806 - An atypical presentation of Fibromyxosarcoma in a young Adult

Case Diagnosis: Left Proximal Femur Myxofibrosarcoma

Case Description: A 32-year-old male presenting with severe left lumbosacral pain, refractory to multimodal pain management, physical therapy, and sacroiliac joint steroid injections. Pain worsened over time despite an optimized pain regimen, impacting his mobility, and quality of life and leading to excessive self-medicating with over-the-counter anti-inflammatories. PM&R clinical reassessment notable for 4-year evolution of deteriorating clinical status without neurological deficits. MRI pelvis was ordered, which showed an incidental femoral lesion. Needle biopsy was concerning for sarcoma. The patient underwent a wide sarcoma resection with left proximal femur reconstruction and radiotherapy due to the risk of malignancy. The pathology report was positive for myxofibrosarcoma.

Discussions: Myxofibrosarcoma is an uncommon subtype of soft tissue sarcoma that is rarely seen in the non-elderly. Surgery is a first-line treatment due to high rates of recurrence and metastasis. The atypical presentation of this young, otherwise healthy adult warranted aggressive intervention due to the increased risk of malignancy conversion per needle biopsy results. PM&R service coordinated necessary services including medical and orthopedic oncology, radiotherapy, wound care, and fertility clinic. After treatment, the patient was pain-free and only required assistive devices for longer distances.

Conclusions: This case illustrates the importance of keeping a high degree of suspicion regarding red flags within the rehabilitation setting, to prevent a delayed diagnosis. Alarming symptoms, in this case, included worsening refractory pain out of proportion to the original diagnosis and progressive physical disability in an otherwise physically active young adult. In this case, tumor differentiation and invasion were precluded by the implementation of limb salvage and cancer rehabilitation strategies, preventing the tumor from metastasizing, or invading local structures. This case highlights the importance of rehabilitation management in the coordination of multiple medical services required for successful clinical outcomes.