# Pancreatic acinar cell carcinoma

Source: https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/  
OnCo record `pancreatic-acinar-cell-carcinoma` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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.

The 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.

Surgery 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.

## Fields

- Kind: Cancer
- Last checked: 2026-09-18
- Also known as: Acinar cell carcinoma; ACC of the pancreas; Acinar carcinoma; Mixed acinar-neuroendocrine carcinoma
- Tags: subtype-page; gastrointestinal
- 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

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/pancreatic-acinar-cell-carcinoma/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#overview [4 state-of-the-art points]
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#what-it-is [6 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#finding-it [6 biomarkers]
- Treatment (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#treating-it [4 settings, 4 decisions with options]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#evidence [4 key papers, 4 milestones]
- Biology and targets (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#science [5 targets, 4 pathways]
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/where-you-are/
- Decisions and support (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/#living-with-it [16 questions, 6 red cards]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/coming/ [8 medicines, 4 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/pancreatic-acinar-cell-carcinoma/data/ [51 connected records]

## Standard of care

- Diagnosis: Biopsy with acinar markers; CT staging; germline testing and comprehensive tumour sequencing with fusion detection for every patient. ([Endoscopic ultrasound and EBUS systems](https://onco.cc/technologies/endoscopic-ultrasound-systems/), [CT (computed tomography)](https://onco.cc/technologies/ct/), [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/), [Comprehensive genomic profiling](https://onco.cc/technologies/cgp/))
- Resectable: Pancreatoduodenectomy or distal pancreatectomy even for large tumours, with adjuvant chemotherapy by extrapolation from ductal adenocarcinoma, usually a fluoropyrimidine and oxaliplatin regimen. ([Whipple procedure (pancreaticoduodenectomy)](https://onco.cc/terms/whipple/), [FOLFOX (5-FU, leucovorin, oxaliplatin)](https://onco.cc/drugs/folfox/), [FOLFIRINOX / mFOLFIRINOX](https://onco.cc/drugs/folfirinox/), [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/))
- Advanced: FOLFOX or FOLFIRINOX preferred over gemcitabine-based regimens on retrospective evidence; resection of the primary and limited metastases considered after response. ([FOLFOX (5-FU, leucovorin, oxaliplatin)](https://onco.cc/drugs/folfox/), [FOLFIRINOX / mFOLFIRINOX](https://onco.cc/drugs/folfirinox/), [Oxaliplatin](https://onco.cc/drugs/oxaliplatin/), [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/), [Oligometastatic disease](https://onco.cc/terms/oligometastatic/))
- Molecularly selected: MEK inhibition for BRAF fusions on case-series evidence; platinum and PARP inhibitors for homologous recombination defects; pembrolizumab for mismatch repair deficiency. ([Dabrafenib + trametinib](https://onco.cc/drugs/dabrafenib-trametinib/), [Olaparib](https://onco.cc/drugs/olaparib/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Gene fusion](https://onco.cc/terms/gene-fusion/), [Homologous recombination deficiency (HRD)](https://onco.cc/terms/hrd/))

## State of the art

- 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.

## Open problems

- 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.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Acinar_cell_carcinoma_of_the_pancreas
- Wikipedia: https://en.wikipedia.org/wiki/Acinar_cell_carcinoma_of_the_pancreas
- NCCN Guidelines: Pancreatic Adenocarcinoma: https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455

## Connected records

- cancers: [BRCA or PALB2-mutant pancreatic ductal adenocarcinoma](https://onco.cc/cancers/brca-palb2-pdac/), [Intraductal papillary mucinous neoplasm and other pancreatic cystic precursors](https://onco.cc/cancers/ipmn-cystic-precursors/), [KRAS wild-type pancreatic ductal adenocarcinoma](https://onco.cc/cancers/kras-wild-type-pdac/), [Metastatic pancreatic ductal adenocarcinoma](https://onco.cc/cancers/metastatic-pdac/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Pancreatic neuroendocrine tumours](https://onco.cc/cancers/pancreatic-net/), [Pancreatoblastoma](https://onco.cc/cancers/pancreatoblastoma/), [Resectable pancreatic ductal adenocarcinoma](https://onco.cc/cancers/resectable-pdac/), [Solid pseudopapillary neoplasm of the pancreas](https://onco.cc/cancers/solid-pseudopapillary-neoplasm/)
- technologies: [Comprehensive genomic profiling](https://onco.cc/technologies/cgp/), [CT (computed tomography)](https://onco.cc/technologies/ct/), [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [Endoscopic ultrasound and EBUS systems](https://onco.cc/technologies/endoscopic-ultrasound-systems/), [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [PARP inhibitors](https://onco.cc/technologies/parp-inhibitor/), [PDAC organoid pharmacotyping](https://onco.cc/technologies/pdac-organoid-pharmacotyping/), [Robotic & minimally invasive surgery](https://onco.cc/technologies/robotic-surgery/)
- targets: [BRAF](https://onco.cc/targets/braf/), [BRCA1 / BRCA2 (HRD)](https://onco.cc/targets/brca/), [KRAS](https://onco.cc/targets/kras/)
- drugs: [Dabrafenib + trametinib](https://onco.cc/drugs/dabrafenib-trametinib/), [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/), [FOLFIRINOX / mFOLFIRINOX](https://onco.cc/drugs/folfirinox/), [FOLFOX (5-FU, leucovorin, oxaliplatin)](https://onco.cc/drugs/folfox/), [Gemcitabine](https://onco.cc/drugs/gemcitabine/), [Olaparib](https://onco.cc/drugs/olaparib/), [Oxaliplatin](https://onco.cc/drugs/oxaliplatin/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- pathways: [Double-strand break repair: HR versus end joining](https://onco.cc/pathways/homologous-recombination-repair/), [Pancreatic cancer (KEGG map)](https://onco.cc/pathways/pancreatic-cancer-signalling/), [RAS / RAF / MEK / ERK (MAPK)](https://onco.cc/pathways/ras-mapk/), [Wnt / β-catenin](https://onco.cc/pathways/wnt/)
- terms: [Gene fusion](https://onco.cc/terms/gene-fusion/), [Germline BRCA mutation (gBRCA)](https://onco.cc/terms/gbrca-mutation/), [Grade](https://onco.cc/terms/tumour-grade/), [Homologous recombination deficiency (HRD)](https://onco.cc/terms/hrd/), [Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR)](https://onco.cc/terms/msi/), [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/), [Oligometastatic disease](https://onco.cc/terms/oligometastatic/), [Whipple procedure (pancreaticoduodenectomy)](https://onco.cc/terms/whipple/)
- people: [Anirban Maitra](https://onco.cc/people/anirban-maitra/), [Eileen M. O'Reilly](https://onco.cc/people/eileen-oreilly/), [Richard Schulick](https://onco.cc/people/richard-schulick/)
- key papers: [Chmielecki 2014: comprehensive genomic profiling of pancreatic acinar cell carcinomas identifies recurrent RAF fusions and frequent inactivation of DNA repair genes](https://onco.cc/key-papers/paper-chmielecki-acinar-cell-carcinoma-raf-fusions-dna-repair-cancer-discov-2014/), [Klimstra 1992: acinar cell carcinoma of the pancreas, a clinicopathologic study of 28 cases](https://onco.cc/key-papers/paper-klimstra-acinar-cell-carcinoma-pancreas-28-cases-ajsp-1992/), [La Rosa 2012: clinicopathologic study of 62 acinar cell carcinomas of the pancreas](https://onco.cc/key-papers/paper-la-rosa-acinar-cell-carcinoma-62-cases-ajsp-2012/), [Wisnoski 2008: 672 patients with acinar cell carcinoma of the pancreas, a population-based comparison to pancreatic adenocarcinoma](https://onco.cc/key-papers/paper-wisnoski-acinar-cell-carcinoma-672-patients-seer-surgery-2008/)

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JSON: https://onco.cc/api/v1/entities/pancreatic-acinar-cell-carcinoma.json