Intratumoral Para-Toluenesulfonamide (PTS) Injection for Recurrent Hepatocellular Carcinoma Adjacent to the Heart: A Case Report.

Abstract

Recurrent hepatocellular carcinoma (HCC) adjacent to the heart is difficult to treat when surgery and conventional locoregional therapies are no longer feasible. We report an 87-year-old man with recurrent segment VIII HCC that remained viable after radiofrequency ablation, six sessions of transarterial embolization (TAE), and stereotactic body radiation therapy (SBRT). Following multidisciplinary review and regulatory approval for compassionate-use, the patient underwent CT-guided intratumoral para-toluenesulfonamide (PTS) injection. PTS (330 mg/mL) was administered as 5.0 mL on 13 March 2025 and 6.0 mL on 17 March 2025. A small residual enhancing focus was subsequently treated with an additional 0.5 mL on 24 June 2025, giving a total cumulative volume of 11.5 mL. Serial contrast-enhanced computed tomography showed progressive loss of arterial enhancement. Complete response according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) was documented in September 2025 and was sustained on follow-up CT obtained on 15 April 2026, with no evidence of local recurrence. Serum alpha-fetoprotein remained below 3.0 ng/mL and liver function was preserved. A small pneumothorax and transient post-procedural pain resolved with conservative management; no severe or life-threatening treatment-related adverse events were documented. This case suggests that CT-guided intratumoral PTS injection may represent a feasible salvage local treatment strategy for carefully selected patients with anatomically challenging recurrent HCC when established locoregional options are no longer feasible.