# Life-Threatening Bleeding From Acquired FXI Inhibitors in a Patient With Colorectal Adenocarcinoma

## TL;DR

A rare case of life-threatening bleeding caused by acquired FXI inhibitors in a patient with colorectal cancer is reported, highlighting the need for early diagnosis and tailored treatment.

## Contribution

This case report presents a rare instance of acquired FXI inhibitors linked to colorectal adenocarcinoma and successful treatment with rFVIIa and corticosteroids.

## Key findings

- Acquired FXI inhibitors were diagnosed in a 60-year-old male with sigmoid colon adenocarcinoma following severe postpolypectomy bleeding.
- Treatment with rFVIIa, tranexamic acid, and corticosteroids controlled the bleeding and resolved the inhibitor.
- The case underscores the importance of early diagnosis and monitoring to prevent relapse in malignancy-associated FXI inhibitor cases.

## Abstract

Acquired inhibitors of coagulation factor XI (FXI) are a rare cause of bleeding disorders, typically associated with autoimmune diseases or malignancies. Although uncommon, these inhibitors can lead to severe bleeding, which can be difficult to manage. A limited number of cases have been reported where acquired FXI inhibitors are associated with malignancy. This case report presented a rare occurrence of acquired coagulation FXI inhibitors in a 60-year-old male with sigmoid colon adenocarcinoma. The patient experienced severe postpolypectomy gastrointestinal bleeding and was diagnosed with FXI inhibitors after laboratory tests revealed prolonged activated partial thromboplastin time (aPTT) and reduced activities of factors IX, XI, and XII. The patient underwent surgery, and life-threatening hemorrhagic shock developed. He was reoperated, and treatment with recombinant factor VIIa (rFVIIa), tranexamic acid, and oral corticosteroids was initiated. The therapy successfully controlled the bleeding and resolved the inhibitor. This case highlights the risk of severe bleeding in patients with acquired FXI inhibitors and emphasizes the importance of early diagnosis and personalized treatment. Regular monitoring is essential due to the risk of relapse, particularly in cases associated with malignancy.