It typically presents as a slow-growing painless mass, which is often mistaken for a benign lesion due to its indolent growth; however, LGMS is a malignant neoplasm. In the present study, a 43-year-old female presented with a 14-mm LGMS lesion in the buccal subcutaneous tissues of the buccinator muscle. The patient had initially noticed the lesion 2-months prior to presenting at the hospital. Following biopsy, the tumor was surgically resected and no recurrence or metastasis was observed during a follow-up time of 2 years. To the best of our knowledge, this case is the first report of LGMS located in the buccal subcutaneous tissue of the buccinator muscle. The present study a literature review of 55 cases of this tumor type in the head and neck region was conducted, revealing that the indolent growth of these lesions may contribute to a delay in diagnosis. The average time between the onset of clinical symptoms and hospital admission is 3.9 months, and this form of tumor is frequently misdiagnosed as a benign lesion. Therefore, the present study suggests that an incisional biopsy may be performed to rule out LGMS when clinicians encounter patients with the aforementioned indolent lesions anywhere in the body. In addition, the avoidance of radiotherapy is recommended following resection of the LGMS tumor, as it may induce LGMS recurrence.

Myofibroblasts: Master of disguise

Myofibroblasts are the unique population of smooth muscle-like fibroblasts. These cells have a role in growth factors secretion, matrix deposition and degradation. Thereby, myofibroblast contributes in both human physiology and pathology. This review explains the myofibroblastic lesions, imperative role of myofibroblasts in organogenesis, repair, regeneration, inflammation and tumorigenesis.

Low-grade myofibroblastic sarcoma: A population-based study

OBJECTIVES/HYPOTHESIS

Low-grade myofibroblastic sarcoma (LGMS) is a rare entity that is described as having a predilection for occurring in the head and neck region. Here we analyze its demographics, clinic-pathologic, and survival characteristics.

STUDY DESIGN

Retrospective database analysis.

METHODS

A cohort from the Surveillance, Epidemiology, and End Results Program database of cases with LGMS between 2001 and 2012.

RESULTS

There were 49 cases with a 5-year overall survival of 71.6% and disease- specific survival of 76.3%. The majority of cases were in patients <60 years old, female, and white ethnicity. The most common sites were the extremities in 40.8% of cases followed by the head and neck region with 26.5% of cases. Multivariate analysis showed that only older age was significantly associated with worse survival (P < .05).

CONCLUSIONS

LGMS is uncommon in the United States and occurs most commonly in the extremities followed by the head and neck region, despite an existing characterization of a predilection for the head and neck region. Treatment most commonly involves surgery, but the optimal surgical extent and/or radiotherapy needs to be further investigated.

LEVEL OF EVIDENCE

2c Laryngoscope, 127:116-121, 2017.

LOW-GRADE MYOFIBROBLASTIC SARCOMA OF THE LARYNX: CASE REPORT AND REVIEW OF LITERATURE

Low-grade myofibroblastic sarcoma (LGMS) is a very rare, atypical myofibroblastic tumor with fibromatosis-like features with predilection mostly in head and neck region. LGMS occurs primarily in adult patients with a slight male predominance. Only few cases of LGMS affecting the larynx have been reported in literature to this date. We describe a case of low-grade myofibroblastic sarcoma of the larynx in a 40-year-old male patient. The clinicopathological characteristics, immunohistochemical findings and treatment are discussed.

Low-grade myofibroblastic sarcomas of the maxilla

Low-grade myofibroblastic sarcoma (LGMS) is a distinct mesenchymal myofibroblastic malignancy. The tumor may occur at a variety of sites, but is particularly associated with the head and neck. Of the two maxillary sarcomas that were analyzed in the present study, one was misdiagnosed as an inflammatory myofibroblastic tumor during pre-operative excision biopsy, and later presented with a different immunophenotype upon recurrence. Representative paraffin blocks from formalin-fixed tissues were selected from each patient and designated as case 1 and case 2. Immunohistochemical studies were performed on 3-μm thick sections using primary antibodies against α-smooth muscle actin (α-SMA), muscle-specific actin (MSA), desmin, vimentin, calponin, h-caldesmon, fibronectin, cytokeratin, cluster of differentiation 34 (CD34), S-100 protein, anaplastic lymphoma kinase (ALK), epithelial membrane antigen (EMA) and Ki-67. Immunohistochemistry was performed using the streptavidin-biotin-peroxidase complex method. The tumor cells from the two maxillary LGMSs, including the recurrent lesion, were positive for vimentin and fibronectin, and negative for S-100 protein, CD34, EMA, h-caldesmon, ALK, MSA and calponin. The tumor cells from case 1 demonstrated positive staining for α-SMA protein and negative staining for desmin. By contrast, the tumor cells from the primary lesion in case 2 presented with negative staining for α-SMA and positive staining for desmin, while the cells of the recurrent lesion were α-SMA-positive and desmin-negative. The present study concluded that cases of LGMS with immunoprofile alterations are predictive of relatively poor prognoses.