Surgical resection of a presacral solitary fibrous tumor with extension to iliac vessels using Karakousis's abdominoinguinal approach: Report of a rare case.

INTRODUCTION AND IMPORTANCE: The solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin, with a reported incidence of 2.8 cases per 100,000 tumors and with distinctive histopathological and immunohistochemical characteristics. It was initially described as a pleural lesion and subsequently, it was found in different organs and tissues. The abdominoinguinal incision described by Karakousis allows a safe and radical approach for lower quadrants abdominopelvic tumors.

CASE PRESENTATION: A 47-year-old man was referred to us with a 5-months history of lower backache radiating to the left lower limb. MRI and CT revealed a retroperitoneal mass of 10 cm extending to left iliac vessels. The initial diagnosis corresponded to a sarcomatous retroperitoneal tumor. It was decided to perform an abdominal exploration using Karakousis's approach for surgical resection. The immunohistochemistry and histopathological study revealed neoplasia compatible with a SFT. It was categorized as low risk for developing metastasis and death from disease, according to the new malignancy criteria. Currently, the patient is asymptomatic and disease-free at 19 months after surgery.

CLINICAL DISCUSSION: Most patients with SFTs present symptoms derived from the tumor growth and the compression on adjacent structures with clinical manifestations that are frequently insidious and precede the tumor discovery. The diagnosis is based on histopathological studies. Nonetheless, when they present an extrathoracic location, they represent a diagnostic challenge, due to their variable histological characteristics.

CONCLUSION: Presacral SFT is a rare entity, with a scant incidence reported regarding this location and long-term treatment. Surgical resection is needed as the immediate treatment.