Primary adenosquamous carcinoma of the appendix with genomic profiling of the adenocarcinoma and squamous cell carcinoma components using next-generation sequencing

Adenosquamous carcinoma (ASC) is characterized by the presence of adenocarcinoma and squamous cell carcinoma components in one tumor. Primary appendiceal ASC is extremely rare, and only 7 cases have been reported in the medical literature. We present a case of primary appendiceal ASC, where both tumor components were subjected to next-generation sequencing. Both components shared the same BRAF, TP53, PLCG2 , and RUNX1 variants, but only the adenocarcinoma component demonstrated a mutation in the SMAD4 gene. This suggests appendiceal ASC components may diverge from a shared evolutionary clone. We then discuss the therapeutic implications of our findings. To our knowledge, this is the first next-generation sequencing analysis performed on appendiceal ASC.