Acinar cell carcinoma of the pancreas with elevated serum alpha-fetoprotein levels: a case report and a review of 28 cases reported in Japan

Clinical characteristics and surgical outcomes of resectable acinar cell carcinoma of the pancreas-propensity score matching analysis with pancreatic ductal adenocarcinoma

BACKGROUND

Surgical resection is recommended for patients with resectable acinar cell carcinoma (ACC). The aim of this study was to investigate the clinical characteristics and surgical outcomes of resectable ACC in comparison to pancreatic ductal adenocarcinoma (PDAC).

METHOD

A retrospective analysis was performed on all patients who consecutively underwent radical resection with pathologically confirmed ACC and PDAC from December 2011 to December 2018. Clinicopathologic characteristics and follow-up information were analyzed. A 1:3 propensity score matching (PSM) method was used to minimize the bias between ACC and PDAC.

RESULTS

A total of 26 patients with ACC and 1351 with PDAC were included. Compared to PDAC, ACC tended to be larger (4.5 vs. 3.0 cm; p < 0.001) and more frequently located in the pancreatic body/tail (61.5% vs. 36.6%, p = 0.009), with lower total bilirubin levels, lower neutrophil lymphocyte ratio (NLR) levels and lower carbohydrate antigen 19-9 (CA19-9) levels and carcinoembryonic antigen (CEA) levels. There was no difference in postoperative morbidities in patients with ACC and PDAC. The median OS and RFS were longer in ACC when compared to PDAC (OS: 43.5 mo vs. 19.0 mo, p = 0.004; RFS: 24.5 mo vs. 11.6 mo, p = 0.023). After the 1:3 PSM, ACC remained to be a better histological type for OS (p = 0.024), but had comparable RFS with PDAC (p = 0.164).

CONCLUSION

Patients with ACC after radical resection had better OS than that with PDAC. However, ACC is also an aggressive tumor with a similar trend of RFS with PDAC after the matching, necessitating the multidisciplinary treatment for resectable ACC disease.

Pitfalls in the diagnosis of yolk sac tumor: Lessons from a clinical trial

Though outcomes for patients with recurrent/refractory malignant germ cell tumors (mGCTs) are poor, therapies targeting mTOR and EGFR inhibition have shown promise in vitro. We hypothesized that the combination of sirolimus and erlotinib will show activity in patients with recurrent/refractory mGCTs. Patients were enrolled in a prospective phase II clinical trial; central review of existing pathology specimens was performed. Of the five patients evaluated, two had their diagnoses revised to pancreatic acinar cell carcinoma and alpha-fetoprotein (AFP)-secreting gastric adenocarcinoma, respectively. Although mGCTs are common AFP-secreting neoplasms, recurrence or refractoriness to standard regimens should prompt histologic reevaluation for other diagnoses.

Mimics of hepatocellular carcinoma: a review and an approach to avoiding histopathological diagnostic missteps

Hepatocellular carcinoma (HCC) is one of the commonest carcinomas and leading causes of cancer-related death. Although, in patients with cirrhosis, radiologic diagnosis has improved significantly over the years, needle biopsy and histopathological assessment remains an important diagnostic modality. Most importantly, histopathological diagnosis is essential in patients with contending extrahepatic primaries, those with no known HCC risk factors, patients with ambiguous radiological features, and many other clinical contexts. Helpful features such as high serum alpha-fetoprotein (AFP) serologies are known to be present in many other tumor (including but not only HCC) and nontumor contexts and therefore not only lack sufficient diagnostic specificity for HCC but also create the potential to overlook non-HCC AFP-producing tumors, of which there are many. Therefore, using clinical examples and other examples from the medical literature, this review discusses several clinical and histological mimics of HCC and proffers an approach for practicing pathologists geared toward avoiding missteps.

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.

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.

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.

Tumor Markers in the Diagnosis, Monitoring and Therapy of Pancreatic Cancer: State of the Art

The present review focuses on the utility of serum tumor markers in screening, diagnosis, prognosis and monitoring of pancreatic cancer. Serum determination of all tumor markers studied offers no help in screening or early diagnosis of pancreatic cancer. For diagnosis, blood group-related antigens, in particular CA 19-9, are considered the best indicators of this neoplasm. However, as occurs with other glycoproteic tumor markers, the circulating levels of CA 19-9 are significantly influenced by jaundice, probably because its liver metabolism is reduced. Therefore, the finding of elevated CA 19-9 levels in jaundiced patients has to be evaluated with caution. Since pancreatic cancer recurrences are not susceptible to treatment, the clinical role of widespread use of tumor marker determination in follow-up programs is limited and calls for a critical evaluation.

Case Report of an Hepatoid Adenocarcinoma of the Stomach

Hepatoid adenocarcinoma (HAC) is a rare but important type of extrahepatic tumor that has a morphologic similarity to hepatocellular carcinoma, with production of α-fetoprotein in high amounts and a poor prognosis. Stomach is one of the organs in which HAC has been most commonly identified. We report a case of an old man with a polypoid mass in the prepyloric region. The microscopical aspects were suggestive for an undifferentiated adenocarcinoma, but the positive immunohistochemical staining for α-fetoprotein, α-1-antitrypsin, α-1-antichymotrypsin, and Hep Par1 were crucial for the final diagnosis of hepatoid adenocarcinoma of the stomach. Because of the poor prognosis for this type of tumor, correct and early-stage diagnosis of HAC is essential and long-term follow-up is required.

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.

Pancreatic acinar cell carcinoma with bilateral ovarian metastases, panniculitis and polyarthritis treated with FOLFIRINOX chemotherapy regimen. A case report and review of the literature

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor, with an estimated frequency of less than 1% of pancreatic malignancies. There are no prospective studies to guide diagnostic or therapeutic algorithms. We report the case of a 36 year-old woman, diagnosed of a pancreatic tumor with liver and peritoneal metastases that was initially managed as a neuroendocrine tumor with temozolomide and capecitabine. After two cycles a severely painful arthritis developed in her left ankle with panniculitis and extensive fat necrosis, and CT scan demonstrated progressive disease. Pathology of the primary was reassessed establishing the diagnosis of PACC. The patient started treatment with FOLFIRINOX regimen, achieving clinical benefit and disease stabilization. We also briefly reviewed the literature on this rare subtype of pancreatic tumor.

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.

Cytomorphologic and immunophenotypical features of acinar cell neoplasms of the pancreas

BACKGROUND

Acinar cell neoplasms of the pancreas are rare but when encountered, the diagnosis is often established based on cytology specimens. Diagnostic accuracy is important because acinar cell carcinomas are aggressive yet may mimic tumors with different outcomes and management.

METHODS

The authors identified all patients with a diagnosis of acinar cell neoplasm in the institutional database; assessed cytomorphology and immunocytochemistry for trypsin, chymotrypsin, synaptophysin, chromogranin A, and MIB-1; and compared all cytology and final histological diagnoses for diagnostic discrepancies.

RESULTS

Cytological features were described for 16 histologically proven malignant acinar cell neoplasms: acinar cell carcinoma (8 cases), mixed acinar-neuroendocrine carcinoma (6 cases), mixed acinar-ductal carcinoma (1 case), and pancreatoblastoma (1 case).The majority of aspirates from acinar cell cystadenomas were nondiagnostic or negative (5 of 6 cases; 83%). Acinar and neuroendocrine differentiation that was detected by immunocytochemistry in >20% of tumor cells was found to be correlated with mixed acinar-neuroendocrine carcinoma histology. Cytohistological correlation included 32 patients with 17 discordant diagnoses (53%). The following preoperative cytology diagnoses proved to be acinar cell neoplasms on resection: neuroendocrine tumor (5 cases), adenocarcinoma (5 cases), atypical ductal cells (2 cases), solid pseudopapillary neoplasm, and hepatocellular carcinoma. Three aspirates diagnosed as acinar cell carcinoma by cytology proved to be chronic pancreatitis (2 cases) and ductal adenocarcinoma (1 case).

CONCLUSIONS

Acinar cell carcinoma has a distinctive cytological appearance but is frequently misdiagnosed on cytology. Immunocytochemistry is useful for identifying acinar differentiation.

[A case of acinar cell carcinoma of pancreas, manifested by subcutaneous nodule as initial clinical symptom]

Pancreas acinar cell carcinoma (ACC) accounts for only 1-2% of pancreatic exocrine malignant tumor. The symptoms of patients with ACC are usually non-specific, for example the anorexia and weight loss. Patients may develop Schmid's triad including subcutaneous fat necrosis, polyarthritis, and eosinophilia. We reported a case of ACC which was manifested by subcutaneous nodule as initial clinical symptom. To our knowledge, this is the first reported case of ACC presenting as subcutaneous fat necrosis in Korea.

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.

Gastric choriocarcinoma admixed with an α-fetoprotein-producing adenocarcinoma and separated adenocarcinoma

We report a case of gastric choriocarcinoma admixed with an α-fetoprotein (AFP)-producing adenocarcinoma. A 70-year-old man was hospitalized for gastric cancer that was detected during screening by esophagogastroduodenoscopy (EGD). Initial laboratory data showed the increased serum level of AFP and EGD revealed a 5-cm ulcerofungating mass in the greater curvature of the gastric antrum. The patient underwent radical subtotal gastrectomy with D2 lymph node dissection and Billroth II gastrojejunostomy. Histopathological evaluation confirmed double primary gastric cancer: gastric choriocarcinoma admixed with an AFP-producing adenocarcinoma and separated adenocarcinoma. At 2 wk postoperatively, his human chorionic gonadotropin and AFP levels had reduced and six cycles of adjuvant chemotherapy were initiated. No recurrence or distant metastasis was observed at 4 years postoperatively.

Hepatoid adenocarcinoma of the stomach - a different histology for not so different gastric adenocarcinoma: a case report

Hepatoid adenocarcinoma is an extrahepatic tumor characterized by morphological similarities to hepatocellular carcinoma. Hepatoid adenocarcinoma of the stomach is a cancer with an extremely poor prognosis with few cases reported. Here, we describe a 75-year-old Spanish man referred to our hospital with a history of abdominal pain, general fatigue, anorexia and sickness. Initial study revealed anemia, and computed tomography scan and abdominal ultrasonography showed multiple metastases to the liver with hepatocellular carcinoma characteristics in a liver with no cirrhotic change. Further study included a serum level of alpha-fetoprotein (AFP), which resulted markedly elevated, and a conclusive esophagogastroduodenoscopy describing an elevated tumour growing through the cardia and gastroesophageal junction with foci of necrosis and haemorrhage. Gastric biopsies of the tumor revealed poorly differenciated adenocarcinoma, with hepatoid differentiation. After a diagnosis of AFP-producing hepatoid adenocarcinoma of the stomach with multiple liver metastases was made, pallitive total gastrectomy, without liver resection, was performed. Patient recovered well after surgery, and entered into a palliative systemich chemotherapy protocol. Although this illness is recognized as having poor prognosis, the patient remains alive 8 months after the operation. Accurate diagnosis of hepatoid adenocarcinoma of the stomach is important, and should be suspected under certain circumstances. We describe this rare case of hepatoid adenocarcinoma of the stomach, and review the literature concerning the clinicopathological aspects.

Curative resection of a primarily unresectable acinar cell carcinoma of the pancreas after chemotherapy

Background

Acinar cell carcinoma (ACC) represents only 1–2% of pancreatic cancers and is a very rare malignancy. At the time of diagnosis only 50% of the tumors appear to be resectable. Reliable data for an effective adjuvant or neoadjuvant treatment are not available.

Case presentation

A 65-year old male presented with obstructive jaundice and non-specific upper abdominal pain. MRI-imaging showed a tumor within the head of the pancreas concomitant with Serum-Lipase and CA19-9. During ERCP, a stent was placed. Endosonographic fine needle biopsy confirmed an acinar cell carcinoma. Laparotomy presented an locally advanced tumor with venous infiltration that was consequently deemed unresectable. The patient was treated with five cycles of 5-FU monotherapy with palliative intention. Chemotherapy was well tolerated, and no severe complications were observed. Twelve months later, the patient was in stable condition, and CT-scanning showed an obvious reduction in the size of the tumor. During further operative exploration, a PPPD with resection of the portal vein was performed. Histopathological examination gave evidence of a diffuse necrotic ACC-tumor, all resection margins were found to be negative. Eighteen months later, the patient showed no signs of recurrent disease.

Conclusion

ACC responded well to 5-FU monochemotherapy. Therefore, neoadjuvant chemotherapy could be an option to reduce a primarily unresectable ACC to a point where curative resection can be achieved.

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.

Pancreatic acinar cell carcinoma with excessive alpha-fetoprotein expression

We report a case of acinar cell carcinoma of the pancreas associated with excessively elevated levels of serum alpha-fetoprotein (>32,000 ng/ml). Abdominal computed tomography scan revealed a large pancreatic mass with infiltration of the splenic artery. Because of inoperability, palliative combination chemotherapy with gemcitabine and mitomycin C was administered. This regimen was associated with clinical improvement and dramatic decreases in both tumor size and serum alpha-fetoprotein. However, the patient died 7 months later from acute severe cardiac failure.

Nonductal neoplasms of the pancreas

Although the majority of pancreatic neoplasms are infiltrating ductal adenocarcinomas or other neoplasms with ductal differentiation, neoplasms with acinar, endocrine, mixed, or uncertain differentiation constitute a diverse and distinctive group. The most common and best-characterized nonductal neoplasms are pancreatic endocrine neoplasm, acinar cell carcinoma, pancreatoblastoma, and solid pseudopapillary neoplasm. This review details the clinical and pathologic features of these nonductal neoplasms, highlighting diagnostic criteria including the use of specific immunohistochemical stains to define the cellular differentiation of the neoplasms.

Successful resection of a liver metastasis from AFP-producing pancreatic cancer resulting in long-term survival: a case report and review of literature

The prognosis of patients with alpha-fetoprotein (AFP)-producing pancreatic cancer is generally very poor. We, however, present a case of a 33-year-old man who survived AFP-producing pancreatic cancer and its metachronous liver metastasis. The patient had undergone a curative total pancreatectomy for AFP-producing pancreas head cancer invading to the tail, which was postoperatively confirmed by immunohistochemical staining of the resected specimen. At 1 year and 4 months after the operation, the serum AFP level was elevated to 26 ng/mL, and a 2.6 cm-sized mass was found in the lateral segment of the liver. He underwent lateral segmentectomy, and the tumor was histopathologically diagnosed as having metastasized from the AFP-producing pancreatic cancer removed earlier. The patient is doing well 8 years and 5 months after resecting the liver metastasis, with no signs of recurrence. This case suggests that surgery may also be a treatment of choice for patients with liver metastasis from AFP-producing pancreatic cancer, particularly for those with a metachronous and solitary tumor. It should be remembered that some pancreatic cancers produce AFP and that monitoring of postoperative serum AFP levels in such cases will be useful for early detection of recurrence and selection of appropriate surgical intervention.

[Alpha-fetoprotein-producing poorly differentiated gastric adenocarcinoma: hepatoid carcinoma?]

We report the case of a 42-Year-old man with a poorly differentiated gastric cancer revealed by a very high level of serum alpha-fetoprotein-protein, associated with liver metastasis, and treated by chemotherapy. We discuss the possible diagnosis of hepatoid carcinoma.

Acinar cell carcinoma of the pancreas: clinical and computed tomography manifestations

PURPOSE

Acinar cell carcinoma (ACC) is a subtype of pancreatic neoplasm sufficiently rare that its imaging has not been fully analyzed. The purpose of this article is to present the computed tomography (CT) appearance of ACC of the pancreas.

METHODS

Clinical data and CT studies of 10 patients (7 male and 3 female) with pathologically proven ACC of the pancreas were reviewed. Among the CT features emphasized were the presence of a well-defined enhancing capsule, foci of internal calcification, intratumoral hemorrhage, presence of a central hypodense area, and degree of contrast enhancement.

RESULTS

The presenting symptoms of ACC of the pancreas were nonspecific. An elevated serum level of alpha-fetoprotein, carcinoembryonic acid, and CA 19-9 was noted in 2 (20%), 1 (10%), and 3 (30%) patients, respectively. The tumor locations were in the uncinate process in 4 (40%), in the head and neck in 2 (20%), in the body in 1 (10%), and in the tail in 3 (30%) patients. The average tumor size was 7.2 cm (range: 3.3-18 cm). A well-defined enhancing capsule, internal foci of calcification, and intratumoral hemorrhage appeared in 6 (60%), 5 (50%), and 0 tumors, respectively. Eight (80%) tumors had a central hypodense area; of these, 4 (40%) tumors exhibited a hypodense area greater than 50% of the tumor. During dynamic CT in 8 patients, 6 tumors showed early arterial (EA) enhancement and persisted into the portal venous (PV) phase, whereas the other 2 tumors revealed enhancement in the EA phase and washout in PV phase.

CONCLUSION

Acinar cell carcinoma typically presents as a sizable pancreatic mass with a well-defined enhancing capsule and internal calcifications. Significant central hypodensity is frequently present. Recognition of these features can provide clues to the CT diagnosis of ACC.

Carcinoma of the stomach with hepatocyte differentiation (hepatoid adenocarcinoma)

A case of hepatoid adenocarcinoma of the stomach is reported, and the literature is reviewed. The stomach is one of the most common sites in which hepatoid adenocarcinomas have been detected. Of the 59 cases reviewed from the literature (including the current case), a 2:1 male predominance was noted, and the serum alpha-fetoprotein level was almost always increased. All patients were adults, and most had evidence of metastases at the time of resection. Prognosis seems less favorable than that associated with the more common intestinal type of adenocarcinoma of the stomach. Hepatoid adenocarcinomas typically show periodic acid-Schiff-positive, diastase-resistant intracytoplasmic globules, which are demonstrated to be positive with antibodies to alpha-fetoprotein. The tumor cells resemble liver cells, and rare cases, including our own, have evidence of bile production. In our case, messenger RNA for albumin, unique to liver cells, was demonstrated by in situ hybridization of the tumor cells.

Alpha fetoprotein-producing acinar cell carcinoma of the pancreas showing multiple lines of differentiation

An alpha fetoprotein (AFP)-producing tumour occurring in the head of the pancreas of a 30-year-old woman is reported. Histological examination revealed a markedly solid proliferation of tumour cells with prominent nucleoli and occasional luminal structures, some of which contained mucinous material stained with mucicarmine and alcian blue. No squamoid corpuscles were recognized. Immunohistochemistry showed intense positivity for lipase trypsin, and AFP basically, and single cells were also positive for carcino-embryonic antigen, CA19-9, synaptophysin and neuron-specific enolase. Pancreatic hormone-positive cells were absent. Electron microscopical examination revealed numerous granules of variable sizes in the tumour cells, which were considered to be zymogen. The tumour is an acinar cell carcinoma with multi-directional differentiation including the ability to produce AFP. Among AFP-positive pancreatic tumours, acinar cell carcinoma and pancreatoblastoma seem to be the most frequent.

Use of lectins as diagnostic and therapeutic tools for cancer

Within the past few years, lectins have become a well-established means for understanding varied aspects of cancer and metastasis. Evidence is now emerging that lectins are dynamic contributors to tumor cell recognition (surface markers), cell adhesion and localization, signal transduction across membranes, mitogenic stimulation, augmentation of host immune defense, cytotoxicity, and apoptosis. To advance understanding of these lectin-dependent processes, attempts are being made to discover new lectins that have one or more of these functions and to develop lectin- (or glycoconjugate-) based tools that could be used to home in on tumor cells. This review will summarize current research on the lectins and recent advances in the development of lectin-based diagnostic and therapeutic tools for cancer. Additionally, the future potential of lectin-based diagnosis and therapy is discussed.

Acinar cell carcinoma of the pancreas. Report of three cases

Pancreatic acinar cell carcinoma is a rare neoplasm (comprising about 1% of pancreatic tumours). We studied three cases (61-year-old female; 42-year-old male; 57-year-old male), whose survival after diagnosis ranged from 1 year 2 months to 6 years 8 months. There were widespread metastases in each case. The tumours had acinar, trabecular and solid growth patterns. By immunohistochemistry, pancreatic acinar cell markers including carboxyl ester lipase, pancreatic secretory trypsin inhibitor and pancreatic phospholipase A2 (group I PLA2) gave a strong positive reaction in all three cases. By electron microscopy, zymogen granules were seen in the cytoplasm of the tumour cells. Immunostaining for prostate-specific antigen was positive in all three cases. Above-normal concentrations of pancreatic PLA2 were measured in the serum of one patient and the values decreased during chemotherapy concomitantly with the reduction in the size of the tumour mass. In conclusion, immunohistochemical demonstration of the secretory products of acinar cells including the new marker pancreatic PLA2 is useful in the differential diagnosis of pancreatic acinar cell carcinoma. Determination of the concentration of pancreatic group I PLA2 in serum may be helpful in the evaluation of therapy.