Mesenteric fibromatosis involving the superior mesenteric vein: complex resection and reconstruction in a young female.

Primary mesenteric tumors (PMTs) are rare, often presenting asymptomatically until large enough to compress adjacent structures. We present a case of a 36-year-old female with atypical post-cesarean abdominal pain. Imaging revealed an 11 × 10 cm mesenteric mass suggestive of sarcoma or desmoid tumor. Surgical exploration identified a mass involving the mesentery and ileum, necessitating resection of both, along with venous reconstruction of the superior mesenteric vein using a cadaveric graft. A postoperative complication due to venous stasis required a second operation with right colectomy and jejuno-transverse anastomosis. Final pathology confirmed desmoid-type mesenteric fibromatosis. The patient recovered well and remains disease-free and asymptomatic 12 months postoperatively. This case highlights the diagnostic and therapeutic challenges of PMTs, the importance of surgical expertise in vascular reconstruction, and the need for individualized treatment planning to achieve complete tumor resection while minimizing complications such as short bowel syndrome.