Solid pseudopapillary tumor of the pancreas: Clinical, histopathological, and molecular findings in a cohort of Mexican patients

INTRODUCTION AND AIMS: Solid pseudopapillary tumor of the pancreas (SPTP) is a rare pancreatic neoplasm of low malignant potential. It predominantly affects young women and raises ongoing questions about its origin and behavior. We aimed to evaluate somatic mutations of the β-catenin (CTNNB1) gene in Mexican patients with SPTP and assess clinical and molecular genotype-phenotype correlations in this rare tumor. MATERIALS AND METHODS: A cross-sectional study of SPTP patients (1997-2023) was conducted at a tertiary care medical center. Tumor and non-affected pancreatic tissue samples underwent staining, immunohistochemistry testing, DNA extraction, and CTNNB1 gene exon-3 sequencing. RESULTS: Of the 37 cases of SPTP studied, 36 were female, and one was male. Most tumors of variable sizes occurred in the pancreatic head or tail (78.4%). Immunohistochemical studies always revealed β-catenin expression and pathological analysis confirmed lymph node invasion. CTNNB1 gene sequencing showed mutations in 34 of 37 tumors (91.9%), exclusively affecting codons 32, 33, 34, and 37. CONCLUSIONS: The results show clinical and immunohistochemical associations with pancreatic tumor location, tissue invasion, and specific gene mutations. These findings highlight the prevalence of CTNNB1 mutations in SPTP and underscore the significance of examining population diversity in rare tumor research to determine the likelihood of clinical and molecular correlations for personalized treatment.