Low-grade fibromyxoid sarcoma (LGFMS) was first described by Evans in 1987, and since then, just over 150 cases have been reported, showing the rarity of this tumor. We report the clinical case of a 56-year-old man with a swelling on the distal third of the left thigh. The mass had grown in the course of 1 year and was surgically excised, obtaining complete resolution. Immuno-histological examination demonstrated the lesion to be a LGFMS, defined as a benign tumor but with a high incidence of local and distant recurrence (5-10%). At 2-year follow-up the patient was disease-free, confirming the efficacy of the surgical excision. In literature, the frequency of incomplete excision of LGFMS due to inappropriate diagnosis is stressed. It is this element that contributes most to the high rate of recurrence. We recommend that the eventuality of observing this rare tumor be borne in mind, and that care be taken to perform a complete, ample excision.