# Spontaneous Regression of Intrahepatic Adenocarcinoma after Needle Biopsy: A Case Report and Literature Review

## TL;DR

A rare case of liver cancer spontaneously regressing after a biopsy suggests a possible immune system response.

## Contribution

This case report documents spontaneous regression of intrahepatic adenocarcinoma following a biopsy, potentially linked to immune activation.

## Key findings

- A liver lesion confirmed as adenocarcinoma via EUS-FNA later showed no viable cancer cells.
- The tumor was replaced by epithelioid granulomas with CD8-positive T cell infiltration.
- This suggests an immune-mediated tumor regression following biopsy.

## Abstract

Spontaneous tumor regression (STR) is a rare phenomenon in which cancer cells partially or completely disappear without treatment. We report a case of intrahepatic cholangiocarcinoma demonstrating STR following endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA).

A 77-year-old male presented with acute cholecystitis 1 day after percutaneous coronary intervention for acute myocardial infarction. Conservative treatment and endoscopic retrograde gallbladder drainage were performed due to antiplatelet therapy. Cytology of bile juice unexpectedly revealed adenocarcinoma. Further imaging, including CT and mapping biopsy, failed to detect a tumor. Laparoscopic cholecystectomy with gallbladder bed resection showed no histological evidence of malignancy. Four months later, surveillance CT revealed a 15 × 15 mm lesion in segment 3 of the liver. EUS-FNA confirmed adenocarcinoma. Laparoscopic left lateral resection was performed; however, no viable cancer cells were identified, and the lesion was replaced by epithelioid granulomas. Immunohistochemistry demonstrated dense infiltration of CD8-positive cytotoxic T cells, suggesting an immune-mediated regression of the tumor.

This case highlights the possibility of tumor regression in intrahepatic adenocarcinoma following EUS-FNA, potentially triggered by an immune response.