A Rare Case Of Extra-Abdominal Desmoid-Type Fibromatosis Arising From The Popliteal Fossa

Desmoids are rare soft-tissue tumors of the abdominal wall that may sporadically occur extra abdominally. It manifests as clonal fibroblastic proliferation with an infiltrative tendency and capacity to recur without metastasizing. An adolescent male presented with a gradually increasing globular, non-tender, firm, non-pulsatile swelling (8 x 5 x 3 cm(3) ) in the left popliteal fossa that had been present for five months. Following thorough investigation with imaging and Tru-cut biopsy, finally, an excisional biopsy was done. Histopathological examination confirmed a desmoid tumor, and the patient received adjuvant radiotherapy. At the one-year postoperative follow-up, there was no recurrence; the patient had been explained the prognosis. This case highlights a rare site of an extra-abdominal desmoid but with classical clinical presentation, imaging, intraoperative, and histopathological findings. Awareness and knowledge of this entity are of paramount importance for clinical practitioners.