No clear guidelines exist for the management of phlegmasia cerulea dolens. This case report shows how a hybrid approach might be successful. It also shows how rare pathologies can combine to create a life- and limb-threatening condition. . A 75-year-old man, known for nephrotic syndrome currently under investigation, presented to the emergency department with a 24-hour history of left leg swelling followed by intense pain. The left lower limb showed a phlegmasia cerulean dolens. Renal function, coagulation profile, and inflammatory parameters were normal; D-Dimers 5,6 mg/L. The CT scan showed juxtarenal thrombosis of the hypoplastic IVC, involving both renal veins, reaching the left iliac-femoral-popliteal axis, with collateralization to the pelvic and mesenteric veins, associated with bilateral segmental pulmonary embolisms. A suspected left breast nodule was also found. Intravenous heparin was immediately administered, and urgent hybrid procedure with surgical thrombectomy and venous angiography and thromboaspiration, liberating the iliolumbar collaterals, was performed. A lateral leg fasciotomy was mandatory due to the phlegmasia cerulea. Postoperative Doppler US showed a good venous compressibility of the left leg. Thrombophilia screening was negative. The breast nodule was biopsied showing an invasive ductal carcinoma. The patient was discharged with oral rivaroxaban and indication for left mastectomy and oncological therapy with aromatase inhibitors.