Acinar cell carcinoma of the pancreas: a rare disease with different diagnostic and therapeutic implications than ductal adenocarcinoma

A narrative review on rare types of pancreatic cancer: should they be treated as pancreatic ductal adenocarcinomas?

Pancreatic cancer is one of the deadliest malignancies in humans and it is expected to play a bigger part in cancer burden in the years to come. Pancreatic ductal adenocarcinoma (PDAC) represents 85% of all primary pancreatic malignancies. Recently, much attention has been given to PDAC, with significant advances in the understanding of the mechanisms underpinning disease initiation and progression, along with noticeable improvements in overall survival in both localized and metastatic settings. However, given their rarity, rare histological subtypes of pancreatic cancer have been underappreciated and are frequently treated as PDAC, even though they might present non-overlapping molecular alterations and clinical behavior. While some of these rare histological subtypes are true variants of PDAC that should be treated likewise, others represent separate clinicopathological entities, warranting a different therapeutic approach. In this review, we highlight clinical, pathological, and molecular aspects of rare histological types of pancreatic cancer, along with the currently available data to guide treatment decisions.

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.

Exceptional Response of BRAFV600E-Mutated Acinar Cell CUP to BRAF/MEK Inhibition

Complete remission of BRAF V600E-driven ACC CUP by BRAF/MEK inhibition underscores importance of precision oncology.

Comprehensive review of pancreatic acinar cell carcinoma: epidemiology, diagnosis, molecular features and treatment

Pancreatic acinar cell carcinoma is a rare form (0.2-4.3%) of pancreatic neoplasm with unique clinical and molecular characteristics, which largely differ from pancreatic ductal adenocarcinoma. Pancreatic acinar cell carcinoma occurs more frequently in males and can occur in children. Serum lipase is elevated in 24-58% of patients with pancreatic acinar cell carcinoma. Pancreatic acinar cell carcinomas tend to be large at diagnosis (median tumour size: ~5 cm) and are frequently located in the pancreas head. Radiologically, pancreatic acinar cell carcinoma generally exhibits a solid appearance; however, necrosis, cystic changes and intratumoral haemorrhage can occur in larger lesions. Immunostaining is essential for the definitive diagnosis of pancreatic acinar cell carcinoma. Compared with pancreatic ductal adenocarcinoma, pancreatic acinar cell carcinoma has a more favourable prognosis. Although radical surgery is recommended for patients with pancreatic acinar cell carcinoma who do not have distant metastases, the recurrence rate is high. The effectiveness of adjuvant therapy for pancreatic acinar cell carcinoma is unclear. The response to FOLFIRINOX is generally favourable, and some patients achieve a complete response. Pancreatic acinar cell carcinoma has a different genomic profile compared with pancreatic ductal adenocarcinoma. Although genomic analyses have shown that pancreatic acinar cell carcinoma rarely has KRAS, TP53 and CDKN2A mutations, it has a higher prevalence of homologous recombination-related genes, including BRCA1/2 and ATM, than pancreatic ductal adenocarcinoma, suggesting high sensitivity to platinum-containing regimens and PARP inhibitors. Targeted therapies for genomic alternations are beneficial. Therefore, genetic testing is important for patients with pancreatic acinar cell carcinoma to choose the optimal therapeutic strategy.

Genomic Profiling Reveals Germline Predisposition and Homologous Recombination Deficiency in Pancreatic Acinar Cell Carcinoma

PURPOSE

To determine the genetic predisposition underlying pancreatic acinar cell carcinoma (PACC) and characterize its genomic features.

METHODS

Both somatic and germline analyses were performed using an Food and Drug Administration-authorized matched tumor/normal sequencing assay on a clinical cohort of 28,780 patients with cancer, 49 of whom were diagnosed with PACC. For a subset of PACCs, whole-genome sequencing (WGS; n = 12) and RNA sequencing (n = 6) were performed.

RESULTS

Eighteen of 49 (36.7%) PACCs harbored germline pathogenic variants in homologous recombination (HR) and DNA damage response (DDR) genes, including BRCA1 (n = 1), BRCA2 (n = 12), PALB2 (n = 2), ATM (n = 2), and CHEK2 (n = 1). Thirty-one PACCs displayed pure, and 18 PACCs harbored mixed acinar cell histology. Fifteen of 31 (48%) pure PACCs harbored a germline pathogenic variant affecting HR-/DDR-related genes. BRCA2 germline pathogenic variants (11 of 31, 35%) were significantly more frequent in pure PACCs than in pancreatic adenocarcinoma (86 of 2,739, 3.1%; P < .001), high-grade serous ovarian carcinoma (67 of 1,318, 5.1%; P < .001), prostate cancer (116 of 3,401, 3.4%; P < .001), and breast cancer (79 of 3,196, 2.5%; P < .001). Genomic features of HR deficiency (HRD) were detected in 7 of 12 PACCs undergoing WGS, including 100% (n = 6) of PACCs with germline HR-related pathogenic mutations and 1 of 6 PACCs lacking known pathogenic alterations in HR-related genes. Exploratory analyses revealed that in PACCs, the repertoire of somatic driver genetic alterations and the load of neoantigens with high binding affinity varied according to the presence of germline pathogenic alterations affecting HR-/DDR-related genes and/or HRD.

CONCLUSION

In a large pan-cancer cohort, PACC was identified as the cancer type with the highest prevalence of both BRCA2 germline pathogenic variants and genomic features of HRD, suggesting that PACC should be considered as part of the spectrum of BRCA-related malignancies.

Treatment characteristics and outcomes of pure Acinar cell carcinoma of the pancreas - A multicentric European study on radically resected patients

BACKGROUND

Acinar cell carcinomas (ACC) belong to the exocrine pancreatic malignancies. Due to their rarity, there is no consensus regarding treatment strategies for resectable ACC.

METHODS

This is a retrospective multicentric study of radically resected pure pancreatic ACC. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Further endpoints were oncologic outcomes related to tumor stage and therapeutic protocols.

RESULTS

59 patients (44 men) with a median age of 64 years were included. The median tumor size was 45.0 mm. 61.0% were pT3 (n = 36), nodal positivity rate was 37.3% (n = 22), and synchronous distant metastases were present in 10.1% of the patients (n = 6). 5-Years OS was 60.9% and median DFS 30 months. 24 out of 31 recurred systemically (n = 18 only systemic, n = 6 local and systemic). Regarding TNM-staging, only the N2-stage negatively influenced OS and DFS (p = 0.004, p = 0.001). Adjuvant treatment protocols (performed in 62.7%) did neither improve OS (p = 0.542) nor DFS (p = 0.159). In 9 cases, radical resection was achieved following neoadjuvant therapy.

DISCUSSION

Radical surgery is currently the mainstay for resectable ACC, even for limited metastatic disease. Novel (neo)adjuvant treatment strategies are needed, since current systemic therapies do not result in a clear survival benefit in the perioperative setting.

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.

Pancreatic acinar cell carcinoma: A comprehensive review

Acinar cell carcinoma (ACC) is a rare pancreatic malignancy with distinctive clinical, molecular, and morphological features. The long-term survival of ACC patients is substantially superior to that of pancreatic adenocarcinoma patients. As there are no significant patient series about ACCs, our understanding of this illness is mainly based on case reports and limited patient series. Surgical resection is the treatment of choice for patients with the disease restricted to one organ; however, with recent breakthroughs in precision medicine, medicines targeting the one-of-a-kind molecular profile of ACC are on the horizon. There are no standard treatment protocols available for people in which a total surgical resection to cure the condition is not possible. As a result of shared genetic alterations, ACCs are chemosensitive to agents with activity against pancreatic adenocarcinomas and colorectal carcinomas. The role of neoadjuvant or adjuvant chemoradiotherapy has not been established. This article aims to do a comprehensive literature study and present the most recent information on acinar cell cancer.

Clinical characteristic and pathogenesis of tumor-induced acute pancreatitis: a predictive model

Background

The aim of our study was to investigate the clinical characteristics and pathogenesis of tumor-induced acute pancreatitis (AP), and to develop a reliable prediction model of the clinical features to guide the diagnosis and treatment.

Methods

Patients with AP between January 2013 and December 2021 were enrolled in the study and were subdivided into the tumor group and the non-tumor group. The tumor group was subdivided into three groups based on the primary sites. Characteristic parameters, laboratory and imaging results were compared between groups. Least absolute shrinkage and selection operator regression model, XGBoost and random forest model were used to select the predictors associated with tumor-induced AP. Logistic regression analysis was used to validate the performance of the selected predictors and a nomogram was established to provide individualized probability of a tumor origin for AP.

Results

A total amount of 8970 patients were admitted for AP during the study period, and 8637 AP patients were enrolled in the study. Of these, 100 cases (1.16%) were tumor-induced AP. The tumor group was significantly older than the non-tumor group (t = 6.050, p = 0.000). Mild AP was observed in 90 cases, moderate AP in 9 cases and severe AP in one case. Tumors respectively originated from distal bile duct (14 cases), ampulla (13 cases) and pancreas (73 cases). The median time from initial AP to tumor diagnosis was 8.57 weeks and the median number of episode was 2 in the tumor group, which significantly surpassed the non-tumor group (p = 0.000). Age, white blood cell count, percentage of neutrophils, pancreatic or bile duct dilation and recurrent attacks were selected independent predictors for tumor origin. A nomogram model based on these factors was established.

Conclusion

For patients with agnogenic AP, elderly man, recurrent attacks, pancreatic or bile duct dilatation and continuous no significant increase of inflammatory markers prompt to further screening of pancreatic biliary and ampulla.

Optimizing Chemotherapy of Pancreatic Acinar Cell Carcinoma: Our Experiences and Pooled Analysis of Literature

Background:

Pancreatic acinar cell carcinoma (PACC) is rare, and its appropriate treatment remains unknown. We aim to explore the characteristics and optimal treatment of it.

Methods:

The data on clinicopathologic characteristics, molecular alteration, treatment, and survival of patients diagnosed with PACC at the Sun Yat-sen University Cancer Center from 2005 to 2020 were collected. The optimal treatment was explored by co-analyzing our results and published literatures.

Results:

Twenty-two PACC patients were enrolled. Eight of 17 non-metastatic patients received adjuvant chemotherapy. The patients receiving fluoropyrimidine-based regimen (n = 3) had a better median disease-free survival (mDFS) than those with gemcitabine-based regimen (n = 5) (unreached vs 27 months). Eight metastatic patients received first-line chemotherapy. Four patients received second-line chemotherapy. The objective response rate (ORR) of the fluoropyrimidine-based regimen was 85.7% (6/7), much better than that of the gemcitabine-based regimen (0/5). One patient who had responded to the first-line FOLFIRINOX (5-fluorouracil + oxaliplatin + leucovorin + irinotecan) regimen received olaparib as maintenance treatment for 5 months with good tolerance. Thirty-one published literatures, with a total of 86 cases, were included in the co-analysis. The ORR of the first-line fluoropyrimidine-based regimen (n = 47) was higher than that of gemcitabine-based regimen (n = 39) (59.6% vs 15.3%, P < .001). Eight of 11 patients treated with the FOLFIRINOX regimen achieved partial response (PR).

Conclusions:

For patients with metastasis, a fluorouracil-based regimen such as FOLFIRINOX may be preferred, and maintenance treatment of poly ADP-ribose polymerase (PARP) inhibitors after effective platinum-containing treatment for breast cancer susceptibility gene (BRCA) mutation patients must be assessed.

Survival Outcome and Prognostic Factors for Pancreatic Acinar Cell Carcinoma: Retrospective Analysis from the German Cancer Registry Group

Simple Summary

Less than 1% of all pancreatic malignancies are acinar cell carcinomas. Based on data from the German Cancer Registry Group, we performed a comparative analysis of characteristics and prognostic factors of pancreatic acinar cell carcinoma and the most common type of pancreatic cancer—pancreatic ductal adenocarcinoma. Compared to pancreatic ductal adenocarcinoma, patients with pancreatic acinar cell carcinoma were younger at the time of diagnosis and the percentage of males was higher. The prognosis of patients with pancreatic acinar carcinoma was better than that of patients with pancreatic ductal adenocarcinoma. Surgical resection was the strongest positive prognostic factor for pancreatic acinar cell carcinoma. The study shows that pancreatic acinar cell carcinoma has features distinct from pancreatic ductal adenocarcinoma. Radical resection should be advocated, whenever feasible.

Abstract

Background: Pancreatic acinar cell carcinoma (PACC) is a distinct type of pancreatic cancer with low prevalence. We aimed to analyze prognostic factors and survival outcome for PACC in comparison to pancreatic ductal adenocarcinoma (PDAC), based on data from the German Cancer Registry Group. Methods: Patients with PACC and PDAC were extracted from pooled data of the German clinical cancer registries (years 2000 to 2019). The distribution of demographic parameters, tumor stage and therapy modes were compared between PACC and PDAC. The Kaplan–Meier method and Cox regression analysis were used to delineate prognostic factors for PACC. Propensity score matching was used to compare survival between PACC and PDAC. Results: There were 233 (0.44%) patients with PACC out of 52,518 patients with pancreatic malignancy. Compared to PDAC, patients with PACC were younger (median age 66 versus 70, respectively, p < 0.001) and the percentage of males was higher (66.1% versus 53.3%, respectively, p < 0.001). More patients were resected with PACC than with PDAC (56.2% versus 38.9%, respectively, p < 0.001). The estimated overall median survival in PACC was 22 months (95% confidence interval 15 to 27), compared to 12 months (95% confidence interval 10 to 13) in the matched PDAC cohort (p < 0.001). Surgical resection was the strongest positive prognostic factor for PACC after adjusting for sex, age, and distant metastases (hazard ratio 0.34, 95% confidence interval 0.22 to 0.51, p < 0.001). There was no survival benefit for adjuvant therapy in PACC. Conclusions: PACC has overall better prognosis than PDAC. Surgical resection is the best therapeutic strategy for PACC and should be advocated even in advanced tumor stages.

Metastatic Acinar Cell Carcinoma of the Pancreas: A Retrospective Cohort Study on Systemic Chemotherapy and Review of the Literature

OBJECTIVES

Acinar cell carcinoma of the pancreas (pACC) forms a rare subgroup of pancreatic tumors. We report on our institutional experience with systemic first- and further-line therapy in patients with metastatic pACC and embed our findings in a review of the literature.

METHODS

Patients with stage IV pACC who started systemic treatment between 2008 and 2019 at our institution were identified via our institutional database. Clinical data were extracted from the patients' electronic data records. Survival times were calculated by the Kaplan-Meier method.

RESULTS

Six patients received a fluoropyrimidine- and oxaliplatin-containing first-line treatment, and 4 patients were started on gemcitabine-based protocols. Median progression-free survival was 4.8 months [95% confidence interval (CI), 3.3 to not available (n.a.)], and median overall survival was 15.3 months (95% CI, 10.1 to n.a.). Residual survival for second-line treatment was 2.1 months (95% CI, 1.3 to n.a.), although 1 patient experienced almost complete remission under targeted therapy.

CONCLUSIONS

The most encouraging and deep responses result from poly-chemotherapy with leucovorin, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX), which seems to be the appropriate choice in fit patients. Gemcitabine monotherapy seems without substantial activity in pACC. Whenever possible, patients with pACC should be screened for targetable mutations.

Multicenter Retrospective Analysis of Chemotherapy for Advanced Pancreatic Acinar Cell Carcinoma: Potential Efficacy of Platinum- and Irinotecan-Containing Regimens

OBJECTIVES

The aim of this multicenter retrospective study was to identify the optimal chemotherapeutic regimen for advanced pancreatic acinar cell carcinoma (PACC).

METHODS

Fifty-eight patients with histopathologically confirmed advanced PACC who had received chemotherapy between 1996 and 2013 were enrolled. The clinical characteristics of the patients and the treatment efficacy data were collected from the medical records at 16 Japanese institutions, using standardized data collection instrument.

RESULTS

The most commonly selected treatment regimens were gemcitabine-, fluoropyrimidine-, platinum-, and irinotecan-containing regimens. The overall response rate in the patients who received first-line chemotherapy were 7% and 38%, respectively, and the median overall survival was 13.2 months. When the data for all the treatment lines were aggregated, the response rates to gemcitabine-, fluoropyrimidine-, platinum-, and irinotecan-containing regimens were 7%, 18%, 40%, and 29%, respectively. The overall survival tended to be better in patients who had received a platinum-containing regimen (hazard ratio, 0.50; 95% confidence interval, 0.23-1.11; P = 0.08) or irinotecan-containing regimen (hazard ratio, 0.42; 95% confidence interval, 0.15-1.19; P = 0.09) at least once in the treatment course as compared with those who had not.

CONCLUSIONS

Our findings suggested that platinum- and irinotecan-containing regimens exhibited some potential efficacy in patients with advanced PACC.

Pancreatic panniculitis and elevated serum lipase in metastasized acinar cell carcinoma of the pancreas: A case report and review of literature

BACKGROUND

Pancreatic panniculitis is an extremely rare condition associated with different underlying pancreatic disorders and characterized by subcutaneous fat necrosis induced by elevated serum lipase levels. These lesions usually affect the lower extremities and may precede abdominal symptoms of pancreatic disease. Acinar cell carcinoma (ACC) of the pancreas is a rare pancreatic neoplasm, accounting for only 1%-2% of pancreatic tumors in adults.

CASE SUMMARY

We present the case of a 72-year-old man with ACC of the pancreatic head and synchronous liver metastases. Both the primary tumor and liver metastases were resected. Serum lipase was elevated before surgery and decreased to normal postoperatively. Rising serum lipase levels at follow-up led to the diagnosis of hepatic recurrence. This disease progression was then accompanied by pancreatic panniculitis, with subcutaneous fat necrosis and acute arthritis. To the best of our knowledge, only 4 cases have been reported in the literature and each showed a similar association of serum lipase levels with pancreatic panniculitis and progression of ACC.

CONCLUSION

Clinical symptoms and progression of ACC may correlate with serum lipase levels, suggesting potential usefulness as a follow-up biomarker.

Successful BRAF/MEK inhibition in a patient with BRAF V600E-mutated extrapancreatic acinar cell carcinoma

Pancreatic acinar cell carcinoma (PAC) is a rare disease with a poor prognosis. Treatment options for metastatic PAC are limited and often follow chemotherapeutic regimens for pancreatic ductal adenocarcinoma. Although recurrent genomic alterations, such as BRAF fusions and defects in genes involved in homologous recombination DNA repair, have been described in PAC, data on the clinical efficacy of molecularly guided, targeted treatment are scarce. Here we describe the case of a 27-yr-old patient with BRAF^V600E-mutated PAC who was successfully treated with a combination of BRAF and MEK inhibitors. The patient presented to our clinic with abdominal pain and weight loss. Imaging showed extensive retroperitoneal disease as well as mediastinal lymphadenopathy. Because of elevated α-fetoprotein (AFP) levels and inconclusive histologic findings, a germ cell tumor was suspected; however, PEI chemotherapy was unsuccessful. A repeat biopsy yielded the diagnosis of PAC and treatment with FOLFIRINOX was initiated. Comprehensive molecular profiling within the MASTER (Molecularly Aided Stratification for Tumor Eradication Research) precision oncology program revealed a somatic BRAF^V600E mutation and a germline PALB2 stop-gain mutation. Therapy was therefore switched to BRAF/MEK inhibition, resulting in almost complete remission and disease control for 12 mo and a remarkable improvement in the patient's general condition. These results indicate that BRAF alterations are a valid therapeutic target in PAC that should be routinely assessed in this patient population.

One size does not fit all for pancreatic cancers: A review on rare histologies and therapeutic approaches

Exocrine pancreatic neoplasms represent up to 95% of pancreatic cancers (PCs) and are widely recognized among the most lethal solid cancers, with a very poor 5-year survival rate of 5%-10%. The remaining < 5% of PCs are neuroendocrine tumors that are usually characterized by a better prognosis, with a median overall survival of 3.6 years. The most common type of PC is pancreatic ductal adenocarcinoma (PDAC), which accounts for roughly 85% of all exocrine PCs. However up to 10% of exocrine PCs have rare histotypes, which are still poorly understood. These subtypes can be distinguished from PDAC in terms of pathology, imaging, clinical presentation and prognosis. Additionally, due to their rarity, any knowledge regarding these specific histotypes is mostly based on case reports and a small series of retrospective analyses. Therefore, treatment strategies are generally deduced from those used for PDAC, even if these patients are often excluded or not clearly represented in clinical trials for PDAC. For these reasons, it is essential to collect as much information as possible on the management of PC, as assimilating it with PDAC may lead to the potential mistreatment of these patients. Here, we report the most significant literature regarding the epidemiology, typical presentation, possible treatment strategies, and prognosis of the most relevant histotypes among rare PCs.

Patients With Acinar Cell Carcinoma of the Pancreas After 2005: A Large Population Study

OBJECTIVES

Acinar cell carcinoma of the pancreas is a rare tumor with limited data. We aim to evaluate the characteristics, treatments, and outcomes of pancreatic acinar cell carcinoma after 2005.

METHODS

We retrospectively reviewed patients with pancreatic acinar cell carcinoma treated in Peking University Cancer Hospital and Institute (2005-2018) and identified cases from Surveillance, Epidemiology, and End Results database (2005-2015).

RESULTS

A total of 306 cases in our institute (n = 11) and Surveillance, Epidemiology, and End Results database (n = 295) were identified. The median age was 67 years, and 73.5% were male. The 5-year survival was 36.8% for all patients (median, 27 months). About 37% underwent surgical resection. The 5-year survival was 65.6% for resected patients as compared with 16.9% for unresected ones (P < 0.0001). Among locoregional and metastatic diseases, surgery significantly prolonged survival as well (P = 0.0003). Stage IV patients who received chemotherapy had a better survival than those without it (median, 16 vs 3 months; P = 0.0019). Aging, stage IV, and no surgery were independent predictors of poor overall survival.

CONCLUSIONS

For pancreatic acinar cell carcinoma, surgery is a potentially curative treatment contributing to long-term survival and suggested even in advanced diseases. Chemotherapy improved survival for metastatic patients.

Histopathological findings and canine pancreatic lipase immunoreactivity in normal dogs and dogs with inflammatory and neoplastic diseases of the pancreas

BACKGROUND

Diagnosis of pancreatic diseases in dogs is still challenging because of variable clinical signs, which do not always correspond with clinical pathology and histopathological findings.

OBJECTIVES

To characterize inflammatory and neoplastic pancreatic diseases of dogs and to correlate these findings with clinical findings and canine pancreatic lipase immunoreactivity (cPLI) results.

ANIMALS

Tissue specimens and corresponding blood samples from 72 dogs submitted for routine diagnostic testing.

METHODS

Four groups were defined histologically: (1) normal pancreas (n = 40), (2) mild pancreatitis (n = 8), (3) moderate or severe pancreatitis (acute, n = 11; chronic, n = 1), and (4) pancreatic neoplasms (n = 12). An in-house cPLI ELISA (<180 μg/L, normal; >310 μg/L, pancreatitis) was performed.

RESULTS

In dogs with normal pancreas, 92.5% of serum cPLI results were within the reference range and significantly lower than in dogs with mild acute pancreatitis, moderate or severe acute pancreatitis and pancreatic tumors. In dogs with moderate or severe acute pancreatitis, cPLI sensitivity was 90.9% (95% confidence interval [CI], 58.7%-99.8%). Most dogs (9/12) with pancreatic tumors (group 4) had additional pancreatic inflammation and cPLI results were increased in 10 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

High cPLI indicates serious acute pancreatitis but underlying pancreatic neoplasms should also be taken into consideration. This study confirms the relevance of histopathology in the diagnostic evaluation of pancreatic diseases.

Acinar cell carcinoma of the pancreas: a clinicopathologic and cytomorphologic review

Acinar cell carcinoma (ACC) is a rare malignancy of the pancreas with unique clinical, molecular, and morphologic characteristics. Clinically, these cancers can present with hypersecretory syndrome caused by the release of lipase into the circulation. Surgical resection is the treatment of choice for patients with organ-confined disease; however, with recent advances in precision medicine, therapies targeting the distinct molecular profile of ACC are on the horizon. Cytomorphologic features of ACC have been well described in the literature; and in conjunction with available clinical data and appropriate ancillary studies, an accurate diagnosis can be rendered in most instances. The aim of the current article is to present a comprehensive review of ACC based on available literature while attempting to shed light on some of its key histologic and cytologic characteristics.

Long-term survival of two patients with recurrent pancreatic acinar cell carcinoma treated with radiofrequency ablation: A case report

BACKGROUND

Pancreatic acinar cell carcinoma (PACC) is a rare type of malignant pancreatic cancer that represents approximately 1% of all pancreatic neoplasms. Due to its very low incidence, only a few retrospective studies are available. Although surgery is the first choice for treatment, most patients experience recurrence (mainly in the liver) and there are no clear recommendations for patients with advanced disease.

CASE SUMMARY

We report two patients with PACC treated with surgery who experienced tumour recurrence in the liver. Patient 1 carried a germline mutation in the APC gene. Both patients were treated with gemcitabine plus oxaliplatin and gemcitabine plus capecitabine as first- and second-line therapies, respectively. After a favourable response to chemotherapy, the patients underwent radiofrequency ablation of the remaining liver metastases. For patient 1, we documented a relapse in the liver after a disease-free period of 9 mo, and treatment with gemcitabine plus capecitabine was restarted. The patient achieved a complete response, and he remains alive without evidence of disease recurrence after six years. After radiofrequency ablation, patient 2 experienced disease-free survival for 21 mo, when peritoneal relapse was diagnosed and treated with chemotherapy. The patient achieved a stable disease state for nearly two years; nevertheless, further progressive disease was documented, and he died seven years after the first relapse.

CONCLUSION

PACC presents different biological behaviours than pancreatic adenocarcinoma. Multidisciplinary treatment involving local ablative therapies may be considered for PACC.

Histopathology and Feline Pancreatic Lipase Immunoreactivity in Inflammatory, Hyperplastic and Neoplastic Pancreatic Diseases in Cats

The most common pancreatic diseases in cats are pancreatitis and exocrine pancreatic insufficiency (EPI). Non-invasive methods, such as serological quantification of feline pancreatic lipase immunoreactivity (fPLI), are often used in the diagnosis of pancreatitis. Previous studies have compared fPLI concentrations with histopathology, considered to be the gold standard for diagnosis of feline pancreatitis. However, fPLI concentrations in cats suffering from pancreatic tumours were rarely described. The aim of the present study was to determine the sensitivity and specificity of an in-house enzyme-linked immunosorbent assay (ELISA) for the quantification of fPLI in serum samples based on histopathological findings in cats diagnosed with various pancreatic diseases. Pancreatic biopsy samples from 80 cats were included. Five groups were defined on the basis of pancreatic histopathology: group 1, normal pancreas; group 2, nodular hyperplasia; group 3, mild pancreatitis; group 4, marked (moderate/severe) pancreatitis; and group 5, pancreatic neoplasia. Serum samples from all cats were tested by fPLI ELISA (<3.6 μg/l normal, 3.6-5.3 μg/l questionable, >5.3 μg/l pancreatitis). In group 1 (n = 19), serum fPLI values were within the reference interval in 74% of cases and in group 2 (n = 9) in 78%. Cats with mild pancreatitis (n = 23), marked pancreatitis (n = 11) and pancreatic neoplasms (n = 18) had significantly increased fPLI concentrations compared with group 1 (P = 0.004/0.001/≤0.0001). Cats with nodular hyperplasia had significantly lower fPLI values than cats with marked pancreatitis (P = 0.048) or tumours (P = 0.002). Serum fPLI concentrations in group 3 were <3.6 μg/l (n = 6), 3.6-5.3 μg/l (n = 4) and >5.3 μg/l (n = 13). Calculated test sensitivity for mild pancreatitis was fPLI >3.5 μg/l: 73.9% and fPLI >5.3 μg/l: 56.5%. In group 4 (n = 11), seven of nine cats (77.8%) with marked purulent pancreatitis had elevated fPLI. In group 4, a sensitivity of 81.8% was detected for fPLI >3.5 μg/l and 63.6% for fPLI >5.3 μg/l. Two cats with marked non-purulent pancreatitis had elevated fPLI, while two cats with marked purulent pancreatitis had normal fPLI values (<3.6 μg/l). In group 5, one cat with pancreatic adenoma and one with pancreatic acinar carcinoma had normal fPLI concentrations. The other cats with pancreatic adenoma (solid, n = 1; cystic, n = 4) or carcinoma (solid, n = 9; cystic, n = 2) had elevated or high fPLI values (4.1 to >40 μg/l, median 21.2 μg/l), probably caused by additional inflammation. The results of the present study confirm the importance of detailed histopathological characterization for the interpretation of clinical signs and fPLI values in feline pancreatitis. Primary pancreatic neoplasms may also lead to elevated fPLI concentrations as there is concurrent pancreatitis in most cases. However, severe pancreatic diseases, such as chronic non-purulent pancreatitis or tumours without inflammation, may result in normal fPLI values.

Pancreatic acinar cell carcinoma--literature review and case report of a 56-year-old man presenting with abdominal pain

We present a case of acinar cell carcinoma of the pancreas (ACC) with metastasis to the liver in a patient who presented with complaints abdominal pain. The presentation, diagnosis, and management of a 56-year-old man with ACC are discussed here. Imaging with computerized tomography (CT) in particular is crucial in the diagnosis, which can identify the primary lesion as well as metastases. ACC should be considered in the differential as a source of abdominal, epigastric, or back pain with imaging that is suggestive of the diagnosis as prompt recognition and initiation of treatment is paramount in the overall prognosis.

Characterization of 22 Canine Pancreatic Carcinomas and Review of Literature

Pancreatic carcinomas are rare in dogs and clinical signs are mostly non-specific. The literature on clinically and pathologically characterized canine exocrine pancreatic tumours is limited to 76 cases reported since 1963. This retrospective study analysed formalin-fixed samples of pancreatic carcinomas from 22 dogs, obtained during elective exploratory surgery (n = 16) or if the dog was humanely destroyed (n = 6). Tumours were diagnosed according to the World Health Organization classification of tumours of the pancreas of domestic animals. In seven cases, blood samples taken during or shortly before surgery were analysed for concentrations of alpha-amylase, 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester lipase (DGGR lipase), C-reactive protein (CRP), alanine aminotransferase, glutamate dehydrogenase, alkaline phosphatase (ALP), canine trypsin-like immunoreactivity (cTLI) and canine pancreatic lipase immunoreactivity (cPLI). Neutrophil and lymphocyte numbers were determined as part of a complete blood count. Clinical signs were non-specific and included vomiting, inappetence and diarrhoea. Acinar carcinomas were most common (19/22) and observed growth patterns included: solid (n = 14), acinar (n = 5), clear cell (n = 3), mucinous (n = 2), trabecular (n = 1) or rosette-like (n = 1), occurring as a single pattern or in combination. Ductal carcinomas were identified in three cases. Pancreatitis was a common additional histological finding; five dogs had mild and nine dogs had severe pancreatitis. cPLI, DGGR lipase, cTLI and CRP were elevated in 5/5 acinar carcinomas. All liver enzymes were elevated in three of these five animals and ALP was increased in 4/5 dogs. Two dogs with ductal pancreatic carcinomas showed normal cPLI concentrations. One had increased CRP, liver enzymes and leucocytosis with neutrophilia, the other had elevated DGGR lipase and cTLI concentrations. Clinical findings in canine pancreatic carcinomas were non-specific and simultaneous inflammation can mask the detection of the underlying neoplasm in clinical examination and laboratory testing.

Characteristics and Outcomes of Pancreatic Cancer by Histological Subtypes

OBJECTIVES

Except pancreatic adenocarcinoma, pancreatic cancer has several uncommon histological subtypes, including invasive intraductal papillary mucinous neoplasm (IPMN), pancreatic neuroendocrine tumor (pNET), adenosquamous carcinoma, invasive mucinous cystic neoplasm (MCN), acinar cell carcinoma (ACC), squamous cell carcinoma (SCC), and invasive solid pseudopapillary tumor (SPT). However, features of theses uncommon subtypes are not systematically analyzed.

METHODS

Subjects with different histological subtypes of pancreatic cancers were retrieved from the Surveillance, Epidemiology, and End Results registry. Characteristics and behaviors of uncommon subtypes were compared.

RESULTS

Pancreatic adenocarcinoma (85.8%) represented most primary pancreatic cancers, and other subtypes were rare (14.2%). Features of uncommon subtypes included females with SPT and MCN, located at the pancreatic body/tail of pNET, SPT, and MCN; poor differentiation of adenosquamous carcinoma and SCC; and large size of MCN, SPT, ACC, and SCC. In addition, IPMN, pNET, MCN, ACC, and SPT were indolent. For indolent subtypes, patients with locoregional tumor had prominent prognosis compared with patients with distant disease, especially for invasive IPMN (median survival, localized, 30.0 months; regional, 11.0 months; distant, 4.0 months).

CONCLUSIONS

The study systematically summarizes characteristics and behaviors of primary pancreatic cancer by histological subtypes, which can facilitate the management of pancreatic cancer.

Pancreatic acinar cell carcinoma-case report and literature review

Background

Pancreatic acinar cell carcinoma (ACC) is a rare tumor that constitutes 1% of all pancreatic neoplasms. Pancreatic ACC has unique characteristics in terms of biological behavior, imaging and prognosis.

Case presentation

The present study reported two cases of pancreatic ACC confirmed by postoperative pathology and both cases exhibited several different imaging features and laboratory test results. Both cases had approximately 4 cm mass located in uncinate process of pancreas. Dilated intra- and extra-hepatic bile ducts was observed in one case, along with calcification. Heterogeneous enhancement of the tumor was exhibited in both patients with different intensities. Obstructive jaundice, elevated α-fetoprotein and CA 19–9 was found in one case, while the other case had normal liver function and tumor markers.

Conclusions

It was difficult to accurately diagnose pancreatic ACC before the operation despite its unique characteristics. Radical resection was the best treatment modality for resectable pancreatic ACC.

Systemic Chemotherapy for Advanced Rare Pancreatic Histotype Tumors: A Retrospective Multicenter Analysis

OBJECTIVES

Two issues were put forth by clinicians in the management of the advanced stages of rare variants of pancreatic ductal adenocarcinoma and other exocrine histotypes with peculiar clinical and pathological features: Do chemotherapy regimens recommended in pancreatic ductal adenocarcinoma patients have a clinical activity in rare pancreatic tumors? Or should other chemotherapy combinations be considered in this subset of patients?

METHODS

We conducted a multicenter retrospective study that collected data from 2005 to 2016 at 14 Italian cancer centers with the aim to evaluate tumor response and time to progression for first- and second-line and overall survival.

RESULTS

Of approximately 4300 exocrine pancreatic cancer patients, 79 advanced cases affected by rare histological types were identified, with pancreatic acinar cell cancer (n = 23), pancreatic adenosquamous cancer (n = 16), and mucinous cystic neoplasm with an associated invasive mucinous cystadenocarcinoma (n = 15) most represented. Survival analyses for each subgroup in relation with the different chemotherapy regimens showed the lack of statistical significance correlations.

CONCLUSIONS

Because of the lack of clinical trials in patients affected by these rare pancreatic histotypes, only their molecular classification would help clinicians in future therapeutic choice.