Background Long-term placements of central venous catheters (CVCs) are known to cause various complications, among which include fibrin sheath formation, causing catheter dysfunction, infection and thrombosis. Post-catheter removal, these sheaths may sometimes be retained in the vein; however, are rarely calcified. When retained sheaths are calcified, they may cause diagnostic confusion on imaging, as they may mimic a retained catheter fragment. Case presentation We report a case of a patient with end-stage renal disease and a history of multiple prior CVC insertions presenting with symptoms of central venous occlusion post-revascularization of his stenosed arteriovenous fistula. CT venography revealed a linear tubular hyperdensity within the right brachiocephalic vein and superior vena cava, which at first glance looked like a retained catheter fragment. However, further scrutiny revealed a retained calcified intravascular fibrin sheath as the cause of occlusion. Conclusions Awareness of the radiological discriminating features of calcified fibrin sheaths are important to prevent misdiagnosis and unnecessary interventions as these sheaths may mimic retained catheter fragments. Calcified fibrin sheaths should also be considered as a differential diagnosis of radio-opaque intravascular structures or venous calcifications post-CVC removal.