# A rare case of undifferentiated embryonal sarcoma of the liver in an elderly patient misdiagnosed as intrahepatic cholangiocarcinoma

## TL;DR

An 88-year-old man was misdiagnosed with liver cancer but later found to have a rare childhood tumor, highlighting the need for better awareness in diagnosing such cases in the elderly.

## Contribution

This is the oldest reported case of undifferentiated embryonal sarcoma of the liver, expanding its known age range and emphasizing diagnostic challenges in elderly patients.

## Key findings

- UESL was misdiagnosed as intrahepatic cholangiocarcinoma due to atypical imaging and mild CA19–9 elevation.
- UESL in elderly patients shows aggressive behavior with rapid recurrence and poor prognosis despite surgery.
- Pathological confirmation via IHC is essential for accurate UESL diagnosis when imaging and serology are inconclusive.

## Abstract

Undifferentiated embryonal sarcoma of the liver (UESL) is an exceptionally rare and aggressive malignancy, predominantly affecting children. Its occurrence in the elderly is exceedingly uncommon, posing significant diagnostic challenges. We present the oldest-reported case of UESL, initially misdiagnosed as intrahepatic cholangiocarcinoma (iCCA).

An 88-year-old male presented with an upper abdominal mass and discomfort. Imaging (CT/MRI/PET-CT) and mildly elevated CA19–9 initially suggested iCCA (T1bN0M0, Stage IB). After 10 months of disease progression despite chemotherapy (capecitabine), left hemihepatectomy was performed. Histopathological examination revealed UESL (7.5 cm tumor; IHC: Vimentin+, CD10+, CD56+, Ki-67 80 %). The patient developed recurrent hepatic disease and pulmonary metastases 1.5 months postoperatively and succumbed to the disease shortly thereafter, with an overall survival of approximately one year.

UESL in octogenarians is exceptionally rare, with nonspecific imaging and serological findings (e.g., mild CA19–9 elevation) leading to frequent misdiagnosis, often as iCCA. Pathological examination remains essential for definitive diagnosis. Despite radical resection, prognosis in elderly patients is poor due to aggressive biology and limited tolerance for adjuvant therapy. This case underscores the importance of considering UESL in atypical liver masses across all age groups.

UESL should be included in the differential diagnosis of atypical liver masses, even in elderly patients. Early surgical resection offers the best chance for survival, though outcomes remain dismal in advanced age due to rapid recurrence and metastasis. Heightened awareness of this entity is crucial to mitigate diagnostic delays.

•Oldest UESL case in an 88-year-old, expanding the age spectrum of this rare cancer.•Misdiagnosed as iCCA due to atypical imaging & mild CA19-9 rise, showing UESL's diagnostic complexity in elderly.•Rapid recurrence (liver & lung mets) 1.5 months post-surgery, poor prognosis in elderly despite resection.•UESL confirmed by IHC (Vimentin, CD56+, Ki-67 80%) after inconclusive imaging/serology.•Consider UESL in differentials for atypical liver masses in all ages to reduce diagnostic delay.

Oldest UESL case in an 88-year-old, expanding the age spectrum of this rare cancer.

Misdiagnosed as iCCA due to atypical imaging & mild CA19-9 rise, showing UESL's diagnostic complexity in elderly.

Rapid recurrence (liver & lung mets) 1.5 months post-surgery, poor prognosis in elderly despite resection.

UESL confirmed by IHC (Vimentin, CD56+, Ki-67 80%) after inconclusive imaging/serology.

Consider UESL in differentials for atypical liver masses in all ages to reduce diagnostic delay.