Germline BRCA1-Mutated Synchronous and Metachronous Pancreatic Acinar Cell Carcinoma With Long-Term Survival.

BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic neoplasm. Recently, molecular analysis revealed that PACC shows a high frequency of the BRCA1/2 mutation and is likely to be considered a cancer associated with hereditary breast and ovarian cancer (HBOC). Hereditary cancers, including HBOC, are characterized by multifocal and/or metachronous tumors. However, no case reports exist of germline BRCA1-mutated synchronous and metachronous PACC. CASE: A 58-year-old man was diagnosed with synchronous and metachronous PACC at the age of 56 and underwent two surgeries. Ten months after the second surgery, the patient developed multiple liver metastases. Gemcitabine plus nab-paclitaxel therapy was administered as first-line chemotherapy. After seven cycles, computed tomography examination revealed progressive disease (PD). Therefore, modified FOLFIRINOX (mFFX) was administered as second- line chemotherapy. After 19 cycles of mFFX, comprehensive cancer genomic profiling (CGP) identified a BRCA1 pathogenic variant that was confirmed to be germline origin. Accordingly, we treated the patient with olaparib; however, he was diagnosed with PD after 4 months. He subsequently died 5 years and 9 months after the initial surgery, and 3 years and 10 months after chemotherapy. Based on the genetic data of the patients, his family members received genetic counseling followed by cascade testing. Consequently, the same gBRCA1 pathogenic variant was detected in the son and his surveillance for HBOC-related cancers was initiated. CONCLUSION: We diagnosed a 58-year-old man with a synchronous and metachronous PACC with germline BRCA1 pathogenic variant. Considering that PACC is likely to have BRCA1/2 mutations responsible for HBOC, we need to be aware of the possible presence of multifocal and/or metachronous tumors in patients with PACC. Additionally, patients with PACC should undergo genetic examinations, which would be beneficial in determining treatment strategies and health care for blood relatives.

Liquid-based cytology features of pancreatic acinar cell carcinoma: comparison with other non-ductal neoplasms of the pancreas.

BACKGROUND: Acinar cell carcinoma (ACC) is a rare malignant epithelial neoplasm, which shares many cytomorphological features with other non-ductal pancreatic neoplasms such as pancreatic neuroendocrine neoplasm (PanNEN) and solid-pseudopapillary neoplasm (SPN). Due to the relative rarity of these tumors, pathologists are less familiar with the cytological features, especially on liquid-based cytology (LBC) which has been relatively recently introduced for endoscopic ultrasound-guided fine needle aspiration specimens. METHODS: We evaluated the detailed cytological features of 15 histologically confirmed ACC (7 conventional smears [CS], 8 LBC), and compared them with the LBC features of SPN (n = 9) and PanNEN (n = 9). RESULTS: Compared with CS, LBCs of ACC demonstrated significantly less bloody background. All ACCs demonstrated prominent nucleoli and macronucleoli on LBC. On comparison with the LBC features of SPN and PanNEN, most ACCs demonstrated a necrotic background with apoptotic debris while PanNEN and SPN did not show these features. Acinar structures were predominantly observed in ACC, while frequent pseudopapillary structures were seen only in SPN. Prominent nucleoli and macronucleoli were only seen in ACC. CONCLUSIONS: ACC had characteristic cytological features that could be observed on LBC preparations, such as high cellularity, necrotic/apoptotic background, nuclear tangles, acinar arrangement of cells, and macronucleoli. These findings also help distinguish ACC from PanNEN and SPN on LBC. It is important to be familiar with these features, as an accurate diagnosis on endoscopic ultrasound-guided fine needle aspiration cytology would have impact on the management of the patient.

Successful curative treatment for a ruptured pancreatic acinar cell carcinoma by radical resection following modified FOLFIRINOX: a case report and literature review.

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor type, and ruptured pancreatic tumors are rarer. Computed tomography (CT) in a 48-year-old man incidentally revealed a raptured pancreatic tail tumor. The patient was treated conservatively because he was asymptomatic, and his general condition was stable. After a detailed examination, the pancreatic tumor was diagnosed as raptured PACC. Considering the potential infiltration of tumor cells into the hematoma within the omental sac, our decision is to initiate chemotherapy as the primary course of action. A liquid biopsy was performed, and comprehensive genomic profiling of circulating tumor DNA showed a tumor BRCA2 mutation. Chemotherapy with modified FOLFIRINOX (mFFX) was selected as the first treatment. After seven courses of mFFX, the primary tumor diminished remarkably. At this time, the radical resection was performed via distal pancreatectomy with simultaneous resection of the gastric wall and colon, which had adhered strongly to the tumor. Histopathological examination revealed that the tumor had shrunk to less than 5% of its original size due to chemotherapy (Grade 3 of Evans Classification). Devising treatment strategies for ruptured pancreatic malignant tumors is challenging due to the worsening general condition caused by severe abdominal symptoms and intra-abdominal bleeding. In this context, this case-report documents a rare instance of raptured PACC with a tumor BRCA2 mutation that underwent radical resection following mFFX treatment.

Complete pathological response to pembrolizumab in pretreated pancreatic acinar cell carcinoma.

BACKGROUND: Therapeutic approach used for pancreatic ductal adenocarcinoma is usually translated also for the rarer acinar counterpart, which shows a different mutational landscape nevertheless. While dMMR/MSI-H status is rare in the ductal histotype, it appears to be more prevalent in pancreatic acinar cell carcinoma (PACC). CASE PRESENTATION: We report the case of a patient with locally advanced MSI-H PACC in whom the treatment with the anti-PD-1 pembrolizumab, administered as third line, made possible surgical resection, achieving even an exceptional pathological complete response. CONCLUSIONS: Treatment of PACC should be tailored based on the peculiar molecular features that distinguish PACC from ductal adenocarcinoma. Evaluation of potentially therapeutically targetable alterations should be mandatory in case of PACC diagnosis.

A case of BRCA1-mutated giant pancreatic acinar cell carcinoma successfully treated with modified FOLFIRINOX therapy and radical resection.

Pancreatic acinar cell carcinoma (PACC) is a rare type of pancreatic cancer; further, its pathogenesis and treatment strategies remain unclear. We report the case of a 70-year-old man who presented with a chief complaint of abdominal distention. Computed tomography scans revealed a large lobulated mass (tumor diameter: 150 mm) in the pancreatic body tail, which was diagnosed as a PACC through endoscopic ultrasonography fine needle aspiration. The other imaging modalities did not reveal distant metastases, and the tumor was classified as resectable. Neoadjuvant chemotherapy was planned after staging laparoscopy ruled out microscopic distant metastasis. First-line chemotherapy with gemcitabine + nab-paclitaxel failed due to tumor growth and worsening abdominal distention. Evaluation using the BRACAnalysis® device indicated that the patient was positive for BRCA1 mutation. Second-line modified FOLFIRINOX (mFFX) resulted in a marked decrease in elastase 1 levels; moreover, a partial antitumor response was observed, which prompted radical resection. After distal pancreatectomy, the patient has survived for 3.5 years without recurrence. BRCA-mutated pancreatic cancer is more likely to respond to mFFX, including platinum, and BRCA mutations have been reported to be highly prevalent in PACC. It is important to evaluate the presence of BRCA mutations in patients with PACC prior to treatment.

Paediatric pancreatic acinar cell carcinoma with a novel SEC31A-BRAF fusion gene.

Paediatric pancreatic acinar cell carcinoma (PACC) presents a diagnostic challenge, often confused with pancreatoblastoma (PB) due to its rarity. It is crucial to differentiate between PB and PACC, given their distinct therapeutic strategies and prognoses. Histologically, the absence of squamoid nests and scarcity of tumor mesenchyme support PACC. Conversely, the identification of a BRAF alteration leans towards PACC. Here, we present the case of an 8-year-old girl with a well-defined mass in the pancreas. The tumor exhibited a SEC31A-BRAF fusion gene and amplification of 18p, showcasing unequivocal acinar differentiation and a minor degree of neuroendocrine differentiation. Additionally, the tumor displayed scant fibrous stroma, and an absence of squamoid nests, further supporting PACC. Notably, this is the first reported instance of a solid tumor featuring a SEC31A-BRAF gene fusion. The discovery of this novel fusion gene expands our understanding of BRAF fusion partner profiles, particularly in the context of paediatric PACC.

The response of pancreatic acinar cell carcinoma to platinum and olaparib therapy in a germline BRCA2 variant carrier: case report and literature review.

A 73-year-old Japanese man with a history of distal biliary cancer treated by pancreatoduodenectomy developed pancreatic acinar cell carcinoma (PACC) treated by remnant pancreatectomy and adjuvant chemotherapy. Thirteen months after surgery, multiple liver metastases developed and FOLFOX chemotherapy was initiated. Based on the PACC diagnosis and a positive family history for breast and ovarian cancer genetic testing was performed which revealed a pathogenic germline BRCA2 variant (c.8629G > T, p.Glu2877Ter). Olaparib therapy was initiated and the metastases responded well (partial response). PACC is a BRCA2-associated cancer which may respond well to PARP inhibitors.

Pathological complete response with FOLFIRINOX therapy for recurrence of pancreatic acinar cell carcinoma.

Pancreatic acinar cell carcinoma (PACC) is a very rare subtype of pancreatic cancer. Due to small number of patients, no standard chemotherapy protocol has been established. We experienced an extremely rare case of PACC with liver metastasis that showed a pathological complete response after modified FOLFIRINOX (mFFX) therapy. A 42-year-old man who underwent distal pancreatectomy for an 80 mm tumor at the pancreatic tail 3 years ago was referred to our hospital in September 2017 for the treatment of a recurrent liver tumor. Percutaneous biopsy revealed an acinar-neuroendocrine carcinoma, similar to the surgical specimen. He received eight cycles of irinotecan plus cisplatin chemotherapy. However, the tumor increased in size, and treatment was switched to mFFX therapy. The tumor in the liver shrank remarkably after nine cycles of mFFX therapy. Conversion surgery was selected, and the patient underwent hepatic left and caudate lobectomy 8 months after administration of mFFX. The resected specimen showed no viable tumor cells, indicating a pathological complete response. The histological diagnosis was reconsidered, and PACC was finally diagnosed via an additional immunohistological review. The patient has remained well with no recurrence for 6 years after surgery. This study is the first to report a case of pathological complete response with mFFX therapy for the recurrence of PACC.

A case of acinar cell carcinoma originating from the accessory papilla of the duodenum.

CASE PRESENTATION: A 61-year-old female was referred to our hospital with a neoplastic lesion in the duodenum. Computed tomography with contrast enhancement revealed a 10-mm tumor in the duodenum. Upper gastrointestinal endoscopy revealed a submucosal tumor-like lesion in the descending part of the duodenum. Endoscopic ultrasound revealed a well-defined hypoechoic tumor. Biopsy and immunohistochemical findings including negative Synaptophysin and Chromogranin A staining and positive Trypsin and BCL10 staining suggested a carcinoma with acinar cell differentiation. Pancreatoduodenectomy was performed, and the resected specimen had a 15-mm solid nodule in the submucosal layer of the duodenum. Pancreatogram of the resected specimen revealed a tumor localized in the accessory papilla region. In histopathological examination, the tumor was found in the submucosa of the duodenum with pancreatic tissue present nearby, and these were separated from the pancreatic parenchyma by the duodenal muscle layer. These findings led to a diagnosis of acinar cell carcinoma originating from the accessory papilla of the duodenum. CONCLUSION: Acinar cell carcinoma originating from the accessory papilla of the duodenum is exceptionally rare, with no reported cases to date. The origin was considered to be pancreatic tissue located in the accessory papilla region.

DNA Methylation Profiling Enables Accurate Classification of Nonductal Primary Pancreatic Neoplasms.

BACKGROUND & AIMS: Cytologic and histopathologic diagnosis of non-ductal pancreatic neoplasms can be challenging in daily clinical practice, whereas it is crucial for therapy and prognosis. The cancer methylome is successfully used as a diagnostic tool in other cancer entities. Here, we investigate if methylation profiling can improve the diagnostic work-up of pancreatic neoplasms. METHODS: DNA methylation data were obtained for 301 primary tumors spanning 6 primary pancreatic neoplasms and 20 normal pancreas controls. Neural Network, Random Forest, and extreme gradient boosting machine learning models were trained to distinguish between tumor types. Methylation data of 29 nonpancreatic neoplasms (n = 3708) were used to develop an algorithm capable of detecting neoplasms of non-pancreatic origin. RESULTS: After benchmarking 3 state-of-the-art machine learning models, the random forest model emerged as the best classifier with 96.9% accuracy. All classifications received a probability score reflecting the confidence of the prediction. Increasing the score threshold improved the random forest classifier performance up to 100% with 87% of samples with scores surpassing the cutoff. Using a logistic regression model, detection of nonpancreatic neoplasms achieved an area under the curve of >0.99. Analysis of biopsy specimens showed concordant classification with their paired resection sample. CONCLUSIONS: Pancreatic neoplasms can be classified with high accuracy based on DNA methylation signatures. Additionally, non-pancreatic neoplasms are identified with near perfect precision. In summary, methylation profiling can serve as a valuable adjunct in the diagnosis of pancreatic neoplasms with minimal risk for misdiagnosis, even in the pre-operative setting.

Long-term safety and efficacy outcomes of valoctocogene roxaparvovec gene transfer up to 6 years post-treatment.

INTRODUCTION: Valoctocogene roxaparvovec uses an adeno-associated virus serotype 5 (AAV5) vector to transfer a factor VIII (FVIII) coding sequence to individuals with severe haemophilia A, providing bleeding protection. AIM: To assess safety and efficacy of valoctocogene roxaparvovec 5-6 years post-treatment. METHODS: In a phase 1/2 trial, adult male participants with severe haemophilia A (FVIII ≤1 IU/dL) without FVIII inhibitors or anti-AAV5 antibodies received valoctocogene roxaparvovec and were followed for 6 (6 × 1013 vg/kg; n = 7) and 5 (4 × 1013 vg/kg; n = 6) years. Safety, including investigation of potential associations between a malignancy and gene therapy, and efficacy are reported. RESULTS: No new treatment-related safety signals emerged. During year 6, a participant in the 6 × 1013  vg/kg cohort was diagnosed with grade 2 parotid gland acinar cell carcinoma; definitive treatment was uncomplicated parotidectomy with lymph node dissection. Target enrichment sequencing of tumour and adjacent healthy tissue revealed low vector integration (8.25 × 10-5 per diploid cell). Integrations were not elevated in tumour samples, no insertions appeared to drive tumorigenesis, and no clonal expansion of integration-containing cells occurred. During all follow-ups, >90% decreases from baseline in annualised treated bleeds and FVIII infusion rates were maintained. At the end of years 6 and 5, mean FVIII activity (chromogenic assay) was 9.8 IU/dL (median, 5.6 IU/dL) and 7.6 IU/dL (median, 7.1 IU/dL) for the 6 × 1013 and 4 × 1013 vg/kg cohorts, respectively, representing proportionally smaller year-over-year declines than earlier timepoints. CONCLUSIONS: Valoctocogene roxaparvovec safety and efficacy profiles remain largely unchanged; genomic investigations showed no association with a parotid tumour.

Referral and treatment patterns in pancreatic acinar cell carcinoma: A regional population-level analysis.

BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare exocrine tumor of the pancreas. We evaluated the effect disease stage, surgical intervention, and institutional volume status plays in survival. METHODS: We queried the Oregon State Cancer Registry for patients with PACC from 1997 to 2018. Treatment and referral patterns were analyzed, and overall survival (OS) was evaluated with Kaplan-Meier and Cox-proportional hazard analysis. RESULTS: 43 patients were identified. Median OS was 33.1 and 7.1 months in those with locoregional and metastatic disease respectively (p â€‹= â€‹0.008). Surgical intervention was associated with improved OS (hazard ratio 0.28, p â€‹< â€‹0.0001). High volume center (HVC) care trended towards improving OS. While the majority of cases were diagnosed at low volume centers (74%), referral to HVCs was rare (n â€‹= â€‹4) and limited to advanced (stage III/IV) disease. CONCLUSION: Stage and surgical resection influence survival outcomes in PACC, more data is needed to delineate the impact of institutional volume status.

[Exocrine meets neuroendocrine: mimickers of pancreatic neuroendocrine neoplasms]. / Exokrin trifft neuroendokrin: Mimickers neuroendokriner Neoplasien des Pankreas.

Neuroendocrine neoplasms (NENs) originate from various epithelial or neuroectodermal tissues, can occur in any organ, including the pancreas, and are characterized by the expression of the neuroendocrine markers synaptophysin and chromogranin A. Pancreatic neuroendocrine tumors (PanNETs) are well-differentiated epithelial neoplasms with morphological and immunohistochemical features of neuroendocrine differentiation of low, intermediate, or high grade. Pancreatic neuroendocrine carcinomas (PanNECs) are clinically aggressive, high-grade (poorly differentiated) carcinomas with morphologic features suggesting neuroendocrine differentiation, a high proliferative rate (> 20 mitoses per 2 mm2 and Ki67 index > 20%), and immunohistochemical labeling for neuroendocrine markers. They include the small cell neuroendocrine carcinoma and the large cell neuroendocrine carcinoma categories.Neuroendocrine-like morphology coupled with immunohistochemical markers of neuroendocrine differentiation are highly specific. However, neuroendocrine markers may also be expressed in non-neuroendocrine neoplasms, which can therefore be confused with NENs. Mimickers of pancreatic NENs comprise a number of important pitfall tumors, including epithelial and non-epithelial neoplasms, such as acinar cell carcinomas, solid pseudopapillary neoplasms (SPNs), or even non-neoplastic lesions. All of these lesions have the expression of neuroendocrine markers in common, such as synaptophysin and chromogranin A, and although they are comparatively rare, they can cause considerable diagnostic problems. This review article deals with some of the most important mimickers of pancreatic neuroendocrine neoplasms and even non-neoplastic lesions, such as islet aggregation. The similarities and differences between these entities and pancreatic neuroendocrine neoplasms are highlighted, and key findings that facilitate the correct diagnosis are discussed.

Single-cell mapping identifies MSI+ cells as a common origin for diverse subtypes of pancreatic cancer.

Identifying the cells from which cancers arise is critical for understanding the molecular underpinnings of tumor evolution. To determine whether stem/progenitor cells can serve as cells of origin, we created a Msi2-CreERT2 knock-in mouse. When crossed to CAG-LSL-MycT58A mice, Msi2-CreERT2 mice developed multiple pancreatic cancer subtypes: ductal, acinar, adenosquamous, and rare anaplastic tumors. Combining single-cell genomics with computational analysis of developmental states and lineage trajectories, we demonstrate that MYC preferentially triggers transformation of the most immature MSI2+ pancreas cells into multi-lineage pre-cancer cells. These pre-cancer cells subsequently diverge to establish pancreatic cancer subtypes by activating distinct transcriptional programs and large-scale genomic changes, and enforced expression of specific signals like Ras can redirect subtype specification. This study shows that multiple pancreatic cancer subtypes can arise from a common pool of MSI2+ cells and provides a powerful model to understand and control the programs that shape divergent fates in pancreatic cancer.

Rare ROS1-CENPW gene in pancreatic acinar cell carcinoma and the effect of crizotinib plus AG chemotherapy: A case report.

BACKGROUND: This is the first report of an ROS1-CENPW fusion gene in pancreatic malignancies. CASE SUMMARY: A 77-year-old woman with a pancreatic tumor and multiple liver metastases was admitted to our hospital. Genetic testing revealed the presence of the ROS1-CENPW fusion gene, a rare fusion gene that has not been previously reported in the field of pancreatic cancer. The patient received crizotinib plus AG (albumin paclitaxel plus gemcitabine) chemotherapy. After treatment, the patient's condition stabilized, and her prognosis was good. CONCLUSION: The ROS1-CENPW gene treatment regimen used in this case is an excellent treatment option that provides new hope for patients with advanced pancreatic cancer and similar genetic mutations. To date, owing to the rarity of the ROS1-CENPW fusion gene, our team has encountered only a single case. Therefore, the efficacy of crizotinib plus AG chemotherapy in patients with pancreatic acinar cell carcinoma harboring the ROS1-CENPW fusion gene requires further validation.

Two rare cancers of the exocrine pancreas: to treat or not to treat like ductal adenocarcinoma?

Pancreatic cancer is an aggressive malignancy with increasing incidence. Pancreatic ductal adenocarcinoma (PDAC) accounts for > 90% of pancreatic cancer diagnoses, while other exocrine tumors are much rarer. In this review, we have focused on two rare cancers of the exocrine pancreas: adenosquamous carcinoma of the pancreas (ASCP) and pancreatic acinar cell carcinoma (PACC). The latest findings regarding their cellular and molecular pathology, clinical characteristics, prognosis, and clinical management are discussed. New genetic and transcriptomic data suggest that ASCP is related to or overlaps with the basal transcriptomic subtype of PDAC. These tumors are highly aggressive and driven by activated KRAS and MYC expression. Clinical outcomes remain poor and effective treatments are limited. PACC has no morphologic or genetic resemblance to PDAC and more favorable outcomes. Early stage PACC patients have improved survival with surgical resection and patients with advanced disease benefit most from platinum- or fluoropyrimidine-containing chemotherapy. Frequency of actionable genetic mutations is high in this disease and case reports suggest good outcomes when matched therapy is given. Dedicated clinical studies examining ASCP and PACC are limited and difficult to accrue. Further research is needed to define optimal clinical management for these rare diseases.

A resected case of acinar cell carcinoma of the pancreas with liver metastasis following chemotherapy using modified FOLFIRINOX.

BACKGROUND: Acinar cell carcinoma of the pancreas is a rare exocrine malignancy representing less than 1% of all pancreatic neoplasms. It has been reported that it responds to treatment differently from pancreatic ductal adenocarcinoma and the treatment algorithm for acinar cell carcinoma usually depends on the stage of the respective tumor and the patient's current status. CASE PRESENTATION: A 60-year-old man presented with upper abdominal pain and anorexia. Abdominal ultrasonography showed a large-sized hepatic mass and he was referred to our hospital. Contrast-enhanced computed tomography demonstrated a 110-mm low-density area occupying the right hemi-liver and an enhanced mass of 70 × 56 mm in the tail of the pancreas, which seemed to directly infiltrate into the spleen. The case was diagnosed as acinar cell carcinoma with a simultaneous liver metastasis identified by liver biopsy. Upfront resection of pancreatic cancer with distant metastasis might not be considered as an optimal choice, and in this case chemotherapy was administered prior to curative resection. Chemotherapy using the modified FOLFIRINOX regimen was undertaken, resulting in a partial remission; the liver tumor reduced in size from 110 to 47 mm and the pancreatic tumor from 70 to 40 mm. The patient then safely underwent curative hepatic resection with distal pancreato-splenectomy. Histological examinations revealed small-sized atypical cells with large nuclei that had formed acinar patterns, and immunostaining with trypsin was positive in tumor cells, which was in accordance with acinar cell carcinoma. More than 3 years later, the patient is doing well without any recurrence. CONCLUSION: Aggressive and curative surgery in combination with chemotherapy such as FOLFIRINOX could be a treatment option to achieve long-term survival in cases of acinar cell carcinoma with liver metastases.

New treatment insights into pancreatic acinar cell carcinoma: case report and literature review.

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic malignancy with unique clinical, molecular, and morphologic features. The long-term survival of patients with PACC is substantially better than that of patients with ductal adenocarcinoma of the pancreas. Surgical resection is considered the first choice for treatment; however, there is no standard treatment option for patients with inoperable disease. The patient with metastatic PACC reported herein survived for more than 5 years with various treatments including chemotherapy, radiotherapy, antiangiogenic therapy and combined immunotherapy.

Cytomorphologic, immunophenotypical and molecular features of pancreatic acinar cell carcinoma.

OBJECTIVES: As a rare tumor in pancreas, pancreatic acinar cell carcinoma (PACC) possesses a distinct molecular feature from pancreatic ductal carcinoma (PDAC). Though the diagnosis of PACC is often established based on cytology specimens, its cytologic diagnosis can be challenging. Furthermore, the correlation between PACC cytomorphology and its unique different molecular alterations have not been fully explored. METHODS: Cytology features were analyzed in 8 histologically proven PACC and cytohistological correlation was performed. Immunocytochemistry for trypsin, chymotrypsin, BCL10, synaptophysin, chromogranin A, INSM1, ß-catenin, and Ki-67 was assessed. Comprehensive molecular profiling and additional targetable treatment biomarker assessment were also performed. RESULTS: The cohort included 4 mixed acinar-neuroendocrine carcinomas, 3 pure PACCs, and 1 mixed acinar-ductal carcinoma. Immunophenotypical features are consistent with diagnoses of PACC or PACC with neuroendocrine features. Identified genetic alterations included somatic mutations of CTNNB1, TP53, MAP2K1, PTEN, RAC1, germline mutations of NBN and BRAC2, and gene fusion of CCDC6-RET. CONCLUSIONS: The current study is the first attempt to explore the correlation between the cytomorphology characteristics and molecular features of PACC and a few intriguing findings were observed. Further validation in larger cohorts is warranted.

Pancreatic acinar cell carcinoma with pleomorphic and spindle cells: An autopsy-proven case.

Pancreatic acinar cell carcinomas are glandular and have amphophilic/eosinophilic cytoplasm, presenting acinar, solid, and trabecular structures. Unusual histological features of acinar cell carcinoma are known, such as oncocytic, pleomorphic, spindle, and clear cell variants, but their clinical significance has not been well described. A man in his 70s was referred to our hospital because of elevated serum pancreatic enzymes. Contrast-enhanced abdominal computed tomography revealed slight swelling of the pancreatic head and suspension of the main pancreatic duct in the pancreatic body. He died only 14 days after admission. Gross findings at autopsy showed an ill-defined tumor located in the pancreatic head, involving the gastric and duodenal walls. Peritoneal dissemination, liver metastases, and lymph node metastases were also observed. Microscopically, tumor cells had moderate-to-severe nuclear atypia and amphophilic cytoplasm showing pleomorphism, and diffusely proliferated in solid pattern without lumina, were admixed with spindle cells. Immunohistochemically, tumor cells including pleomorphic and spindle cells were positive for B-cell lymphoma/leukemia 10 and trypsin. Consequently, the diagnosis was pancreatic acinar cell carcinoma with pleomorphic and spindle cells. We encountered a rare variant of pancreatic acinar cell carcinoma with pleomorphic and spindle cells. Clinically, our case showed rapid progression.