Supplementary Material for: Paraneoplastic pemphigus and liver biopsy needle track dissemination in hepatocellular carcinoma: a case report

Introduction: Hepatocellular carcinoma (HCC) is a common and aggressive liver cancer, typically arising in cirrhotic livers but can also occur in the absence of cirrhosis. Paraneoplastic pemphigus (PNP) is a rare autoimmune blistering disorder mostly linked to hematologic malignancies; its association with HCC is extremely uncommon and poses significant diagnostic and therapeutic challenges, particularly due to the need for immunosuppression in PNP management, which may limit systemic cancer therapies. Case Presentation: We report an 80-year-old male with no prior liver disease presenting with painful oral erosions, weight loss, and hepatomegaly. Imaging revealed a large liver mass without signs of cirrhosis. Biopsy confirmed well-differentiated HCC (BCLC stage C). Concurrently, skin biopsy and positive autoantibodies (anti-desmoglein 3, anti-envoplakin) established the diagnosis of PNP. High-dose corticosteroids and intravenous immunoglobulin led to significant mucocutaneous improvement. Systemic HCC therapy with sorafenib was started, as immunotherapy was contraindicated due to PNP. Despite treatment, disease progression occurred, including needle tract seeding at the biopsy site. The patient discontinued treatment and died 16 months after diagnosis. Conclusions: This case illustrates a rare and diagnostically complex association of PNP with HCC in a non-cirrhotic liver. It highlights how immunosuppressive therapy for PNP may adversely affect tumor control and potentially accelerate disease progression. Additionally, it underscores the risk of tumor seeding after liver biopsy, especially in immunosuppressed patients. Recognizing these complexities is essential to guide appropriate diagnosis and therapeutic approaches in similar cases.