Surgical management of pseudotumor secondary to Factor X deficiency: a case report.

Introduction and importance: Pseudotumor is a rare but serious complication of bleeding disorders. Its occurrence in Factor X (FX) deficiency is exceptionally uncommon. This report highlights a rare case of FX deficiency presenting as a large pseudotumor managed successfully by surgical excision. Presentation of case: A 31-year-old man presented with a painful, progressively enlarging swelling over the left flank. Imaging revealed a large retroperitoneal mass with erosion of the left iliac bone. Coagulation studies showed prolonged prothrombin time and reduced FX activity, confirming FX deficiency. He was treated perioperatively with prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP), followed by open surgical evacuation of an organized hematoma. Postoperative recovery was uneventful, with no recurrence at 2-month follow-up. Clinical discussion: Pseudotumor secondary to FX deficiency is extremely rare and can mimic soft tissue or bone malignancy. Early imaging and biopsy are essential for diagnosis. Definitive management involves factor replacement and surgical excision in large or symptomatic cases. In centers where FX concentrate is unavailable, PCC and FFP provide effective hemostatic coverage. This case underscores the importance of a multidisciplinary approach and resource-adapted management, which can achieve favorable outcomes even in low-resource settings. Conclusion: Surgical excision with adequate perioperative PCC/FFP support remains a safe and effective strategy for large pseudotumors secondary to FX deficiency.