Pancreatoblastoma: a histochemical and immunohistochemical analysis

Pancreatoblastoma in children: EXPeRT/PARTNER diagnostic and therapeutic recommendations

Pancreatoblastoma (PBL) is a rare malignant epithelial neoplasm that affects typically young children. Signs related to advanced upper-abdominal tumor accompanied by elevated serum α-fetoprotein levels in a young child suggest PBL, however histopathological confirmation is mandatory. The mainstay of the treatment is a complete surgical resection. Unresectable and/or metastatic PBL may become amenable to complete delayed surgery after neoadjuvant chemotherapy. This manuscript presents the international consensus recommendations for the diagnosis and treatment of children with PBL, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the EU-funded PARTNER (Paediatric Rare Tumors Network - European Registry) project.

Pancreatoblastoma With Metastatic Retroperitoneal Lymph Node and PET/CT

A previously healthy 4-year-old girl presented with petechial rash and low platelet count. There were no other symptoms. On abdominal ultrasound, a 4.7-cm heterogeneous mass was demonstrated anterior to the left kidney. An abdominal MRI subsequently performed demonstrated a heterogeneously enhancing mass at the same location extending to the pancreas and spleen. A surgical biopsy of the mass was obtained. Pathology reported a malignant epithelioid neoplasm consistent with pancreatoblastoma. The mass demonstrated intense FDG uptake on PET and an FDG avid retrocaval lymph node.

Clinical analysis of childhood pancreatoblastoma arising from the tail of the pancreas

Pancreatoblastoma is a rare pancreatic tumor. In this study, 3 cases of childhood pancreatoblastoma that arise from the tail of the pancreas were reported. Abdominal pain and vomiting were observed in 1 case considering the huge size of the tumor. The other 2 patients, who were previously well, complained of a mass in the abdomen after a casual physical examination. Elevated serum α-fetoprotein levels were noted in all cases. Imaging findings indicated a well-defined heterogeneous large mass in the left retroperitoneal space. Exploratory laparotomy revealed a large mass, arising from the tail of the pancreas. Surgery alone with complete excision of the masses was performed. Immunohistochemical staining showed that only α-fetoprotein was positive in all cases. All of these 3 cases have a good outcome in the follow-up without adjuvant chemotherapy. These data suggest that the diagnosis of pancreatoblastoma is difficult and should be suspected at palpation of an abdominal mass. α-Fetoprotein may serve as a tumor marker for preoperative diagnosis and postoperative recurrence. Pancreatoblastoma arising from the tail of the pancreas is a curable tumor, and adjuvant chemotherapy may not be necessary if the tumor can be excised completely.

Cushing's syndrome in a child with pancreatic acinar cell carcinoma

A case of pancreatic acinar cell tumor (ACC) is presented in a 10-year-old boy. The tumor manifested clinically with Cushing's syndrome, high serum adrenocorticotropic hormone (ACTH) and cortisol concentrations. In addition, excessive serum levels of alpha-fetoprotein (AFP) were detected. Surgical resection was not possible due to retroperitoneal invasion. Biopsy of the mass showed a solid, poorly differentiated ACC of the pancreas. Periodic acid Schiff positive cytoplasmic granules, trypsinogen, keratins, alpha-1-antitrypsin, and AFP were identified in the tumor cells. Electron microscopy demonstrated zymogen granules as well as isolated dense core granules. Using immunochemiluminometric assay, a high quantity of ACTH was found in the fresh frozen tumor extract. ACTH, chromogranin A, and corticotropin-releasing factor were identified only in a few cells by immunohistochemistry. Combined radiochemotherapy was temporarily effective in reducing the tumor mass and serum AFP. Serum ACTH and cortisol levels dropped progressively and definitively to normal values after chemotherapy, and the Cushing's syndrome subsided. Two years later, the patient died with metastatic disease. The presented case of ACC is interesting due to high serum AFP values and ectopic ACTH secretion resulting in Cushing's syndrome.

Clinico-pathological features of a series of 11 oncocytic endocrine tumours of the pancreas

Oncocytic changes may occur very infrequently in neuroendocrine tumours. To estimate the prevalence, pathological features and clinical behaviour of oncocytic endocrine tumours of the pancreas, we reviewed a series of 227 lesions from two institutions. Eleven cases with predominant oncocytic features were selected, representing 4.85% of the whole series. The morphological features and immunophenotype of such tumours did not differ from conventional endocrine pancreatic tumours, except for the presence of abundant eosinophilic and granular cytoplasm. Anti-mitochondrial antigen was positive in all cases tested, and by electron microscopy, numerous mitochondria were observed in the cytoplasm of tumour cells. The majority of cases were nonfunctioning, and in most cases, pathologic signs of malignancy, leading to a diagnosis of endocrine carcinoma, were observed. In addition, the three nonmalignant cases matched the criteria of well-differentiated tumours of uncertain malignant potential. Nearly 50% of the cases were clinically aggressive, and lymph node and liver metastases were present at the time of diagnosis in a minority of cases. Therefore, oncocytic endocrine pancreatic tumours represent a peculiar morphological and clinical variant characterised by frequent hormonal inactivity and malignant behaviour, which should be considered in the differential diagnosis, especially when dealing with a metastatic lesion.

Radiolabeled peptides in oncology: role in diagnosis and treatment

There has been an exponential growth in the development of radiolabeled peptides for diagnostic and therapeutic applications in the last decade. The automated means of synthesizing these compounds in large quantities and the simplified methods of purifying, characterizing, and optimizing them have kindled attention to peptides as carrier molecules. These new techniques have accelerated the commercial development of radiolabelled peptides, which has provided additional radiopharmaceuticals for the nuclear medicine community. Peptides have many key properties including fast clearance, rapid tissue penetration, and low antigenicity, and can be produced easily and inexpensively. However, there may be problems with in vivo catabolism, unwanted physiologic effects, and chelate attachment. Radiolabeled peptides have made their greatest impact in the management of relatively rare neuroendocrine malignancies. Indeed, Indium-111 ((111)In)-pentetreotide ((111)In-DTPA-octreotide, Octreoscan), which binds to somatostatin receptors (SSTRs), has become the diagnostic 'gold standard' in these diseases. However, (111)In-pentetreotide has been less successful in the diagnosis of other more prevalent diseases in which SSTRs are upregulated. Technetium-99m (99mTc)-depreotide (NeoTect), a 99mTc-labeled SSTR-analog, could have wider impact since it has high sensitivity and specificity for lung cancer lesion detection. However, this impact may be minimized by the increased availability of positron emission tomography imaging with Fluorine-18 (18F)-flourodeoxyglucose, which has similar sensitivity and specificity for lesion identification in this disease, and is currently more widely used. The receptors for bombesin, alpha-melanocyte-stimulating hormone, neurotensin, and the integrin alpha(v)beta3, are under active investigation as targets for radiolabelled peptides, but are still in the pre-clinical stage. Compounds directed at the cholecystokinin-B/gastrin receptor have shown promising results in clinical trials in humans. Radiolabelled peptide therapy is usually indicated for patients with widespread disease that is not amenable to focused radiation therapy or is refractory to chemotherapy. Phase I/II studies using various radiolabelled peptides (including (111)In-pentetreotide, Yttrium-90 [90Y]-DOTA-Phe1-Tyr3-octreotide, 90Y-DOTA-lanreotide, and Lutetium-177 [177Lu]-DOTA-octreotate) for the treatment of patients with neuroendocrine malignancy are in progress. Over 400 patients have been treated, and the response rate has ranged from 60% to 75%, although few patients have had a complete response. Patients have been given individual doses ranging from 2 to 11 GBq with a slow infusion every 4-8 weeks (up to 12 times). The kidney is the dose-limiting organ and most patients experience a transient decline in blood cell counts. A concomitant infusion of an amino acid mixture can reduce kidney toxicity and increase the effective tumor dose. Other peptides currently under investigation, some of which have shown promising results, include Rhenium-188 (188Re)-P2045 and 90Y-alpha(v)beta3 antagonist.

Diagnosis, treatment and outcome of pancreatoblastoma

BACKGROUND

Pancreatoblastoma is a rare tumour mainly presenting in childhood but also in adults.

OBJECTIVES

The aim was to determine the clinical course of pancreatoblastoma by an analysis of reported cases.

METHODS

Patients with pancreatoblastoma were identified from Medline and combined with patients identified from the Royal Liverpool University Hospital.

RESULTS

There were 153 patients with a median (range) age at presentation of 5 (0-68) years and a male:female ratio of 1.14:1. The most frequent site was the head of pancreas (48/123, 39%). The median and 5-year (95% CI) survival rates were 48 months and 50% (37-62%) respectively. At presentation there were 17 (17%) out of 101 patients with metastases, the liver being the commonest site (15/17, 88%). On univariate analysis, factors associated with a worse prognosis were synchronous (p = 0.05) or metachronous metastases (p < 0.001), non-resectable disease at presentation (p < 0.001) and age > 16 years at time of presentation (p = 0.02). On multivariate analysis, resection (p = 0.006) and metastases post-resection (p = 0.001) but not local recurrence influenced survival.

CONCLUSIONS

Pancreatoblastoma is one of the pancreatic tumours with a relatively good prognosis. The treatment of choice is complete resection with long-term follow-up aiming to treat any early local recurrence or metastasis.

Distinctive molecular genetic alterations in sporadic and familial adenomatous polyposis-associated pancreatoblastomas : frequent alterations in the APC/beta-catenin pathway and chromosome 11p

Pancreatoblastomas are unusual malignant neoplasms of the pediatric pancreas that may also rarely affect adults. The molecular pathogenesis of pancreatoblastomas is unknown. They are clinicopathologically distinct from adult pancreatic ductal adenocarcinomas, but their occasional occurrence in patients with Beckwith-Wiedemann syndrome and the case presented here of a pancreatoblastoma in an adult patient with familial adenomatous polyposis (FAP) suggests that they might bear a genetic similarity to other infantile embryonal tumors such as hepatoblastomas. We analyzed a series of nine pancreatoblastomas for mutations common to other embryonal malignancies including somatic alterations in the adenomatous polyposis coli (APC)/beta-catenin pathway and chromosome 11p, using immunohistochemistry for beta-catenin, 5q and 11p allelic loss assays, and direct DNA sequencing of exon 3 of the beta-catenin gene and the mutation cluster region of the APC gene. In addition, we analyzed the pancreatoblastomas for alterations found in adult-type pancreatic ductal adenocarcinomas including mutations in the K-ras oncogene and the p53 and DPC4 tumor suppressor genes, using direct DNA sequencing of exon 1 of K-ras and immunohistochemistry for p53 and Dpc4. Allelic loss on chromosome 11p was the most common genetic alteration in pancreatoblastomas, present in 86% (six of seven informative cases). Molecular alterations in the APC/beta-catenin pathway were detected in 67% (six of nine), including five neoplasms with activating mutations of the beta-catenin oncogene and the one FAP-associated tumor with biallelic APC inactivation (germline truncating mutation combined with loss of the wild-type allele); seven neoplasms showed abnormal nuclear accumulation of beta-catenin protein. In contrast, loss of Dpc4 protein expression was present in only two cases (one diffuse and one focal), and no alterations in the K-ras gene or p53 expression were detected. Our findings indicate that pancreatoblastomas are genetically distinct from the more common pancreatic ductal adenocarcinomas, but bear a close molecular pathogenesis to hepatoblastomas. In addition, pancreatoblastoma may represent an extracolonic manifestation of FAP.

Fine-needle aspiration cytology of pancreatoblastoma

Pancreatoblastoma is a rare pancreatic neoplasm seen most commonly in the pediatric age group. We report on the aspiration cytology and immunohistochemical findings of a pancreatoblastoma in a 16-yr-old male.

Mesenchymal tumors of the pancreas: CT findings

This article reviews the CT imaging features of the most frequent mesenchymal tumors of the pancreas and stresses important distinctive patterns that may help distinguish specific entities. Various neoplasms (lymphangioma, lipoma, teratoma, pancreatoblastoma, schwannoma, neurofibroma, lymphoma, and sarcoma) are reviewed, with key differential points (structure, fatty and water densities, calcification, pattern of contrast enhancement, vascularization, and necrotic or regressive changes) emphasized. In addition, epithelial tumors are considered in the differential diagnosis.

Pancreatoblastoma: imaging findings in 10 patients and review of the literature

PURPOSE

To describe the features of pancreatoblastoma at magnetic resonance (MR) imaging, computed tomography (CT), and ultrasonography (US).

MATERIALS AND METHODS

Imaging and surgical findings in 10 patients (age range, 2-20 years; mean age, 6.8 years) with pathologically proved pancreatoblastoma were reviewed for tumor size, organ of origin, definition and quality of tumor margins, tumor heterogeneity, calcification, enhancement, ascites, biliary and/or pancreatic ductal dilatation, local invasion, adenopathy, vascular invasion, vascular encasement, metastases, and signal intensity on MR images. Results from 10 CT, seven US, and three MR imaging examinations were reviewed.

RESULTS

Five of the 10 tumors were pancreatic; four others appeared to be pancreatic or hepatic. Most had well-defined margins (nine of 10), were heterogeneous (nine of 10), and enhanced (10 of 10). Other findings included calcification (two of 10), biliary and pancreatic ductal dilatation (one of 10), and ascites (three of 10). Hepatic (two patients) and pelvic (two patients) metastases were present. Adenopathy (two patients) and vascular invasion (one patient) were not identified radiologically. Tumors had low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images.

CONCLUSION

Pancreatoblastoma is typically a heterogeneous tumor with well-defined margins that may appear to arise from the pancreas or liver. It may behave aggressively, with localized vascular or bowel invasion or with widespread metastatic disease. Although it is rare, it should be considered in the differential diagnosis of an upper abdominal mass in a child.