Intraductal acinar cell carcinoma of the pancreas

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

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.

Pancreatic acinar cell carcinoma with predominant extension into the main pancreatic duct: A case report

A 34‐year‐old male was referred to our hospital for a possible pancreatic mass detected by computed tomography (CT) that was performed to find the cause of acute pancreatitis. Multiple imaging tests, including contrast‐enhanced CT scan, magnetic resonance imaging, contrast‐enhanced endoscopic ultrasonography, and endoscopic retrograde pancreatography, revealed a solid mass occupying the head of the main pancreatic duct (MDP), and pancreaticoduodenectomy was performed. In the resected specimen, the tumor showed expansive growth from the pancreatic parenchyma to the MDP and formed a tumor plug. Histopathological findings together with immunostaining findings led to the diagnosis of pancreatic acinar cell carcinoma (PACC). The patient was alive and recurrence‐free for 11 years after surgery. Extension into the MDP is more common in PACC than in conventional pancreatic ductal adenocarcinoma. PACC patients with MDP extension may have less aggressive clinicopathologic characteristics, and a relatively good prognosis can be expected.

Pancreatic Neoplasms With Acinar Differentiation: A Review of Pathologic and Molecular Features

CONTEXT.—

Pancreatic acinar lesions encompass a broad spectrum of malignant tumors and benign reactive processes affecting both adults and children, with clinical, pathologic, and molecular features that are distinct from more common ductal neoplasms. Accurate morphologic diagnosis and molecular assessment of these uncommon neoplasms is critical for effective patient care.

OBJECTIVE.—

To review the clinical, pathologic, and molecular features of pancreatic neoplasms with acinar differentiation, the most common of which is acinar cell carcinoma but which also includes mixed carcinomas with acinar components, cystic acinar lesions, and pancreatoblastoma.

DATA SOURCES.—

We assessed the current primary literature, as well as recently updated diagnostic manuals.

CONCLUSIONS.—

Pancreatic acinar neoplasms are a morphologically and molecularly heterogeneous group of diseases that are characterized by acinar differentiation of at least a subset of the neoplastic cells, defined either morphologically (granular cytoplasm, single prominent nucleoli) or immunohistochemically. Squamoid nests are a key morphologic feature of pancreatoblastoma. Alterations in WNT signaling and chromosomal 11p loss are common molecular features of both acinar cell carcinoma and pancreatoblastoma. Targetable molecular alterations in acinar carcinoma include BRAF rearrangements and DNA repair defects, including mismatch repair deficiency and BRCA pathway defects. For practicing pathologists, morphologic recognition of such acinar neoplasms is critical, and in the future, molecular diagnostics to identify lesions susceptible to targeted therapy will likely form an important component of patient care.

Pancreatic acinar cell carcinoma with extension into the main pancreatic duct: a case report

Background

Pancreatic acinar cell carcinoma (PACC) is a rare exocrine malignant tumor. Its widespread intraductal extension into the main pancreatic duct (MPD) is also rare.

Case presentation

We report the case of a 71-year-old man with PACC with MPD extension. The patient was assessed with laboratory and radiographic investigations that facilitated a preoperative diagnosis. Endoscopic ultrasonography (EUS) and dynamic thin-slice multi-detector row computed tomography (MDCT) were useful for determining the resection line of the pancreas. EUS-guided fine needle aspiration (EUS-FNA) was also helpful in determining the tumor biology and treatment strategy. Distal pancreatectomy was performed. The MPD was occupied by the tumor 35 mm downstream and 5 mm upstream. Histopathologically, the pancreatic tail tumor extended continuously into the MPD. The tumor was solid with cells showing eosinophilic and granular cytoplasm, indicating the diagnosis of PACC. This is an interesting case of PACC with intraductal extension into the MPD. We discuss the possible mechanisms of tumor extension in this rare case together with a review of the literature.

Conclusions

We describe a rare pancreatic acinar cell carcinoma that could be adequately treated using preoperative precise imaging and histopathological evaluations. When an intraductal tumor extension in the MPD is encountered, the diagnosis of a rare pancreatic tumor should be considered, as in our case.

Pancreatic Neuroendocrine Neoplasm Invading the Entire Main Pancreatic Duct Diagnosed by a Preoperative Endoscopic Biopsy

A 78-year-old man was referred to our hospital for a detailed examination of a pancreatic tumor that filled the main pancreatic duct (MPD). The histological diagnosis of the endoscopic biopsy specimen was neuroendocrine tumor (NET) G3. The patient subsequently underwent total pancreatectomy. The histological diagnosis of the surgical specimen was also NET G3. This is the first report of a NET that occupied the MPD and was diagnosed by a preoperative endoscopic biopsy through the papilla of Vater. This case is a good example of a histopathological diagnostic method for pancreatic tumors invading the entire MPD.

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.

Cancerization of the Pancreatic Ducts: Demonstration of a Common and Under-recognized Process Using Immunolabeling of Paired Duct Lesions and Invasive Pancreatic Ductal Adenocarcinoma for p53 and Smad4 Expression

Invasive pancreatic ductal adenocarcinoma (PDAC) can infiltrate back into and spread along preexisting pancreatic ducts and ductules in a process known as cancerization of ducts (COD). Histologically COD can mimic high-grade pancreatic intraepithelial neoplasia (HG-PanIN). We reviewed pancreatic resections from 100 patients with PDAC for the presence or absence of ducts with histologic features of COD. Features supporting COD included adjacent histologically similar invasive PDAC and an abrupt transition between markedly atypical intraductal epithelium and normal duct epithelium or circumferential involvement of a duct. As the TP53 and SMAD4 genes are frequently targeted in invasive PDAC but not HG-PanIN, paired PDAC and histologically suspected COD lesions were immunolabeled with antibodies to the p53 and Smad4 proteins. Suspected COD was identified on hematoxylin and eosin sections in 89 (89%) of the cases. Immunolabeling for p53 and Smad4 was performed in 68 (76%) of 89 cases. p53 was interpretable in 55 cases and all 55 (100%) cases showed concordant labeling between COD and invasive PDAC. There was matched aberrant p53 immunolabeling in 37 (67%) cases including overexpression in 30 (55%) cases and lack of expression in 7 (13%) cases. Smad4 immunolabeling was interpretable in 61 cases and 59 (97%) cases showed concordant labeling between COD and invasive PDAC. Matched loss of Smad4 was seen in 28 (46%) cases. The immunolabeling of invasive PDAC and COD for p53 and Smad4 supports the high prevalence of COD observed on hematoxylin and eosin and highlights the utility of p53 and Smad4 immunolabeling in differentiating COD and HG-PanIN.

Pancreatic acinar cell carcinoma with extensive tumor embolism at the trunk of portal vein and pancreatic intraductal infiltration

A 59-year-old man was admitted to the hospital with acute pancreatitis. The cause was suggested to be a pancreatic tumor based on computed tomography (CT). The pancreatic tumor was 45 mm with an extensive tumor embolism at the trunk of the portal vein and intraductal infiltration of the main pancreatic duct (MPD). The pancreatic tumor was diagnosed as acinar cell carcinoma (ACC) by endoscopic ultrasound guided fine needle aspiration. Therefore, the cause of acute pancreatitis was diagnosed to be intraductal infiltration of ACC in the MPD. Chemotherapy was initially performed because it was difficult to perform surgery due to extensive tumor embolism at the trunk of the portal vein. Degeneration and reduction of ACC and tumor embolism of the portal vein was noted on CT after chemotherapy, and extended distal pancreatectomy with portal vein reconstruction was performed. There has been no relapse for 5 years postoperative follow-up. This is an interesting and rare case because ACC with intraductal infiltration of MPD is low in frequency; most ACCs are asymptomatic when they are found, and many cases tend to have poor prognosis in spite of surgical cases.

Acinar cell carcinoma of the pancreas presenting as diffuse pancreatic enlargement: Two case reports and literature review

RATIONALE

Pancreatic acinar cell carcinoma (ACC) is a rare malignant tumor of exocrine pancreas. It is typically a well-marginated large solid mass arising in a certain aspect of the pancreas. Diffuse involvement of ACC in the pancreas is very rare, and may simulate pancreatitis in radiological findings. We report 2 cases of ACC presenting as diffuse enlargement of the pancreas due to tumor involvement without formation of a distinct mass.

PATIENT CONCERNS

The patients consisted of a 41-year-old man with weight loss and a 77-year-old man who was asymptomatic.

DIAGNOSES

Computed tomography (CT) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT showed diffuse enlargement of the pancreas forming a sausage-like shape with homogenously increased FDG activity.

INTERVENTIONS

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) biopsy of the pancreatic lesion was performed.

OUTCOMES

Histopathology results from the pancreas confirmed the diagnosis of pancreatic ACC.

LESSONS

Because diffuse enlargement of the pancreas is a common imaging feature of pancreatitis, recognition of this rare morphologic pattern of ACC is important for radiological diagnosis of this tumor.

Intraductal Tubulopapillary Neoplasm of the Pancreas: A Clinicopathologic and Immunohistochemical Analysis of 33 Cases

Intraductal tubulopapillary neoplasm (ITPN) is a relatively recently described member of the pancreatic intraductal neoplasm family. Thus, the literature on its histologic and immunohistochemical features, clinical behavior, and its similarities and differences from other pancreatic neoplasms is limited. Thirty-three cases of ITPN, the largest series to date, were identified. Immunohistochemical labeling for cytokeratins, glycoproteins, pancreatic enzymes, markers for intestinal and neuroendocrine differentiation, and antibodies associated with genetic alterations previously described in pancreatic neoplasms was performed. Clinicopathologic features and survival was assessed. Seventeen patients were female and 14 were male. Mean age was 55 years (range, 25 to 79 y). Median overall tumor size was 4.5 cm (range, 0.5 to 15 cm). Forty-five percent of the tumors occurred in the head, 32% in the body/tail, and 23% showed diffuse involvement. Microscopically, the tumors were characterized by intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. Although it was often challenging to determine its extent, invasion was present in 71%. Almost all tumors labeled for CAM5.2, CK7, and CK19; most expressed CA19.9, MUC1, and MUC6. CDX2, MUC2, trypsin, chymotrypsin, chromogranin, and synaptophysin were not expressed. SMAD4 expression was retained in 100%; p16 expression and p53 overexpression was seen in 33% and 27%, respectively. Follow-up information was available for 22 patients (median follow-up, 45 mo; range, 11 to 173 mo). Two patients with invasive carcinoma died of disease at 23 and 41 months, respectively. One patient died of unrelated causes at 49 months. Twelve patients were alive with disease. Seven patients were alive with no evidence of disease. The overall 1-, 3-, and 5-year survival rates were 100% in patients without an invasive component and 100%, 91%, and 71%, respectively, in patients with an invasive component (P=0.7). ITPN is a distinct clinicopathologic entity in the pancreas. Despite the difficulties of determining the extent of invasive carcinoma in many cases, the overall outcome seems to be relatively favorable and substantially better than that of conventional pancreatic ductal adenocarcinoma, even when only the cases with invasive carcinoma are considered.

Nonductal Pancreatic Cancers

Nonductal pancreatic neoplasms, including solid pseudopapillary neoplasms, acinar cell carcinomas, and pancreatoblastomas, are uncommon. These entities share overlapping gross, microscopic, and immunohistochemical features, such as well-demarcated solid neoplasms, monotonous cellular tumor cells with little intervening stroma, and abnormal beta-catenin expression. Each tumor also has unique clinicopathologic characteristics with diverse clinical behavior. To differentiate nonductal pancreatic neoplasms, identification of histologic findings, such as pseudopapillae, acinar cell features, and squamoid corpuscles, is important. Immunostainings for acinar cell or neuroendocrine markers are helpful for differential diagnosis. This article describes the clinicopathologic and immunohistochemical features of nonductal pancreatic cancers.

Difficult Diagnostic Problems in Pancreatobiliary Neoplasia

CONTEXT

Many common diagnostic dilemmas are encountered in pancreatobiliary pathology, frequently resulting in uncertainty on behalf of the pathologist and referral for a second opinion.

OBJECTIVES

To review 4 common diagnostic dilemmas encountered in the practice of pancreatobiliary pathology: (1) pancreatic ductal adenocarcinoma versus chronic pancreatitis; (2) pancreatic ductal carcinoma versus adenocarcinomas arising in the ampulla and intrapancreatic common bile duct; (3) the distinction of uncommon intraductal neoplasms--intraductal oncocytic papillary neoplasm, intraductal tubulopapillary neoplasm, and intraductal acinar cell carcinoma; and (4) intrahepatic cholangiocarcinoma versus metastatic carcinoma.

DATA SOURCES

A review of pertinent literature, along with the authors' personal experience, based on institutional and consultation materials.

CONCLUSIONS

Important diagnostic features for a few challenging problems in pancreatobiliary pathology are reviewed. Careful study of the microscopic features along with awareness of differential diagnoses and diagnostic pitfalls generally allows distinction of these entities. We also highlight established and novel ancillary studies that help to arrive at an accurate diagnosis.

Long-term survival following pancreatectomy and s-1 chemotherapy for pancreatic acinar cell carcinoma with peritoneal dissemination: a case report and literature review

Current case is the third report of S-1 chemotherapy against acinar cell carcinoma (ACC) of pancreas, and our patient has achieved the longest reported recurrence-free survival, longer than 6 years, despite the presence of disseminated nodules at laparotomy.A 77-year-old man presented with abdominal discomfort. Computed tomography showed a low-density tumor in the pancreas tail and the patient was referred for surgery. A 3-cm sized pancreatic tumor, with localized disseminated nodules, was detected on laparotomy. Distal pancreatectomy with concomitant resection of disseminated nodules was performed, and histopathological examination revealed an ACC. Oral S-1 chemotherapy was administered postsurgery, and the patient showed no sign of recurrence during 73 months of follow-up. This is the first report of long-term survivor of pancreatic ACC with peritoneal dissemination, following pancreatectomy and S-1 chemotherapy.Current case suggests a beneficial effect of S-1 chemotherapy in cases of ACC.

Brush cytology of acinar cell carcinoma of the pancreas with intraductal growth: a case report

We describe a rare case of pancreatic acinar cell carcinoma (ACC) with intraductal growth in a 77-year-old man, which was diagnosed by endoscopic brush cytology. Preoperative imaging revealed an ill-defined mass involving the main pancreatic duct of the body, which was suspected to be an invasive ductal carcinoma. Endoscopic brush cytology showed several thick, small to large clusters of tumor cells. However, a loosely cohesive or individual cell arrangement was more prominent. Singly dispersed naked nuclei, occasionally with crush artifact, were frequently observed. The nuclear contour was smooth and chromatin was finely clumped. The cytoplasm contained many coarse D-PAS-positive granules. Histologically, the tumor expansively invaded to parenchyma and expanded to fill the pancreatic ducts. Ultrastructurally, the tumor cells were less cohesive with scarce tight junctions, and their cytoplasm contained numerous zymogen granules and filamentous inclusions. Although ACCs usually show expansive growth, the incidence of intraductal extension may be higher than previously considered. A few of the characteristic cytomorphological features described here may be useful for differential diagnosis of this tumor from malignant epithelioid neoplasms involving the large pancreatic ducts.

Acinar Cell Carcinoma of the Pancreas: A Literature Review and Update

Pancreatic acinar cell carcinoma is a rare tumour, accounting for only about 1 % of all pancreatic tumours. The long-term survival for patients with acinar cell carcinoma is significantly better than the long-term survival of patients with pancreatic adenocarcinoma. As no large series of patients with acinar cell carcinomas exist, our understanding of this disease comes mainly from small case series and case reports. Aggressive surgical resection with negative margins is associated with long-term survival in these more favourable pancreatic cancers. There are no clear treatment guidelines for patients in whom complete surgical resection with curative intent is not possible. Acinar cell carcinomas are chemoresponsive to agents that have activity against pancreatic adenocarcinomas and colorectal carcinomas because of the shared genetic alterations between these cancers. The role of neoadjuvant or adjuvant chemoradiotherapy remains unproven. The aim of this article is to present current knowledge on acinar cell carcinoma and comprehensive review of available literature.

[Two cases reports of pancreatic endocrine microadenoma incidentally found]

A 59-year-old male, was admitted to our hospital for a tumor of the pancreatic tail. Serum CEA and CA 19-9 levels were normal. Splenopancreasectomy found a desmoid tumour. A 69-year-old male was referred to our institution for chronic anemia and inflammatory syndrome with splenomegaly. Splenectomy showed an important splenic congestion and siderosis. Both patients had a type 2 diabetes mellitus. Furthermore, histological examination revealed pancreatic endocrine microadenomas. The two patients' postoperative course was unremarkable. Eleven and 24 months respectively after the diagnosis, the patients are alive and well, with no tumor recurrence.

CT imaging features of acinar cell carcinoma and its hepatic metastases

OBJECTIVE

To evaluate and describe the computed tomography features of pure acinar cell carcinoma (ACC) and its liver metastases.

METHODS

Thirty patients were evaluated. Two radiologists evaluated imaging findings for each tumor for size, location, internal density, enhancement, tumor calcifications, pancreatic, and common biliary ductal obstructions and metastases.

RESULTS

70 % were male. Fourteen tumors were located in the pancreatic head, 14 in the tail, one in the neck, and one in the uncinate process. Abdominal pain was the most common presenting symptom (93 %), 20 % had pancreatitis and 17 % had obstructive jaundice. The average tumor size was 7 cm, 97 % of tumors were solid, well circumscribed (73 %); isodense to normal pancreatic parenchyma (40 %) on the non-contrast study, hypodense on the arterial (47 %), and hypodense on the portal venous (37 %) phase. 30 % patients had pancreatic ductal dilation, 10 % had pancreatic ductal ingrowth, 6 % had calcifications, and 20 % had central necrosis, and 31 % (5/16) showed biliary ductal dilation. At presentation, 50 % had metastatic adenopathy and 40 % patients had liver metastases, which typically were well circumscribed, hypoattenuating to the hepatic parenchyma on all the phases of contrast enhancement and had a lobulated margin.

CONCLUSION

ACCs of the pancreas often present as large, well circumscribed, solid masses commonly in males. Despite their large size, they may not cause CBD obstruction.

Comparison of pancreatic acinar cell carcinoma and adenocarcinoma using multidetector-row computed tomography

AIM: To distinguish acinar cell carcinoma (ACC) from pancreatic adenocarcinoma (AC) by comparing their computed tomography findings.

METHODS: Patients with ACC and AC were identified on the basis of results obtained using surgically resected pancreatectomy specimens. The preoperative computer tomographic images of 6 acinar cell carcinoma patients and 67 pancreatic adenocarcinoma patients in 4 phases (non-contrast, arterial, portal venous, and delayed phase) were compared. The scan delay times were 40, 70, and 120 s for each contrast-enhanced phase. The visual pattern, tomographic attenuation value, and time attenuation curve were assessed and compared between AC and ACC cases using the χ² test, Wilcoxon signed-rank test, and Mann Whitney U test.

RESULTS: The adenocarcinomas tended to be hypodense in all 4 phases. The acinar cell carcinomas also tended to be hypodense in the 3 contrast-enhanced phases, although their computed tomographic attenuation values were higher. Further, 5 of the 6 acinar cell carcinomas (83%) were isodense in the non-contrast phase. The time attenuation curve of the adenocarcinomas showed a gradual increase through the 4 phases, and all adenocarcinomas showed peak enhancement during the delayed phase. The time attenuation curve of the acinar cell carcinomas showed peak enhancement during the portal venous phase in 4 cases and during the arterial phase in 2 cases. None of the 6 acinar cell carcinomas showed peak enhancement during the delayed phase.

CONCLUSION: The tumor density in the non-contrast phase and time attenuation curve pattern clearly differ between acinar cell carcinomas and adenocarcinomas, and multidetector-row computed tomography can thus distinguish these tumors.

Functional pancreatic acinar cell carcinoma extending into the main pancreatic duct and splenic vein

INTRODUCTION

Pancreatic acinar cell carcinoma (ACC) has several unique characteristics, such as its progression pattern, spreading into the pancreatic duct and large blood vessels, and its secretion of pancreatic exocrine enzymes, which induces a paraneoplastic syndrome.

CASE REPORT

A 79-year-old Japanese man, with medical history of chronic renal failure, was referred to our institution for the examination of his abdominal pain and hyperglycemia. Plain computed tomography demonstrated a mass lesion, 4 cm in diameter, in the body of pancreas. Abdominal ultrasonogram demonstrated a bulky, hypoechoic mass extending into the splenic vein. Multiple hepatic nodules were detected on suspicion of metastasis. Positron emission tomography using 18F-fluorodeoxyglucoase revealed the tumor extended towards the pancreatic head through the main pancreatic duct. We obtained the tumor tissues from the pancreatic body using endoscopic ultrasound-guided fine-needle aspiration biopsy. Pathological diagnosis, supported by immunohistochemistry, was that of an ACC. In the follow-up period, he complained of subcutaneous nodules and arthralgia on his lower legs. Serum and intra-articular lipase levels were elevated, 6,420 I/U and 594 I/U, respectively. Histology of the skin lesion at the knee joint showed necrotizing panniculitis with eosinophilic infiltration. The patient was treated with weekly gemcitabine, but succumbed to acute respiratory distress unexpectedly 2 months after the initial diagnosis.

Intraductal polypoid growth variant of pancreatic acinar cell carcinoma metastasizing to the intrahepatic bile duct 6 years after surgery: a case report and literature review

We present the first reported case of intraductal polypoid growth (IPG) variant of pancreatic acinar cell carcinoma (ACC) metastasizing to the intrahepatic bile duct. A 58-year-old Japanese woman had previously presented with obstructive jaundice and a 7.0 cm mass in the pancreatic head. She underwent biliary drainage for 2 months followed by pancreatectomy. Histological examination revealed a carcinoma with acinar pattern, immunohistochemically positive for trypsin, and acinar cell carcinoma was diagnosed. IPGs were prominent in the main pancreatic duct and its tributaries, extending into the intrapancreatic bile duct with tumor casts in the lumen. Imaging examinations 6 years later revealed a growing lesion within the intrahepatic bile duct. Needle biopsy examination suggested metastasis of ACC, and she underwent chemoradiation therapy and partial hepatectomy. Histological examination demonstrated ACC confined to the intrahepatic bile duct. The localization of metastasis and slow growth may indicate indolent biologic behavior of the IPG variant.

Pancreatic Cystic Tumors of Mucinous Type

This article presents the clinicopathologic characteristics and differential features of pancreatic mucinous tumors. These tumors, which correspond to the most frequent cystic neoplasms, are encountered with increasing frequency. They comprise the mucinous cystic neoplasms and the intraductal papillary mucinous neoplasms. These tumors are known to progress from dysplasia to invasive carcinoma. Thus, it appears important to distinguish them from other cystic neoplasms and non-neoplastic cysts.

Nonfunctioning pancreatic endocrine tumor with extension into the main pancreatic duct: report of a case

Pancreatic endocrine tumors (PETs) rarely involve the main pancreatic duct. We report a case of malignant nonfunctioning pancreatic endocrine tumor (NFPET) with prevalent intraductal growth. A 47-year-old woman was referred to us after ultrasonography at a routine health check showed diffuse swelling of the pancreas. Preoperative imaging showed a solid mass in the tail of the pancreas and a bulging intraductal mass in the main pancreatic duct. We performed total pancreatectomy because the tumor occupied almost the entire lumen of the main pancreatic duct. Histological examination confirmed well-differentiated endocrine carcinoma. We review reported cases of the intraductal growth of NFPETs and discuss the pathogenesis of these unusual tumors.

Acinar cell carcinoma of the pancreas: a rare tumor with a particular clinical and paraclinical presentation

Acinar cell carcinoma (ACC) of the pancreas is a rare tumor with an extremely low incidence rate. While the number of reported patients with ACC is relatively small, a long-term survival rate has been noted in patients with neuroendocrine differentiation. A 39-year-old woman visited our emergency department for upper gastrointestinal bleeding. Endoscopy indicated extrinsic compression of the posterior body of the stomach, together with a large, 10-cm, central ulcer covered with necrotic tissue. Abdominal computed tomography (CT) indicated a lesion that involved the whole of the pancreas, with a fistula in the stomach, which was suspected of being a degenerative intraductal papillary mucinous tumor of the pancreas. Magnetic resonance imaging (MRI) of the pancreas was performed, and the results further strengthened our suspicions by demonstrating the presence of cystic lesions and tumor buds. A total duodenopancreatectomy, including total splenectomy and gastrectomy, was performed, along with two independent Roux-en-Y anastomoses (one esojejunal and one hepaticojejunal). The tumor also had a wide opening in the stomach. The patient's postoperative course was marked by partial thrombosis of the portal vein, which was treated medically. Histopathological examination provided evidence of pancreatic ACC. The diagnosis of ACC should be considered in the presence of cutaneous lesions, which were absent in the case of our patient, and colonoscopy is also highly desirable because of the various forms associated with familial adenomatous polyposis. The prognosis, which includes a 5-year survival rate of 45%, in the population with an R0 resection is better than that for ductular adenocarcinoma, thus prompting the more aggressive management of this type of tumor.

Pancreatic acinar cell carcinomas with prominent ductal differentiation: Mixed acinar ductal carcinoma and mixed acinar endocrine ductal carcinoma

BACKGROUND

Pancreatic acinar cell carcinomas (ACCs) are clinically and pathologically distinct from pancreatic ductal adenocarcinomas (PDAs). Whereas endocrine differentiation has been well shown in ACCs, significant ductal components are rare. This paper reviews the clinicopathologic features of a series of ACCs with prominent ductal differentiation.

DESIGN

Cases of pancreatic ACCs with significant ductal differentiation were identified in the surgical pathology databases of 2 academic centers. Patient clinical information, gross and histologic features, and histochemical and immunohistochemical (IHC) results were recorded. Cases were tested for KRAS2 mutations.

RESULTS

Eleven cases were identified (10 men and 1 woman; age range 52 to 79 y). Four patients presented with jaundice. At last follow-up, 7 patients died of disease and 2 others had recurrences. Tumors measured between 2 and 5.5 cm and were ill-defined, nodular, and multilobulated. Ten were located in the head of the pancreas. All but 2 exhibited extrapancreatic invasion. All cases showed significant evidence of both acinar and ductal differentiation, estimated to be at least 25% of the neoplastic cells, and 3 cases in addition had endocrine differentiation in more than 25% of cells. Five cases were predominately acinar with intracellular and sometimes extracellular mucin ("mucinous acinar cell carcinoma" pattern). Six cases seemed more mixed with areas recapitulating typical PDAs whereas the other portions of the tumors seemed akin to typical acinar cell carcinomas ("combined acinar and ductal" pattern). IHC positive staining results were as: trypsin (92%), chymotrypsin (92%), monoclonal carcinoembryonic antigen (100%), CK19 (100%), B72.3 (73%), CA19.9 (73%), CD56 (18%), synaptophysin (36%), and chromogranin (36%). One case showed p53 over-expression aznd none showed DPC4/Smad4 loss. Two cases had KRAS2 mutations.

CONCLUSION

Despite the early embryologic divergence of acinar and ductal cell lineages, rare pancreatic tumors have both acinar and ductal differentiation, usually predominantly the former. The clinical course is highly aggressive.

Mixed acinar-endocrine carcinoma of the pancreas with intraductal growth into the main pancreatic duct: Report of a case

The patient was a 75-year-old asymptomatic man, in whom a tumor mass in the pancreatic tail had been found 6 months earlier. Computed tomography revealed a mass 7 cm in diameter, and an enhancement with contrast medium was observed at the periphery and partially inside the mass, but not in most parts of the tumor. Endoscopic retrograde cholangiopancreatography showed a filling defect in the main pancreatic duct. A distal pancreatectomy was performed because of the possibility of a malignant tumor. The tumor consisted of a lobular invasive growth component and a component with intraductal growth into the main pancreatic duct, and histologically the tumor cells had solid acinar to partially trabecular/tubular patterns. Trypsin (an acinic cell marker) expression was widely observed, followed by the expression of chromogranin A (an endocrine cell marker) in about 30% of the tumor cells. The tumor was diagnosed as mixed acinar-endocrine carcinoma according to the WHO classification.

Acinar cell carcinoma of the pancreas with intraductal growth: report of a case

Acinar cell carcinomas (ACCs) of the pancreas are rare neoplasms, accounting for approximately 1% of all exocrine pancreatic tumors. This type of tumor is known to be aggressive, although the survival rates are somewhat better than they are for ductal carcinoma. The tumor tends to present nonspecific symptoms. It occurs in older patients, and jaundice is infrequent. This report presents a case of ACC of the pancreas with intraductal papillary growth and lymph node metastasis.

Pancreatic acinar cell carcinoma: a multi-institutional study

INTRODUCTION

The presentation and outcome of patients with acinar cell carcinoma (ACC) of the pancreas compared to the more common ductal cell adenocarcinoma (DCA) may be distinct. This study combines the experience with ACC from multiple academic institutions to better understand its natural history and outcomes.

METHODS

This study is a multi-institutional retrospective review of patients with ACC.

RESULTS

Between 1988 and 2008, 17 patients were identified with pathologically confirmed ACC. Median age at presentation was 59 years. Common presenting symptoms were abdominal pain (60%), back pain (50%), and weight loss (45%). Fifteen patients underwent 16 operations: pancreaticoduodenectomy (nine), distal pancreatectomy (four), and exploratory laparotomy (three). Mean tumor size was 5.3 cm. American Joint Commission on Cancer tumor stages were stage I (two), stage II (eight), stage III (four), and stage IV (three). Overall, 1- and 5-year survival rates were 88% and 50%, respectively. In resected cases (13), 1- and 5-year survival rates were 92% and 53%, respectively. Median survival in resected cases was 61 months. This is in contrast to 1,608 patients with ductal cell adenocarcinoma who underwent resection identified from recent literature reports where the average median survival was only 24 months. There was no discernable difference in the outcomes of patients with ACC between United States and Germany patients.

CONCLUSION

Acinar cell carcinoma of the pancreas is rare and appears to have a presentation and outcome distinct from the more common pancreatic DCA. Based upon these data, the outcome of patients with ACC is superior to that of DCA.

Acinar cell carcinoma with prominent intraductal growth pattern: case report and review of the literature

Acinar cell carcinoma of the pancreas is rare, accounting for less than 1% of carcinomas arising in the exocrine pancreas. Patients are typically between the fifth and seventh decade of life and show a 2:1 male predominance. Symptoms tend to be nonspecific, and approximately 50% of the patients have metastases at the time of presentation. There have been recent case reports of acinar cell carcinoma showing both intraductal and/or papillary patterns of growth that could potentially be mistaken for intraductal neoplasia. The cases reported up to date presented as solitary nodules. The authors describe the first case of acinar cell carcinoma with both intraductal and tubuloglandular growth diffusely involving the pancreas. In addition, the authors review the published cases reporting acinar cell carcinoma with intraductal and/or papillary growth patterns.

Intraductal pancreatic neuroendocrine tumor

Intraductal lesions of the pancreas are usually due to intraductal papillary mucinous neoplasms and the less common intraductal tubular adenoma. Cases of acinar cell carcinoma within intraductal location have also been encountered recently. Pancreatic neuroendocrine tumors are rarely encountered within the main pancreatic duct. A 74-year-old male presented with non-specific abdominal symptoms and was found to have an obstructive lesion in the main pancreatic duct with associated chronic pancreatitis. A distal pancreatectomy was performed which revealed a solid and cystic tumor measuring 6 x 3 x 2 cm situated wholly within the main pancreatic duct. It formed an obstructing intraluminal polypoid lesion that resulted in surrounding chronic pancreatitis. Microscopic evaluation of the mass showed it to be a well-differentiated pancreatic neuroendocrine tumor with entrapped, non-malignant tubules. Intraductal pancreatic neuroendocrine tumors may occur in two settings. Firstly, and more commonly, there is a parenchymal-based tumor that then encroaches on and pushes into the main pancreatic duct. The less common scenario is of a primary intraductal location without a pancreatic parenchymal lesion. While an intraductal location of a pancreatic neuroendocrine tumor is rare, it should be borne in mind when confronted by an intraductal lesion in the pancreas.

Acinar cell carcinoma of the pancreas: an institutional series of resected patients and review of the current literature

INTRODUCTION

Acinar cell carcinoma (ACC) is a rare, malignant neoplasm with a generally poor prognosis. We report our institutional series of 14 patients with ACC to determine current guidelines for their evaluation and treatment.

MATERIALS AND METHODS

The Johns Hopkins pathology prospective database was reviewed from 1988 to 2006 to identify patients with pancreatic neoplasms possessing features of acinar cell differentiation. Retrospective review and follow-up was performed for each patient.

RESULTS

Fourteen patients with ACC were identified with a median age of 57 years. All patients presented with abdominal pain or discomfort with none showing evidence of lipase hypersecretion syndrome. Each patient underwent surgical resection, including nine pancreaticoduodenectomies and five distal pancreatectomies. Median tumor size was 3.9 cm with 12 patients found to have stage IIB disease or worse. Four patients underwent neoadjuvant chemoradiation. Eight of the fourteen patients developed recurrent disease. Overall median survival and disease-free survival were 33 and 25 months, respectively, as compared to a median survival of 18 months for pancreatic adenocarcinoma.

CONCLUSION

Acinar cell carcinomas are rare, aggressive neoplasms that are difficult to diagnose and treat. Operative resection represents the best first-line treatment. These lesions have a better prognosis than the more common pancreatic adenocarcinomas.

Application of immunohistochemistry to liver and gastrointestinal neoplasms: liver, stomach, colon, and pancreas

CONTEXT

Immunohistochemistry has become an integral component of the practice of pathology. Newer antibodies allow for increasingly precise diagnoses for tumors that previously could not be easily identified. Recently, immunohistochemical evaluations have begun to allow pathologists to actively assist in determining prognosis and even in selecting therapies.

OBJECTIVE

To summarize the usefulness of currently available immunostains for the study of liver and gastrointestinal system neoplasms and to make recommendations for panels of immunostains that can be particularly helpful.

DATA SOURCES

Information has been collected from recent literature as well as from personal experience and practice.

CONCLUSIONS

Many immunostains are now available for the practicing pathologist that allow for increasing accuracy in diagnosis of liver and gastrointestinal tract neoplasms. Panels of immunostains can be used to differentiate between various tumors and also to identify site of origin in the case of a metastatic neoplasm. Immunostains that allow for prognostic determinations and for guidance in the selection of chemotherapeutic agents can also be used by pathologists to assist in the management of patients with malignant tumors affecting the liver and gastrointestinal tract.

[Acinar cell carcinoma of the pancreas with predominant intraductal growth: report of a case]

Acinar cell carcinoma (ACC) of the pancreas accounts for approximately 1% of all exocrine pancreatic tumours. We report a rare form of ACC in a 66-year-old man. This tumour was revealed by epigastric pain and weight loss. Abdominal computed tomography showed a hypodense, well-demarcated, heterogeneous lesion, in the head of the pancreas, measuring 4.2 cm in diameter. There was a marked dilatation of the main pancreatic duct upstream, with tumour spreading within this duct. The diagnosis of ACC was made on the fine needle aspiration cytology performed during endoscopic ultrasound examination. On the pancreaticoduodenectomy specimen, the dilated main pancreatic duct (2.5 cm in diameter) was filled by an exophytic tumour. Histological examination showed an ACC, with predominant intraductal growth (main and accessory pancreatic ducts), with pancreatic parenchymal and duodenal invasion. Neuroendocrine markers were negative. To our knowledge, this is the second report of an ACC with predominant intraductal spread. These rare forms of ACC can be confused with intraductal papillary-mucinous neoplasms. In our report, fine needle aspiration cytology performed during endoscopic ultrasound examination was a valuable tool in the diagnostic assessment.

Pancreatic intraductal papillary-mucinous neoplasms: a new and evolving entity

For a long time, intraductal tumors of the pancreas were neglected because they were misdiagnosed as mucinous cystadenocarcinoma, ordinary ductal adenocarcinoma, or chronic pancreatitis. Only in recent years have they been recognized as clinical and pathological entities. Most common are the intraductal papillary-mucinous neoplasms. Although they show an adenoma-carcinoma sequence, they have proved to have a more favorable prognosis than ductal adenocarcinoma, when resected in a preinvasive state. Recently, it has become clear that they constitute a heterogeneous group with at least four subtypes. Their stratification reveals that the various intraductal papillary-mucinous neoplasm subtypes have different biological properties with different prognostic implications.

Acinar cell carcinoma of the pancreas: clinical analysis of 115 patients from Pancreatic Cancer Registry of Japan Pancreas Society

OBJECTIVES

Acinar cell carcinoma (ACC) of the pancreas is a rare tumor, and many aspects remain unclear because no large-scale clinical studies have been conducted.

METHODS

The present study investigated the clinical characteristics, treatment, and therapeutic outcomes of 115 patients registered in the Pancreatic Cancer Registry of the Japan Pancreas Society, and therapeutic plans were reviewed.

RESULTS

Although ACC has been associated with advanced stage and poor prognosis, this tumor was resectable in 76.5% of the patients, and the 5-year survival rate after resection was favorable, being 43.9%.

CONCLUSIONS

Confirming the diagnosis of ACC preoperatively is difficult, but this diagnosis should be kept in mind while planning surgery for ordinary pancreatic cancer. Once the diagnosis has been confirmed, a possibility of surgical resection should be pursued to achieve better prognosis. If ACC is unresectable or recurrent, chemotherapy is likely to prove useful. Multidisciplinary therapy centering on the role of surgery will need to be established.

Intraductal and papillary variants of acinar cell carcinomas: a new addition to the challenging differential diagnosis of intraductal neoplasms

The recognition and differential diagnosis of pancreatic intraductal neoplasms (IN) have gained importance in the past few years, as the incidence of these tumors (especially intraductal papillary mucinous neoplasms-IPMNs) have risen to >10% of pancreatic resections, and their significance as precursors of invasive cancer is better appreciated. Acinar cell carcinomas (ACCs) are typically solid tumors; however, we have recently encountered 7 ACCs with either intraductal growth and/or a papillary/papillocystic pattern that could be mistaken for IN. The clinicopathologic features of these cases were studied. Four patients were male and 3 female, with a mean age of 59 and mean tumor size of 4.9 cm (as compared with 10 cm in conventional ACCs). Only 1 patient had metastasis at the time of diagnosis (as opposed to 50% in usual ACCs). In 5 cases, the tumors had nodular growth of sheet-forming acinar cells, some of which were within ducts, as evidenced by the polypoid nature of the process, partial ductal lining, and presence of small tributary ducts in the walls. In 3 cases, the tumor had papillary and/or papillocystic growth, at least focally. All cases had cystic areas. No mucin was identified. All expressed trypsin. Markers of ductal differentiation were either absent or focal. A minor endocrine component was present in 3. The main histologic findings that distinguished these tumors from IPMNs were the more sheetlike nature of the nodules (rather than villous or arborizing papillae), cuboidal cells, overall basophilia of the cytoplasm, prominent nucleoli, apical granules, intraluminal crystals or pale, acidophilic secretions (enzymatic condensations), and lack of mucin. In conclusion, some ACCs show intraductal growth or exhibit papillary patterns, which can mimic IN, especially IPMNs. In such cases, attention to morphologic details described above, and immunohistochemistry are helpful. The clinical significance of this variant is difficult to determine; however, it appears that the tumors are relatively small and metastasis at presentation is less common than typically seen in ACCs (1/7 vs. 50%).

[Pancreatic intraductal tubular carcinoma: a sub-group of intraductal papillary-mucinous tumors or a distinct entity? A case report and review of the literature]

We report the case of a 67-year-old man presenting with an isolated 3 cm mass of the pancreatic tail revealed by weight loss. Distal pancreatectomy and splenectomy were performed. Microscopically, the tumor filled the main pancreatic duct, extending into the smaller ducts and was associated with a minor adenocarcinomatous invasive component. The intraductal tumor showed a cribriform pattern, atypical cells without mucus and a MUC1+, MUC2-, MUC5AC- phenotype, all characteristics of intraductal tubular carcinoma, a new entity described by Japanese authors. The differential diagnosis and its relationship with intraductal papillary-mucinous tumors are discussed.

Pancreatic acinar cell carcinoma extending into the common bile and main pancreatic ducts

Acinar cell carcinoma (ACC) of the pancreas is relatively rare, accounting for only approximately 1% of all exocrine pancreatic tumors. A 69-year-old man was found to have a mass lesion measuring approximately 4 cm in diameter in the pancreatic head on ultrasound, abdominal dynamic CT, and percutaneous transhepatic cholangiography. Magnetic resonance cholangiopancreatography showed defect of the lower common bile duct (CBD) due to obstruction by the tumor cast. Histopathologically, the pancreatic head tumor invaded the main pancreatic duct (MPD) and CBD with extension into the CBD in a form of tumor cast. The tumor cells consisted of a solid proliferation with abundant eosinophilic cytoplasm and round nuclei in an acinar and trabecular fashion. A 55-year-old man with upper abdominal pain and nausea, had a cystic lesion approximately 3 cm in size in the pancreatic tail on CT. Histopathologically, the tumor was encapsulated by fibrous capsule and had extensive central necrosis with solid areas in the tumor periphery, and invaded with extension into the MPD in a form of tumor cast. The tumor cells resembled acinar cells in solid growths. Two resected cases of ACC with unusual tumor extension into the CBD and the MPD, respectively, are reported.

[Intraductal neoplasms of the pancreas: cystic and common]

The most important of the generally rare intraductal tumors of the pancreas is the intraductal papillary-mucinous neoplasm (IPMN). In recent years this tumor type has been described in detail, and it was included in the WHO classification of 1996. IPMNs typically grow for a long time within the ducts, before approximately 50% of them eventually become invasive. Because of this feature the IPMNs are clearly distinct from ductal adenocarcinomas. Currently, IPMNs have advanced to the most commonly resected cystic tumor of the pancreas. Recent studies have shown that IPMNs may be distinguished into different types showing a different biology according to their mucin pattern.

[Acinar cell carcinomas and pancreatoblastomas: related but not the same]

Acinar cell carcinomas and pancreatoblastomas are malignant tumors of the pancreas, showing predominantly acinar differentiation characterized by the immunohistochemical expression of pancreatic enzymes. Histologically, they usually display acinar and/or solid patterns, but may occasionally also exhibit cystic structures. The key feature of pancreatoblastomas is the presence of squamoid corpuscles. Acinar cell carcinomas predominantly occur in adults, pancreatoblastomas in children. Both tumor types commonly show allelic losses on chromosome 11p and mutations in the APC/beta-catenin signaling pathway. Pancreatoblastomas, in contrast to acinar cell carcinomas, are potentially curable.

Acinar cell cystadenoma of the pancreas: a new entity?

This report describes a newly observed cystic lesion of the pancreas showing acinar cell differentiation. The patients affected by this lesion included seven women and three men (age range 16-66 years). In six patients, all of whom were female and all but one of whom suffered from abdominal pain, the cystic lesions (diameters, 4-15 cm) were detected by imaging techniques and subsequently removed. In four patients the cystic lesions were incidental findings. Eight lesions occurred as unifocal, unilocular or multilocular cysts in the head (n = 6) or tail (n = 2) of the pancreas. One lesion was bifocal (head and tail) and another involved the entire pancreas. The cysts were only rarely connected with the pancreatic duct system, but with acinar structures. Their lining cells expressed pancreatic enzymes and lacked any cellular atypia or proliferative activity (Ki67 index <1%). For a follow-up period of 6-84 months all patients remained alive and well. Although a nonneoplastic nature cannot be fully excluded, we propose that this lesion, composed of well-differentiated acinar cells, may represent the benign counterpart of the well-recognized acinar cystadenocarcinoma. We therefore suggest the term acinar cell cystadenoma.

Mucinous nonneoplastic cyst of the pancreas: a novel nonneoplastic cystic change?

Cystic lesions and neoplasms of the pancreas are uncommon, but they are of special interest because they can usually be cured by resection. During the last decade, the spectrum of these tumors has increased considerably. We present a series of five cystic lesions of the pancreas that differ from all categories described so far. The patients affected by these tumors were three men and two women (mean age, 57 y). Four lesions were unifocal and involved the head of the pancreas; one was multifocal and involved the pancreatic head and tail. Grossly, these tumors presented as unilocular or multilocular thin-walled cysts that contained turbid fluid, or, in two cases, blood, and lacked any communication with the duct system. Microscopically, the cysts were lined by cuboidal to columnar mucin-producing cells, supported by a small band of dense fibrous stroma. Immunocytochemically, the epithelial cells were positive for cytokeratins 7, 8, 18, 19, and 20 (except one), and Ca 19-9 but were negative for trypsin, CEA, synaptophysin, chromogranin A, calretinin, and alpha-inhibin. In four of the five lesions, the epithelial cells expressed MUC5AC, and in one of the five, MUC1. MUC2 and MUC6 were not expressed in any of the lesions. The stromal cells lacked the nuclear progesterone positivity that is typical of mucinous cystic neoplasms. During a mean follow-up period of 2 years, there were no recurrences or cases of malignant transformation after resection. The results suggest that these cystic lesions are distinct from mucinous cystic neoplasms, the most important entity in the differential diagnosis. Because they may represent a nonneoplastic cystic change of the pancreas, we propose the descriptive term mucinous nonneoplastic cyst for these tumors of unknown pathogenesis.