Pancreatic-type acinar cell carcinoma of the liver: a clinicopathologic study of four patients

Recent Advances in Pathology of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICCA) is a malignant epithelial neoplasm characterized by biliary differentiation within the liver. ICCA is molecularly heterogeneous and exhibits a broad spectrum of histopathological features. It is a highly aggressive carcinoma with high mortality and poor survival rates. ICCAs are classified into two main subtypes: the small-duct type and large-duct types. These two tumor types have different cell origins and clinicopathological features. ICCAs are characterized by numerous molecular alterations, including mutations in KRAS, TP53, IDH1/2, ARID1A, BAP1, BRAF, SAMD4, and EGFR, and FGFR2 fusion. Two main molecular subtypes-inflammation and proliferation-have been proposed. Recent advances in high-throughput assays using next-generation sequencing have improved our understanding of ICCA pathogenesis and molecular genetics. The diagnosis of ICCA poses a significant challenge for pathologists because of its varied morphologies and phenotypes. Accurate diagnosis of ICCA is essential for effective patient management and prognostic determination. This article provides an updated overview of ICCA pathology, focusing particularly on molecular features, histological subtypes, and diagnostic approaches.

Rapid Response to the Combination of Lenvatinib and Sintilimab in a Pancreatic Acinar Cell Carcinoma Patient With Elevated Alpha-Fetoprotein: A Case Report

A 48-year old woman was diagnosed with metastatic pancreatic acinar cell carcinoma (PACC) and with a marked elevation in alpha-fetoprotein (AFP), this being a recognized but uncommon feature of PACC. As she refused chemotherapy, the combined therapy of lenvatinib and sintilimab (lenvatinib 8 mg, orally, qd; and sintilimab 100 mg, intravenous glucose tolerance test, q21d) was given, which conferred significant tumor shrinkage and long progression-free survival (>21 months). This study is the first report and description of a PACC demonstrating favorable response to the combination therapy of an antiangiogenic agent and immunotherapy.

Primary extra-pancreatic pancreatic-type acinar cell carcinoma in the right perinephric space: A case report and review of literature

BACKGROUND

Primary extra-pancreatic pancreatic-type acinar cell carcinoma (ACC) is a rare malignancy, and has only been reported in the gastrointestinal tract, liver, and lymph nodes until now. Extra-pancreatic pancreatic-type ACC in the perinephric space has not been reported. Herein, we report the first case of ACC in the perinephric space and describe its clinical and imaging features, which should be considered when differentiating perinephric space neoplasms.

CASE SUMMARY

A 48-year-old man with a 5-year history of hypertension was incidentally found to have an asymptomatic right retroperitoneal mass during a routine health check-up. Laboratory tests were normal. Abdominal computed tomography and magnetic resonance imaging showed an oval hypervascular mass with a central scar and enhanced capsule in the right perinephric space. After surgical resection of the neoplasm, the diagnosis was primary extra-pancreatic pancreatic-type ACC. The patient was alive without recurrence or metastasis during a 15-mo follow-up.

CONCLUSION

This is the first report of an extra-pancreatic ACC in right perinephric space, which should be considered as a possible diagnosis in perinephric tumors.

Title: pancreatic-type mixed acinar neuroendocrine carcinoma of the stomach: a case report and review of the literature

BACKGROUND

The majority of gastrointestinal tumors are adenocarcinomas. Rarely, there are other types of tumors, such as acinar cell carcinoma, and these are often called pancreatic-type acinar cell carcinomas. Among these tumors, some are differentiated into neuroendocrine components. A few of them are MiNENs.

CASE PRESENTATION

The patient was an 80-year-old male who was referred to our hospital for treatment of a pedunculated gastric tumor. It was 5 cm in diameter and detected in the upper gastric body with upper GI endoscopy conducted to investigate anemia. In the biopsy, although hyperplasia of gastric gland cells was noted, no tumor cells were found. Retrospectively, the diagnosis was misdiagnosed. An operation was arranged because bleeding from the tumor was suspected as a cause of anemia and because surgical resection was considered to be desirable for accurate diagnosis. Hence, laparoscopic and endoscopic cooperative surgery was performed. In the pathological examination, several types of epithelial cells that proliferated in the area between the mucosa and deep inside the submucosa were observed. These consisted of acinar-glandular/trabecular patterns and solid. A diagnosis of pancreatic-type acinar cell carcinoma of the stomach with NET G2 and G3 was made based on characteristic cellular findings and the results of immunostaining tests. Each of them consisted of more than 30% of the lesion; a diagnosis of pancreatic-type mixed acinar neuroendocrine carcinoma (pancreatic-type MiNEN) of the stomach or a type of gastric MiNEN was obtained. Anemia was resolved after the operation, and the patient was discharged from the hospital without perioperative complications.

CONCLUSIONS

Pancreatic-type ACC of the stomach that is differentiated into neuroendocrine tumors is very rare. Hence, we report this case along with a literature review.

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.

Cytopathology and ultrastructure identification of primary hepatic acinar cell carcinoma: Case report

•

Acinar cell carcinoma originating in the liver proper remains a diagnostic quandary.

•

Non-specific imaging features may have led to prior misdiagnosis and poor outcomes.

•

Ultrastructural electron microscopy represents a novel tool for identification.

•

Heterotopia or metaplastic mechanisms may underlie hepatic acinar cell localization.

•

The previous literature is summarized in context of the present case of hepatic ACC.

Introduction

A primary acinar cell carcinoma (ACC) of the liver was incidentally diagnosed in a clinically asymptomatic 80-year-old man. This study aimed to delineate critical diagnostic characteristics of an ACC originating uniquely from the liver to improve its future identification.

Presentation of case

Enhanced MRI revealed a heterogenous, cystic 7.7 × 11.1 × 10.4 cm tumour occupying hepatic segments II and III. The mass demonstrated mild diffuse enhancement in hepatic arterial phase with minimal portal venous washout in a liver without cirrhotic features. A central stellate T2-hyperintense necrotic scar and outer capsule were apparent. No primary lesion or metastasis outside the liver was discernable. Post-left hepatic lobectomy, the tumour immunophenotype was atypical for presumptive diagnoses of hepatocellular carcinoma (HCC) or cholangiocarcinoma. Extensive morphologic workup on electron microscopy definitively diagnosed primary hepatic ACC by establishing presence of secretory zymogen-like granules, intracytoplasmic microvilli and acinar cell differentiation. Cytopathology revealed cellular lumen expressing PAS-positive diastase-resistant granular cytoplasmic contents.

Discussion

This case showcased the novel utility of electron microscopy that was crucial in yielding the definitive diagnosis. The previous literature on hepatic ACC was compiled here in context of the present case. The mechanism of hepatic acinar cell localization was also discussed.

Conclusion

Primary hepatic ACC may easily be confused for other lesions due to nonspecific imaging patterns. Specifically, the presence of a central scar without risk factors for HCC can favour a diagnosis of benign entities such as focal nodular hyperplasia (FNH). Electron microscopy presents an important tool to identify primary hepatic ACC and may improve future patient outcomes.

Lipase hypersecretion syndrome: A distinct form of paraneoplastic syndrome specific to pancreatic acinar carcinomas

Lipase hypersecretion syndrome (LHS) is a paraneoplastic syndrome seen exclusively as a result of pancreatic acinar cell carcinoma (ACC). In LHS, acinar enzymes (lipase, trypsin and chymotrypsin) which are normally secreted to the duodenum for digestive purposes, are instead released to the blood by the carcinoma cells. In a way, it is "endocrine-ization" of an "exocrine" function. These circulating enzymes, especially lipase, exerts its digestive action on other tissues, especially on the subcutaneous tissues in the pressure poins of legs, creating a picture often mistaken as erythema nodosum or rheumatic nodules. The bone and joints may also be effected, which mostly appears to be secondary to the complications and super-infection of the skin lesions. Eosinophilia also often accompanies this syndrome. The accurate diagnosis of LHS requires the identification of the pancreatic primary as well as its correct classification as acinar because a variety of pancreatic tumors can be associated with skin lesions, ranging from rare metastasis of adenocarcinoma to the necrolytic migratory erythema caused by glucagon-producing neuroendocrine tumors. Towards this differential, the diagnostic characteristics of acinar cell carcinomas that have been better elucidated in the past decade often need to be employed in increasingly smaller specimens and the liver, especially since most LHS cases also have liver metastasis (presumably due to the by-pass of the "first-pass" liver metabolism phenomenon). ACC (and LHS) occur in patients in their 60's. The pancreatic mass is often large, round, demarcated and closely resemble neuroendocrine and solid-pseudopapillary neoplasms but are more atypical/proliferative, and commonly show single prominent nucleoli and a distinctive chromophilia. Immunostaining with trypsin/chymotrypsin, negativity of beta-catenin help in the differential; as a caveat, neuroendocrine differentiation is common in ACCs. In conclusion, LHS is a rare type of paraneoplastic syndrome specific to ACC. The accurate diagnosis requires attention to their subtle diagnostic characteristics.

Hepatobiliary and Pancreatic: Primary acinar cell carcinoma of the liver showing good response to chemotherapy

A 48-year old man with no history of liver disease or alcohol addiction developed jaundice, itching and dark urine without any symptom of abdominal pain.

A CT examination revealed the presence of a liver mass extending between segments 4, 5 and 8 that was found to be an acinar cell carcinoma at biopsy. The primary hepatic origin was confirmed mainly excluding a primary pancreatic tumor by diagnostic work-up.

Since the lesion was considered unresectable at the time of the diagnosis, the patient underwent to Xeloda and oxaliplatin neoadjuvant chemotherapy, with progressive reduction in size of the mass as a sign of good response to therapy.

A FISH assay efficiently screens for BRAF gene rearrangements in pancreatic acinar-type neoplasms

Approximately 1-2% of pancreatic neoplasms are acinar cell carcinomas. Recently, BRAF gene rearrangements were identified in over 20% of acinar-type neoplasms, which included both pure acinar cell carcinomas and mixed carcinomas with acinar differentiation, using next-generation sequencing-based platforms, providing a potential therapeutic target for patients with these neoplasms. Thus, it is clinically important to develop a rapid, cost- and material-efficient assay to screen for BRAF gene fusions in pancreatic acinar-type neoplasms. We developed a dual color, break-apart FISH assay to detect BRAF gene rearrangements in these neoplasms and evaluated its performance in comparison to next-generation sequencing-based studies. A blinded BRAF rearrangement FISH investigation was performed on 31 acinar-type neoplasms that had been studied previously by next-generation sequencing-based analysis as well as on 18 additional acinar-type neoplasms that were accrued over the past 2 years. In total, BRAF fusions were identified in 12/49 (24%) acinar-type neoplasms by FISH. BRAF fusion partners were uncovered by using targeted next-generation sequencing studies in 11 FISH-positive cases that had sufficient material for next-generation sequencing studies. SND1 was the most frequent fusion partner involved in BRAF-fusion acinar-type neoplasms (50%), followed by HERPUD1 (18%). No BRAF fusions were identified by next-generation sequencing in any of the FISH-negative cases investigated. FISH analysis showed that BRAF rearrangements were diffusely present across tumor-rich areas in BRAF-fusion acinar-type neoplasms, which is consistent with an oncogenic driver alteration pattern. Thus, we demonstrated that, in comparison to targeted next-generation sequencing-based technologies, the FISH assay is highly sensitive and specific as well as time- and cost-efficient in the detection of BRAF fusions in acinar-type neoplasms. The FISH assay can be easily implemented in diagnostic settings to identify acinar-type neoplasms patients potentially suitable for targeted therapy to inhibit MAPK pathway activity.

Case report: primary acinar cell carcinoma of the liver treated with multimodality therapy

We describe a case of primary acinar cell carcinoma (ACC) originating in the liver in a 54-year-old female, diagnosed following persistent abnormal elevated liver function. Imaging revealed two masses, one dominant lesion in the right hepatic lobe and another in segment IVA. A right hepatectomy was performed to remove the larger lesion, while the mass in segment IVA was unresectable due to its proximity to the left hepatic vein. Immunohistochemical staining showed positivity for trypsin and chymotrypsin. Postoperatively the patient underwent hepatic arterial embolization of the other unresectable lesion followed by FOLFOX chemotherapy. At 20 months from diagnosis the patient is currently under observation with a decreasing necrotic mass and no other disease evident. Based on histology, immunohistochemistry and radiological findings a diagnosis of primary ACC of the liver was made. Genomic assessment of somatic mutations within the patient's tumor was also performed through next generation sequencing and findings were consistent with an acinar malignancy. This case highlights a rare tumor subtype treated with a combination of therapeutic modalities through a multidisciplinary approach.

Metastatic pancreatic acinar cell carcinoma in a younger male with marked AFP production: A potential pitfall on fine needle aspiration biopsy

A 30-year-old male presented to his doctor with complaints of abdominal pain and was found to have retroperitoneal as well as multiple hepatic masses. A serum alpha-fetoprotein (AFP) level was significantly elevated (17,373 ng mL^-1 ), raising suspicions for a metastatic germ cell tumor. Fine needle aspiration biopsy of the pancreatic lesion revealed atypical epithelioid cells with round nuclei, large prominent nucleoli, and granular cytoplasm. The morphologic differential diagnosis included pancreatic neoplasm, metastatic germ cell tumor, other metastatic carcinoma, and melanoma. An extensive panel of immunohistochemical stains confirmed the diagnosis of acinar cell carcinoma. The diagnosis of acinar cell carcinoma could be confounded by the markedly increased AFP level, particularly in the setting of a retroperitoneal mass in a younger male. The increased AFP level in the setting of an acinar cell tumor is a potential pitfall to correct diagnosis by cytology. As the treatment for these two entities differs considerably, acute awareness of the phenomenon is important. We present a case of pancreatic ACC with an increased AFP level diagnosed on a cytology specimen. Diagn. Cytopathol. 2017;45:133-136. © 2016 Wiley Periodicals, Inc.

Pancreatic panniculitis in a patient with pancreatic-type acinar cell carcinoma of the liver--case report and review of literature

Background

Pancreatic panniculitis is a rare condition, which has only been described in relation with pancreatic diseases up to now. It is characterized by necrotizing subcutaneous inflammation and is thought to be triggered by adipocyte necrosis due to systemic release of pancreatic enzymes with consecutive infiltration of neutrophils. We present the first case of a patient with pancreatic panniculitis caused by pancreatic-type primary acinar cell carcinoma (ACC) of the liver and without underlying pancreatic disease.

Case presentation

A 73-year old Caucasian female patient was referred to our department with painful cutaneous nodules persisting for eight weeks and with marked lipasemia (~15000 U/l; normal range <60 U/l). Four weeks prior, several liver lesions had been detected. Empiric treatment with steroids did not show any effect. A biopsy of the skin nodules revealed “pancreatic” panniculitis, while abdominal imaging with ultrasound, computed tomography and magnetic resonance imaging detected no abnormal pancreatic findings. Ultrasound-guided biopsy of the liver lesions showed infiltrates of an ACC. The patient died soon thereafter. Autopsy failed to reveal any other primary for the ACC, so that a pancreatic-type ACC of the liver was diagnosed by exclusion.

One hundred thirty cases of pancreatic panniculitis published within the last 20 years are reviewed. ACC of the pancreas is the most common underlying neoplastic condition. Patients with associated neoplasm are significantly older, take longer to be diagnosed and have higher lipase levels than patients with underlying pancreatitis.

Extrapancreatic pancreatic-type ACC is very rare, but shows the same biological features as ACC of the pancreas. It is believed to develop from metaplastic or ectopic pancreatic tissue. Up to now, no pancreatic panniculitis in extrapancreatic ACC has been described.

Conclusion

Pancreatic panniculitis should always be included in the differential diagnosis of lipolytic panniculitic lesions. It can be regarded as a facultative paraneoplastic phenomenon.

When suspected, a thorough work-up for identification of the underlying disease is mandatory and extrapancreatic lesions (e.g. liver) should also be considered. While administration of octreotide or steroids can sometimes alleviate symptoms, immediate treatment of the associated condition is the only effective management option.

Acinar Cell Carcinoma of the Pancreas: Overview of Clinicopathologic Features and Insights into the Molecular Pathology

Acinar cell carcinomas (ACCs) of the pancreas are rare pancreatic neoplasms accounting for about 1–2% of pancreatic tumors in adults and about 15% in pediatric subjects. They show different clinical symptoms at presentation, different morphological features, different outcomes, and different molecular alterations. This heterogeneous clinicopathological spectrum may give rise to difficulties in the clinical and pathological diagnosis with consequential therapeutic and prognostic implications. The molecular mechanisms involved in the onset and progression of ACCs are still not completely understood, although in recent years, several attempts have been made to clarify the molecular mechanisms involved in ACC biology. In this paper, we will review the main clinicopathological and molecular features of pancreatic ACCs of both adult and pediatric subjects to give the reader a comprehensive overview of this rare tumor type.

DNA mismatch repair abnormalities in acinar cell carcinoma of the pancreas: frequency and clinical significance

OBJECTIVES

Acinar cell carcinoma (ACC), including its mixed variants, is a rare pancreatic malignancy. Recent reports have documented its occurrence in Lynch syndrome. Our aim was to evaluate the frequency and clinicopathologic significance of DNA mismatch repair (MMR) deficiency in ACCs in general.

METHODS

Mismatch repair protein expression was evaluated by immunohistochemistry in a series of 36 ACC cases that were treated at our institution and had sufficient clinical information and pathologic material.

RESULTS

Loss of MMR protein was observed in 5 ACCs (5/36, 14%): 2 lost MLH1/PMS2, 2 lost MSH2/MSH6, and 1 lost MSH6 alone. The 1 MSH6-deficient case and 1 of the 2 MSH2/MSH6-deficient cases had a known history of Lynch syndrome, carrying a germline mutation in MSH6 and MSH2, respectively. None of the 5 tumors showed distinctive morphology. Two of the 5 patients died of disease 6 and 21 months after diagnosis. In contrast, in the MMR-normal group, only 1 of 30 patients died of disease (median follow-up, 32.5 months).

CONCLUSIONS

Mismatch repair protein deficiency is not uncommon in ACCs, occurring in 14% of the cases in this series. The MMR-deficient ACCs did not show distinctive morphologic features and were clinically no less aggressive than MMR-normal ACCs.

Acinic cell carcinoma of the breast: review of the literature

INTRODUCTION

The breast and salivary gland tissue share embryologic and thus pathological similarities. Acinic cell carcinoma (ACC) is a typical tumor in salivary glands, but rarely arises in breast too. We reviewed 38 cases of mammary ACC reported in literature and our case, the first ACC born within a fibroadenoma.

MATERIALS AND METHODS

Data were collected by a research for the key words acinic cell carcinoma breast on Pubmed in March 2014, including a case treated in our department. All reviewed cases were compared for clinical approach and histological pattern.

RESULTS

To date 23 articles presenting cases of ACC of the breast are reported in literature. We included in our review 38 cases previously described and one new case. The histological pattern was predominantly solid with a microglandular structure. All the tumor cells were cytologically characterized by monotonous round cells with a finely granular, weakly eosinophilic, or clearly vacuolated cytoplasm. The most of the cells were intensely stained with anti-lysozime, anti-amylase, anti-α1-chimotripsin, anti-EMA and anti-S100 protein antisera. Immunohistochemistry was also performed to point out: estrogen receptor (ER), progesterone receptor (PR), androgen receptors (AR), human epidermal growth factor receptor 2 overexpression (HER2/neu), E-cadherin (E-cad), cytokeratin-7 (CK7), gross cystic disease fluid protein 15 (GCDFP15), smooth muscle actin (SMA).

CONCLUSION

ACC of the breast is a rare tumor, showing similarities with the salivary gland counterpart, above all in terms of good prognosis, and differences from the ordinary invasive breast carcinoma. Further investigations are needed to elucidate the true histogenesis and the correct treatment.

Acinar cell carcinoma of the pancreas: clinical and cytomorphologic characteristics

Acinar cell carcinoma is a rare malignant epithelial neoplasm with predominantly exocrine acinar differentiation and is seen primarily in older men (mean age, 62 years). The presenting symptoms are usually non-specific, and jaundice is often not present. Symptoms relating to the overproduction and release of lipase into the circulation are present in 10-15% of patients. Characteristic cytomorphologic features include a population of cells with minimal pleomorphism, eccentrically placed nuclei with a single prominent nucleoli and moderate hyperchromasia. The cytoplasm is finely granular, and the background may contain granular debris secondary to cytolysis. A significant proportion of the cases also have a minor neuroendocrine component or scattered neuroendocrine cells. Approximately 50% of patients have metastatic disease at presentation, often restricted to the regional lymph nodes and liver. The prognosis is poor, only slightly better than that of pancreatic ductal adenocarcinoma.

First description of an acinic cell carcinoma of the breast in a BRCA1 mutation carrier: a case report

Background

Acinic cell carcinoma (ACC) is a rare malignant epithelial neoplasm characterized by the presence of malignant tubular acinar exocrine gland structures. Diagnosis is generally made in salivary glands and in the pancreas. ACC of the breast has been reported in few cases only. Carriers of inherited mutations in the BRCA1 gene are prone to the development of breast cancer, mainly invasive ductal or medullary type carcinomas. We describe for the first time a BRCA1 mutation carrier with a diagnosis of ACC of the breast.

Case presentation

The patient developed an invasive ductal carcinoma (IDC) at the age of 40 years and an ACC in the contralateral breast at 44 years. Immunohistochemical examination of the ACC revealed a triple negative status (i.e., negativity for estrogen receptor, progesterone receptor and HER2 protein) and positivity for p53. Using a combination of loss of heterozygosity (LOH) and sequencing analyses, the loss of the wild-type BRCA1 allele was detected in both the ACC and the IDC. In addition, two different somatic TP53 mutations, one in the ACC only and another one in the IDC only, were observed.

Conclusion

Both the immunohistochemical and molecular features observed in the ACC are typical of BRCA1-associated breast cancers and suggest an involvement of the patient’s germline mutation in the disease. The occurrence of rare histological types of breast cancers, including malignant phyllodes tumor, atypical medullary carcinoma and metaplastic carcinoma, in BRCA1 mutation carriers has been already reported. Our findings further broaden the spectrum of BRCA1-associated breast malignancies.