Objectives To identify the imaging features of pancreatic acinar cell carcinoma (PACC) and to classify them according to morphological subtypes. Materials and methods This multicenter retrospective study included 36 patients with pathologically confirmed PACC who underwent CT/MRI from 2008 to 2024. Tumors were classified into three morphologic subtypes based on imaging features identified in this study: Type 1, well-demarcated solid mass; Type 2, predominantly intraductal mass; Type 3, indistinct infiltrative mass. Maximal tumor size, marked diffusion restriction, lobulated internal architecture, venous thrombosis, and proportion of intratumoral necrosis were evaluated. Differences among subtypes were analyzed using the Kruskal–Wallis test and Fisher’s exact test. In 28 patients who underwent curative resection, Cox regression analysis was performed to identify predictors of recurrence. Results PACC commonly showed marked diffusion restriction (76.7%), lobulated internal architecture (52.8%), and minimal intratumoral necrosis (80.6%). Nineteen tumors were classified as Type 1, eight as Type 2, and nine as Type 3. Type 1 tumors were larger than Type 2 and Type 3 (6.3 cm vs. 3.0 cm vs. 2.5 cm; p = 0.002) and more frequently showed venous thrombosis (31.6% vs. 0% vs. 0%; p = 0.040) and lobulated internal architecture (78.9% vs. 37.5% vs. 11.1%, p = 0.002). On multivariable analysis, maximal tumor size (hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.2–2.3) and Type 3 tumor (HR 7.7, 95% CI 1.1–53.6) were independent predictors of recurrence. Conclusion PACC shows characteristic imaging features and distinct morphologic subtypes. Tumor size and the infiltrative subtype may predict postoperative recurrence. Key Points <Emphasis Type="BoldItalic">Question</Emphasis> Pancreatic acinar cell carcinoma (PACC) is a rare tumor with imaging features overlapping other pancreatic neoplasms, and imaging biomarkers for recurrence risk remain limited. <Emphasis Type="BoldItalic">Findings</Emphasis> PACC showed three morphologic imaging phenotypes, and an indistinct infiltrative subtype and larger tumor size were independently associated with recurrence after curative resection. <Emphasis Type="BoldItalic">Clinical relevance</Emphasis> Recognition of morphologic imaging phenotypes of PACC may help radiologists differentiate PACC from more common pancreatic tumors and identify patients at higher risk of postoperative recurrence. Graphical Abstract

Imaging phenotypes of pancreatic acinar cell carcinoma: a multicenter study of morphologic subtypes and recurrence

期刊论文
发表日期：

2026年7月18日

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Jeong Ah Hwang,
Sunyoung Lee,
Seo-Youn Choi,
Ji Eun Lee,
Jisun Lee

摘要

Objectives

To identify the imaging features of pancreatic acinar cell carcinoma (PACC) and to classify them according to morphological subtypes.

Materials and methods

This multicenter retrospective study included 36 patients with pathologically confirmed PACC who underwent CT/MRI from 2008 to 2024. Tumors were classified into three morphologic subtypes based on imaging features identified in this study: Type 1, well-demarcated solid mass; Type 2, predominantly intraductal mass; Type 3, indistinct infiltrative mass. Maximal tumor size, marked diffusion restriction, lobulated internal architecture, venous thrombosis, and proportion of intratumoral necrosis were evaluated. Differences among subtypes were analyzed using the Kruskal–Wallis test and Fisher’s exact test. In 28 patients who underwent curative resection, Cox regression analysis was performed to identify predictors of recurrence.

Results

PACC commonly showed marked diffusion restriction (76.7%), lobulated internal architecture (52.8%), and minimal intratumoral necrosis (80.6%). Nineteen tumors were classified as Type 1, eight as Type 2, and nine as Type 3. Type 1 tumors were larger than Type 2 and Type 3 (6.3 cm vs. 3.0 cm vs. 2.5 cm; p = 0.002) and more frequently showed venous thrombosis (31.6% vs. 0% vs. 0%; p = 0.040) and lobulated internal architecture (78.9% vs. 37.5% vs. 11.1%, p = 0.002). On multivariable analysis, maximal tumor size (hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.2–2.3) and Type 3 tumor (HR 7.7, 95% CI 1.1–53.6) were independent predictors of recurrence.

Conclusion

PACC shows characteristic imaging features and distinct morphologic subtypes. Tumor size and the infiltrative subtype may predict postoperative recurrence.

Key Points

Question Pancreatic acinar cell carcinoma (PACC) is a rare tumor with imaging features overlapping other pancreatic neoplasms, and imaging biomarkers for recurrence risk remain limited.

Findings PACC showed three morphologic imaging phenotypes, and an indistinct infiltrative subtype and larger tumor size were independently associated with recurrence after curative resection.

Clinical relevance Recognition of morphologic imaging phenotypes of PACC may help radiologists differentiate PACC from more common pancreatic tumors and identify patients at higher risk of postoperative recurrence.

Graphical Abstract