SMARCB-1–Positive Rhabdoid Squamous Cell Carcinoma Following Liver Transplant: Systematic Review and Unique Case Report

ABSTRACT: We present a rare case of squamous cell carcinoma with rhabdoid features (SCCR), an aggressive histological variant of SCC, in a 63-year-old man with a history of liver transplantation, alongside a review of the literature on previously reported cases (n = 14). SCCR is characterized by large, ovoid, or polygonal carcinoma cells with eosinophilic cytoplasmic inclusions, eccentric nuclei, and prominent nucleoli. While typically associated with INI-1-inactivating mutations and linked to immunosuppression, particularly post-transplantation, the exact pathogenesis of SCCR remains unclear.The patient presented with an ulcerating, elevated mass on the right parietal scalp 5 months post-transplant, while on tacrolimus and mycophenolate therapy. Pathological analysis revealed moderately differentiated SCC with rhabdoid morphology, measuring 13 mm in thickness, extending close to the specimen's base. Immunohistochemistry demonstrated positivity for INI-1, EMA (focal), and CK5/6, with negative staining for desmin, CK18, and CK19.This case highlights the distinct clinical and pathological manifestations of SCCR and underscores the potential for its development following immunosuppression. Increased awareness of this rare and aggressive entity is crucial for timely diagnosis and management.