Giant Intra-Abdominal Desmoid Tumor in a Young Man: A Case Report and Literature Review

INTRODUCTION: Desmoid tumors are rare soft-tissue tumors with a high recurrence rate; however, histologically, these tumors are benign. We describe a case in which a giant desmoid tumor was resected in a young man without any apparent causative factors. CASE PRESENTATION: A 21-year-old man was referred to our hospital for treatment after presenting to a nearby hospital with right inguinal pain. Abdominal magnetic resonance imaging showed an intra-abdominal mass measuring 34 x 15 x 8 cm with partial signal hyperintensity on T2-weighted imaging and hypointensity on T1-weighted imaging, extending from the left abdominal cavity to the pelvic region. Although no definitive diagnosis was obtained preoperatively, surgery was performed under suspicion of gastrointestinal stromal tumor or other significant disease. A mass was identified firmly adherent to the transverse colon, gastric wall, and diaphragm, and these organs were partially resected. The excised specimen measured 38 x 21 x 8 cm and weighed 6400 g. Macroscopically, the tumor showed a smooth surface and homogeneous interior. Pathological examination revealed atypical cells with spindle-shaped nuclei and collagen fiber hyperplasia in the stroma, and immunostaining was negative for c-kit, CD34, desmin, S-100, and positive for beta-catenin, leading to a confirmed diagnosis of desmoid tumor. Fifteen months after surgery, a local recurrence with a diameter of 3.0 cm was identified, and the patient remains under careful follow-up. CONCLUSIONS: Intra-abdominal desmoid tumors larger than 30 cm are extremely rare. When encountering a young patient with a large intra-abdominal tumor, the possibility of desmoid tumor should be considered.