Early diagnosis and treatment of low-grade myofibroblastic sarcoma in the left distal femur: a case report and literature review.

Abstract

Background: Low-grade myofibroblastic sarcoma (LGMS) is a rare malignant tumor with a predilection for soft tissue and bone. This is a rare malignant tumor with diagnostic challenges, often leading to misdiagnosis as other similar diseases. As a result, its exact incidence remains unclear. While pathologic studies have been reported, systematic clinical, radiological, and therapeutic evaluations remain limited.

Methods: This study presented a case of LGMS located in the left distal femur treated with distal femoral resection and total knee arthroplasty using a tumor knee joint system. A review of 24 published cases was conducted for comparative analysis, focusing on clinical presentations, radiological features, immunohistochemical findings, treatment strategies, and long-term outcomes.

Results: Radiological analysis revealed a tumor confined to the distal femoral medullary cavity without cortical destruction or lytic changes. Immunohistochemical staining demonstrated: SMA (+), p53 (+), Ki-67 (30% +), CD163 (+), and CD68 (+), confirming the diagnosis of LGMS. Postoperatively, the patient reported significant pain relief and functional recovery at five months, with VAS, WOMAC, and HSS scores indicating improved joint function. The literature review highlighted LGMS's predilection for local recurrence, emphasizing the importance of early diagnosis and surgical intervention.

Conclusion: LGMS demonstrates unique radiological and pathological features depending on its site of origin. Our case underscores the utility of wide excision and TKA in managing bone-involved LGMS. Further studies are needed to evaluate long-term outcomes and optimize management strategies.