# Giant Primary Hepatic Endodermal Sinus Tumor: Multidisciplinary Management and Long‐Term Survival

## TL;DR

A rare case of a liver tumor initially mistaken for cancer was successfully treated with surgery and chemotherapy, leading to long-term survival.

## Contribution

This case highlights the importance of early biopsy and multidisciplinary treatment for primary hepatic endodermal sinus tumors.

## Key findings

- A 34-year-old woman with a hepatic mass and elevated AFP was diagnosed with primary hepatic EST after surgery.
- Multidisciplinary treatment including surgery and chemotherapy led to complete response and long-term survival.
- Early diagnosis and systemic treatment are critical for chemosensitive tumors like primary hepatic EST.

## Abstract

The endodermal sinus tumor (EST), also known as yolk sac tumor, accounts for 20% of germ cell tumor cases, typically occurring in gonadal locations. However, 1%–5% can present with an extragonadal localization. Primary hepatic EST is an extremely rare entity and poses a diagnostic challenge for the appropriate management of this pathology. We present the case of a 34‐year‐old woman who presented with a single hepatic mass associated with elevated alpha‐fetoprotein (AFP) levels. Initially, hepatocellular carcinoma (HCC) was suspected, leading to a right hepatectomy, which resulted in pathology findings consistent with an EST. Following surgery, the patient underwent four courses of BEP chemotherapy, showing a partial response with residual lesions. The patient received two more courses of EP chemotherapy, with a PET CT showing a complete response. At over 5 years of follow‐up, the patient remains clinically stable, with negative tumor markers, no evidence of disease, and leading a normal life. Primary hepatic EST is an infrequent but important differential diagnosis of HCC, particularly in young women without cirrhosis who present with markedly elevated AFP levels. Early biopsy confirmation and multidisciplinary management are essential, as this chemosensitive tumor may achieve long‐term survival with timely systemic treatment.