{"entity":{"id":"pancreatic-acinar-cell-carcinoma","kind":"cancer","name":"Pancreatic acinar cell carcinoma","aka":["Acinar cell carcinoma","ACC of the pancreas","Acinar carcinoma","Mixed acinar-neuroendocrine carcinoma"],"tldr":"Pancreatic acinar cell carcinoma is a rare pancreatic cancer that grows from the enzyme-making cells rather than the ducts. It forms large soft masses, can pour lipase into the blood and cause fat lumps under the skin and joint pain, usually lacks the KRAS mutation, often carries DNA repair faults or BRAF fusions, and responds better to bowel-cancer-style chemotherapy than to gemcitabine.","summary":"Acinar cell carcinoma arises from the exocrine cells that make digestive enzymes. Tumours are typically large, well circumscribed and soft, more often in the head, and are diagnosed by biopsy with immunohistochemistry for trypsin, chymotrypsin and BCL10; a minority are mixed acinar-neuroendocrine carcinomas. About one in ten patients has the lipase hypersecretion syndrome of subcutaneous fat necrosis, polyarthralgia and eosinophilia, and serum lipase and alpha-fetoprotein can serve as tumour markers. Metastases at diagnosis are common, most often to the liver.\n\nThe genetics differ sharply from ductal adenocarcinoma: KRAS mutations are rare, and instead sequencing finds recurrent BRAF or RAF1 fusions (SND1-BRAF and others) in roughly a fifth to a quarter of cases, alterations in homologous recombination genes including germline BRCA2 and PALB2 in a substantial minority, mismatch repair deficiency in a few, and APC or CTNNB1 changes in the Wnt pathway. Every patient should therefore have germline and tumour sequencing, and germline testing has consequences for relatives.\n\nSurgery is the only curative treatment and is offered even for large tumours and selected metastatic disease, because outcomes after resection are better than for ductal adenocarcinoma. There is no randomised evidence for systemic treatment; retrospective series show that fluoropyrimidine and oxaliplatin regimens (FOLFOX, FOLFIRINOX) produce more responses than gemcitabine-based treatment, which is why guidelines favour them. Tumours with BRAF fusions respond to MEK inhibitors in case reports, homologous recombination-deficient tumours to platinum and PARP inhibitors, and mismatch repair deficient tumours to pembrolizumab. Mixed acinar-neuroendocrine tumours are treated as acinar cell carcinoma.","asOf":"2026-09-18","wikipedia":"https://en.wikipedia.org/wiki/Acinar_cell_carcinoma_of_the_pancreas","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Acinar_cell_carcinoma_of_the_pancreas"},{"label":"NCCN Guidelines: Pancreatic Adenocarcinoma","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455"}],"tags":["subtype-page","gastrointestinal"],"related":["kras-wild-type-pdac","resectable-pdac","metastatic-pdac","brca-palb2-pdac","pancreatoblastoma","pancreatic-net"],"cancers":[],"sections":[],"technologies":["cytotoxic-chemotherapy","cgp","germline-testing","robotic-surgery","parp-inhibitor","checkpoint-inhibitor"],"targets":["braf","brca","kras"],"drugs":["folfox","folfirinox","oxaliplatin","fluorouracil","gemcitabine","olaparib","dabrafenib-trametinib","pembrolizumab"],"companies":[],"institutions":[],"pathways":["ras-mapk","homologous-recombination-repair","wnt","pancreatic-cancer-signalling"],"terms":["gene-fusion","hrd","gbrca-mutation","whipple","msi","tumour-grade","oligometastatic"],"trials":[],"people":["eileen-oreilly","anirban-maitra","richard-schulick"],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"gastrointestinal","burden":"About 1 to 2 percent of pancreatic cancers in adults, and the commonest pancreatic cancer in children after pancreatoblastoma; it affects men more often than women and presents at a median age around 60.","subtypes":["Pure acinar cell carcinoma (trypsin and BCL10 positive; usually KRAS wild-type rather than ductal PDAC)","Mixed acinar-neuroendocrine carcinoma (treated as acinar cell carcinoma)","Acinar cell carcinoma with a BRAF or RAF1 fusion (MEK inhibitor candidates)","Acinar cell carcinoma with germline BRCA2 or PALB2 or other homologous recombination defects (platinum, PARP inhibitors)","Acinar cell carcinoma with lipase hypersecretion syndrome","Paediatric acinar cell carcinoma (rare; distinguished from pancreatoblastoma)"],"biomarkers":["Trypsin, chymotrypsin and BCL10 immunohistochemistry (diagnosis)","Serum lipase and alpha-fetoprotein (markers in a subset)","BRAF or RAF1 fusions (SND1-BRAF and others)","Germline and somatic BRCA2, PALB2, ATM and other homologous recombination genes","Mismatch repair status","APC or CTNNB1 alterations; KRAS usually wild-type"],"standardOfCare":[{"setting":"Diagnosis","approach":"Biopsy with acinar markers; CT staging; germline testing and comprehensive tumour sequencing with fusion detection for every patient.","refs":["endoscopic-ultrasound-systems","ct","germline-testing","cgp"],"guideline":{"version":"NCCN Guidelines: Pancreatic Adenocarcinoma","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455"}},{"setting":"Resectable","approach":"Pancreatoduodenectomy or distal pancreatectomy even for large tumours, with adjuvant chemotherapy by extrapolation from ductal adenocarcinoma, usually a fluoropyrimidine and oxaliplatin regimen.","refs":["whipple","folfox","folfirinox","neoadjuvant-adjuvant"],"guideline":{"version":"NCCN Guidelines: Pancreatic Adenocarcinoma","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455"}},{"setting":"Advanced","approach":"FOLFOX or FOLFIRINOX preferred over gemcitabine-based regimens on retrospective evidence; resection of the primary and limited metastases considered after response.","refs":["folfox","folfirinox","oxaliplatin","fluorouracil","oligometastatic"],"guideline":{"version":"NCCN Guidelines: Pancreatic Adenocarcinoma","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455"}},{"setting":"Molecularly selected","approach":"MEK inhibition for BRAF fusions on case-series evidence; platinum and PARP inhibitors for homologous recombination defects; pembrolizumab for mismatch repair deficiency.","refs":["dabrafenib-trametinib","olaparib","pembrolizumab","gene-fusion","hrd"],"guideline":{"version":"NCCN Guidelines: Pancreatic Adenocarcinoma","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455"}}],"stateOfArt":["Recognition that acinar cell carcinoma is molecularly distinct from ductal adenocarcinoma, with BRAF fusions and DNA repair defects rather than KRAS.","Fluoropyrimidine and oxaliplatin regimens have replaced gemcitabine as the usual chemotherapy.","Surgery is offered more liberally than in ductal adenocarcinoma because resected patients do better.","Molecular tumour boards match fusions and repair defects to drugs approved in other cancers."],"history":[{"year":1908,"title":"Berner describes acinar cell carcinoma of the pancreas as a distinct tumour","refs":["whipple"]},{"year":1992,"title":"Klimstra and colleagues define the clinicopathological features of acinar cell carcinoma","refs":["tumour-grade"]},{"year":2014,"title":"Sequencing shows BRAF and RAF1 fusions and DNA repair gene defects, and rare KRAS mutation","refs":["gene-fusion","braf","brca"]},{"year":2018,"title":"Retrospective series favour fluoropyrimidine and oxaliplatin regimens over gemcitabine","refs":["folfox","folfirinox"]}],"pipeline":["pdac-organoid-pharmacotyping","cgp"],"openProblems":["No prospective trial has ever been completed in acinar cell carcinoma; all systemic therapy evidence is retrospective.","BRAF fusions have no approved drug and MEK inhibitor evidence is case reports.","The tumour is often misdiagnosed as neuroendocrine or ductal cancer on small biopsies.","Registries are small and international collaboration is needed for any trial."],"parent":"pancreatic"},"route":"/cancers/pancreatic-acinar-cell-carcinoma/","neighbours":{"cancer":[{"id":"brca-palb2-pdac","kind":"cancer","name":"BRCA or PALB2-mutant pancreatic ductal adenocarcinoma","route":"/cancers/brca-palb2-pdac/"},{"id":"ipmn-cystic-precursors","kind":"cancer","name":"Intraductal papillary mucinous neoplasm and other pancreatic cystic precursors","route":"/cancers/ipmn-cystic-precursors/"},{"id":"kras-wild-type-pdac","kind":"cancer","name":"KRAS wild-type pancreatic ductal adenocarcinoma","route":"/cancers/kras-wild-type-pdac/"},{"id":"metastatic-pdac","kind":"cancer","name":"Metastatic pancreatic ductal adenocarcinoma","route":"/cancers/metastatic-pdac/"},{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"},{"id":"pancreatic-net","kind":"cancer","name":"Pancreatic neuroendocrine tumours","route":"/cancers/pancreatic-net/"},{"id":"pancreatoblastoma","kind":"cancer","name":"Pancreatoblastoma","route":"/cancers/pancreatoblastoma/"},{"id":"resectable-pdac","kind":"cancer","name":"Resectable pancreatic ductal adenocarcinoma","route":"/cancers/resectable-pdac/"}],"technology":[{"id":"cgp","kind":"technology","name":"Comprehensive genomic profiling","route":"/technologies/cgp/"},{"id":"ct","kind":"technology","name":"CT (computed tomography)","route":"/technologies/ct/"},{"id":"cytotoxic-chemotherapy","kind":"technology","name":"Cytotoxic chemotherapy","route":"/technologies/cytotoxic-chemotherapy/"},{"id":"endoscopic-ultrasound-systems","kind":"technology","name":"Endoscopic ultrasound and EBUS systems","route":"/technologies/endoscopic-ultrasound-systems/"},{"id":"germline-testing","kind":"technology","name":"Germline (hereditary) testing","route":"/technologies/germline-testing/"},{"id":"checkpoint-inhibitor","kind":"technology","name":"Immune checkpoint inhibitors","route":"/technologies/checkpoint-inhibitor/"},{"id":"parp-inhibitor","kind":"technology","name":"PARP inhibitors","route":"/technologies/parp-inhibitor/"},{"id":"pdac-organoid-pharmacotyping","kind":"technology","name":"PDAC organoid pharmacotyping","route":"/technologies/pdac-organoid-pharmacotyping/"},{"id":"robotic-surgery","kind":"technology","name":"Robotic & minimally invasive surgery","route":"/technologies/robotic-surgery/"}],"target":[{"id":"braf","kind":"target","name":"BRAF","route":"/targets/braf/"},{"id":"brca","kind":"target","name":"BRCA1 / BRCA2 (HRD)","route":"/targets/brca/"},{"id":"kras","kind":"target","name":"KRAS","route":"/targets/kras/"}],"drug":[{"id":"dabrafenib-trametinib","kind":"drug","name":"Dabrafenib + trametinib","route":"/drugs/dabrafenib-trametinib/"},{"id":"fluorouracil","kind":"drug","name":"Fluorouracil (5-FU)","route":"/drugs/fluorouracil/"},{"id":"folfirinox","kind":"drug","name":"FOLFIRINOX / mFOLFIRINOX","route":"/drugs/folfirinox/"},{"id":"folfox","kind":"drug","name":"FOLFOX (5-FU, leucovorin, oxaliplatin)","route":"/drugs/folfox/"},{"id":"gemcitabine","kind":"drug","name":"Gemcitabine","route":"/drugs/gemcitabine/"},{"id":"olaparib","kind":"drug","name":"Olaparib","route":"/drugs/olaparib/"},{"id":"oxaliplatin","kind":"drug","name":"Oxaliplatin","route":"/drugs/oxaliplatin/"},{"id":"pembrolizumab","kind":"drug","name":"Pembrolizumab","route":"/drugs/pembrolizumab/"}],"pathway":[{"id":"homologous-recombination-repair","kind":"pathway","name":"Double-strand break repair: HR versus end joining","route":"/pathways/homologous-recombination-repair/"},{"id":"pancreatic-cancer-signalling","kind":"pathway","name":"Pancreatic cancer (KEGG map)","route":"/pathways/pancreatic-cancer-signalling/"},{"id":"ras-mapk","kind":"pathway","name":"RAS / RAF / MEK / ERK (MAPK)","route":"/pathways/ras-mapk/"},{"id":"wnt","kind":"pathway","name":"Wnt / β-catenin","route":"/pathways/wnt/"}],"term":[{"id":"gene-fusion","kind":"term","name":"Gene fusion","route":"/terms/gene-fusion/"},{"id":"gbrca-mutation","kind":"term","name":"Germline BRCA mutation (gBRCA)","route":"/terms/gbrca-mutation/"},{"id":"tumour-grade","kind":"term","name":"Grade","route":"/terms/tumour-grade/"},{"id":"hrd","kind":"term","name":"Homologous recombination deficiency (HRD)","route":"/terms/hrd/"},{"id":"msi","kind":"term","name":"Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR)","route":"/terms/msi/"},{"id":"neoadjuvant-adjuvant","kind":"term","name":"Neoadjuvant / adjuvant / perioperative","route":"/terms/neoadjuvant-adjuvant/"},{"id":"oligometastatic","kind":"term","name":"Oligometastatic disease","route":"/terms/oligometastatic/"},{"id":"whipple","kind":"term","name":"Whipple procedure (pancreaticoduodenectomy)","route":"/terms/whipple/"}],"person":[{"id":"anirban-maitra","kind":"person","name":"Anirban Maitra","route":"/people/anirban-maitra/"},{"id":"eileen-oreilly","kind":"person","name":"Eileen M. O'Reilly","route":"/people/eileen-oreilly/"},{"id":"richard-schulick","kind":"person","name":"Richard Schulick","route":"/people/richard-schulick/"}]}}