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

Abstract

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.

Myofibroblastic sarcoma in breast: a case report and literature review

“…Furthermore, H-caldesmon is usually expressed positively in leiomyosarcoma but negatively in LGMS, which plays a vital role in the differential diagnosis of the two. Moreover, CK expression is commonly seen in other myofibroblastic proliferations, like the inflammatory myofibroblastic tumor ( 4 ).…”

“…In terms of LGMS at other sites, previous studies have calculated a local recurrence rate of 13.3% to 44.4% ( 5 , 26 , 27 ). In the previous study by Munehisa Kito, 24 patients with LGMS were counted and analyzed statistically ( 4 ). Among them, 22 patients underwent surgical treatment, the results showed that the local recurrence rate was 20%, and the incidence of distant metastasis was 4.2%.…”

“…According to the results, chemotherapy and radiotherapy had no significant benefit on patients’ OS and DSS. Only For unresectable cases, radiotherapy may be a treatment option ( 4 ). However, there have been reports of cases of recurrence outside the irradiated area after radiotherapy in LGMS patients, likely related to the pattern of invasive tumor growth.…”

“…Low-grade myofibroblastic sarcoma (LGMS) was first reported by Mentzel et al in a case series of 18 cases in 1998, and it was classified as a distinct type of soft-tissue tumor by the World Health Organization in 2002 (2,3). LGMS mainly occurs in the head and neck but can also occur in the bones, trunk, limbs, retroperitoneal, and other parts, LGMS in the breast is extremely rare (4)(5)(6). About 20 patients with LGMS of the breast have been previously reported in the literature.…”

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

“…Non-head and neck tumors were present in the abdomen and pelvis or extremities, allowing the tumor to grow silently before symptoms presented [43]. Kito et al [28] showed an association between tumor size and local relapse in his multicenter study investigating different tumor localizations. Tumors in the head and neck region are more easily visible, leading to earlier diagnosis and therapy.…”