[Pancreatic acinar cell carcinoma: Clinical and theranostic characteristics]

Pancreatic Acinar Cell Carcinoma (PACC) are a uncommon histological subtype (around 1-2%) of pancreatic adenocarcinoma. These tumors derive from acinar cells and may be associated with mixed histologies such as neuro-endocrine or ductal excreto-pancreatic contingents. The histological diagnosis of acinar differentiation relies on morphology and immunohistochemistry using anti-BCL10 immunohistochemical staining. Due to the low prevalence of PACC, dedicated studies are difficult to conduct and PACC management is similar to that of ductal adenocarcinoma (PDAC) in international guidelines. Retrospective studies appear to show larger but less aggressive tumors, with fewer lymph node involvement and a more favorable prognosis than PDAC. Recent research also highlighted a different carcinogenesis. Unlike PDAC, KRAS mutations are unfrequent, but Homologous Recombination Deficiencies (HRD) are commonly found (30% of cases). In most cases, they are associated with germline mutations, notably BRCA2, which may offer an opportunity for genetic counselling. Other molecular alterations, such as BRAF (approximately 3%) or MMR deficiency (2-4%), have also been reported. Thus, the identification of pancreatic acinar cell carcinoma should trigger theranostic molecular analyses for treatment personalization.