Role of Histotripsy in Treatment of Fibrolamellar Hepatocellular Carcinoma in a Pediatric Patient

Document Type

Conference Proceeding

Publication Date

4-2026

Publication Title

Pediatric Blood & Cancer

Abstract

Background: The fibrolamellar subtype of hepatocellular carcinoma (HCC) comprises 25% of HCC cases and has a recurrence rate as high as 77%. Surgical resection is the only curative treatment. Other local control strategies include transarterial chemoembolization, transarterial radioembolization and external beam radiation (EBRT). Histotripsy is a novel non-invasive procedure that destroys targeted tissue using acoustic waves that cavitate tumor cells while sparing critical structures such as blood vessels. In preclinical and clinical studies histotripsy has been shown to induce a secondary immune upregulation which can result in distant tumor response. However, there is currently no published data about its role in pediatric populations and its use in current practice remains based on clinical judgement for recurrent tumors refractory to traditional treatment modalities. We present a case of recurrent fibrolamellar hepatocellular carcinoma involving the Portal vein treated with histotripsy with symptomatic improvement and reduction in circulating tumor DNA despite unchanged imaging results.

Objectives: To discuss effects of histotripsy in a 21-year-old male with fibrolamellar HCC and identify potential areas of research.

Design/Method: Case report.

Results: The patient presented in 2020 with eight months of right shoulder pain and recent fevers. Abdominal CT showed a 10 cm right sided liver mass and IR guided biopsy was consistent with fibrolamellar HCC. Remission after right hepatectomy on 09/2020 followed by lung metastasis in 2021 (surgically resected + Nivolumab/Lenvatinib), porta hepatis node tumor in 2022 (EBRT + gemcitabine/oxaliplatin) and a 4-month interruption in therapy in 2024 due to a non-malignant bowel obstruction. A CT in January 2025 identified a small metastatic lung nodule and a small portal vein tumor thrombus, both worsened despite systemic therapy. He developed symptomatic back pain. The portal vein tumor was unresectable, and he ultimately received outpatient histotripsy on 08/04/2025 without complications. His back pain resolved within 24 h, and he has since been well. His lung tumor was resected 8/22/2025 without complications. Prior to histotripsy, his Signatera ctDNA was increasing and peaked at 14.27 MTM/mL. Following histotripsy, his Signatera decreased to 0.88 MTM/mL on 10/17/2025, but CT on 09/19/2025 showed unchanged involvement of the left lateral portal vein by RECIST criteria.

Conclusion: Tumor resection was important, but Histotripsy of left portal vein tumor thrombus likely contributed to reduction in Signatera tested ctDNA and symptomatic relief in a 21-yearold with recurrent fibrolamellar HCC. Further research in the form of clinical trials evaluating histotripsy in management of fibrolamellar HCC are warranted.

Volume

73

Issue

Suppl 2

First Page

s28

Comments

American Society of Pediatric Hematology/Oncology(ASPHO) Conference, April 29-May 2, 2026, Minneapolis, MN

Helen DeVos Children’s Hospital

Last Page

s28

DOI

10.1002/1545-5017.70343

ISSN

1545-5009

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