Intraductal growing acinar cell carcinoma of the pancreas

Clinical characteristics and treatment analysis of pancreatic acinar cell carcinoma: A single institutional comparison to pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic acinar cell carcinoma (PACC) is a rare malignancy that accounts for less than 1% of primary pancreatic neoplasms. Currently, the lack of large-scale clinical studies limits our understanding of PACC. The aim of this study was to investigate the clinical characteristics and prognosis of PACC.

METHODS

In a retrospective analysis, 52 patients with PACC and 355 patients with pancreatic ductal adenocarcinoma (PDAC) who underwent surgical interventions were evaluated. Clinical characteristics and treatment outcomes were compared between the two groups.

RESULTS

The mean age was lower for patients with PACC than for those with PDAC (mean: 50.8 ± 10.9 versus 59.4 ± 10.9 years; p < 0.001). Except for alpha-fetoprotein (AFP), tumour markers were also lower in the PACC group than the PDAC group. In regard to tumour characteristics, maximum diameters of the primary tumour [median (range): 5.0 cm (1.0-18.2 cm) versus 3.5 cm (0.6-15.0 cm); p < 0.001] and hepatic metastatic lesions [6.7 cm (1.5-12.6 cm) versus 1.2 cm (0.3-3.3 cm); p < 0.001] were larger in patients with PACC than patients with PDAC, but vascular invasion [23.1% (12/52) versus 35.5% (126/355); p = 0.044] and perineural invasion [7.7% (4/52) versus 56.1% (199/355); p < 0.001] were more common in patents with PDAC than in patients with PACC. For treatment, radical resection was performed in 57.7% of patients with PACC, which increased the 5-year survival rate to 31.8%. In regard to prognosis, the 5-year survival rate was 21.4% for PACC and 9.7% for PDAC (p < 0.0001).

CONCLUSIONS

PACC is more indolent than PDAC, which makes early diagnosis more difficult. Although the stage may be advanced at diagnosis, the overall survival (OS) of PACC is much better than that of PDAC, and the prognosis greatly improves after radical resection.

Computed tomography features of acinar cell carcinoma of the pancreas

PURPOSE

To report the computed tomography (CT) features of pancreatic acinar cell carcinoma (ACC) and identify CT features that may help discriminate between pancreatic ACC and pancreatic ductal adenocarcinoma (PDA).

MATERIALS AND METHODS

The CT examinations of 20 patients (13 men, 7 women; mean age, 66.5±10.7 [SD] years; range: 51-88 years) with 20 histopathologically proven pancreatic ACC were reviewed. CT images were analyzed qualitatively and quantitatively and compared to those obtained in 20 patients with PDA. Comparisons were performed using univariate analysis with a conditional logistic regression model.

RESULTS

Pancreatic ACC presented as an enhancing (20/20; 100%), oval (15/20; 75%), well-delineated (14/20; 70%) and purely solid (13/20; 65%) pancreatic mass with a mean diameter of 52.6±28.0 (SD) mm (range: 24-120mm) in association with visible lymph nodes (14/20; 70%). At univariate analysis, well-defined margins (Odds ratio [OR], 7.00; P=0.005), nondilated bile ducts (OR, 9.00; P=0.007), visible lymph nodes (OR, 4.33; P=0.028) and adjacent organ involvement (OR, 5.67; P=0.02) were the most discriminating CT features to differentiate pancreatic ACC from PDA. When present, lymph nodes were larger in patients with pancreatic ACC (14±4.8 [SD]; range: 7-25mm) than in those with PDA (8.8±4.1 [SD]; range: 5-15mm) (P=0.039).

CONCLUSION

On CT, pancreatic ACC presents as an enhancing, predominantly oval and purely solid pancreatic mass that most frequently present with no bile duct dilatation, no visible lymph nodes, no adjacent organ involvement and larger visible lymph nodes compared to PDA.

Imaging features of undifferentiated carcinoma of the pancreas

INTRODUCTION

The purpose of this retrospective study was to evaluate imaging features of undifferentiated carcinoma of the pancreas.

METHODS

The study group included eight patients with surgically resected undifferentiated carcinoma of the pancreas. Multidetector-row computed tomography (MDCT, n = 8) and magnetic resonance imaging (MRI, n = 6) findings were retrospectively reviewed.

RESULTS

On MDCT, all eight cases were hypovascular with upstream main pancreatic duct (MPD) dilatation, and only 1 showed exophytic growth. Five cases (62.5%) showed necrosis/cystic change, and calcification was observed in two cases (25%). Calcification reflected tumour osteoid components. On MRI, haemorrhage and hemosiderin were observed in 4 of 6 (66.7%) cases. In addition, tumour thrombus in the splenic vein (n = 1) and intraductal tumour growth in the MPD (n = 2) were pathologically identified, although imaging studies only revealed 1 of these latter cases.

CONCLUSION

Undifferentiated carcinoma of the pancreas may present as a tumour with haemorrhagic necrosis. Coexistence of calcification, intraductal tumour growth in the MPD and tumour thrombus may support the imaging diagnosis of this entity.

MR imaging features of pancreatic acinar cell carcinoma

PURPOSE

This study aimed to report the magnetic resonance imaging (MRI) features of acinar cell carcinoma (ACC) of the pancreas including diffusion-weighted MRI findings.

MATERIALS AND METHODS

The MRI examinations of five patients (3 men, 2 women; median age, 61years) with histopathologically proven ACC of the pancreas were retrospectively reviewed. MR images were analyzed qualitatively (location, shape, homogeneity, signal intensity, vascular involvement and extrapancreatic extent of ACC) and quantitatively (tumor size, apparent diffusion coefficient [ADC] and normalized ADC of ACC).

RESULTS

All ACC were visible on MRI, presenting as an oval pancreatic mass (5/5; 100%), with moderate and heterogeneous enhancement (5/5; 100%), with a median transverse diameter of 43mm (Q₁, 35; Q₃, 82mm; range: 30-91mm). Tumor capsule was visible in 4/5 ACC (80%) and Wirsung duct enlargement in 2/5 ACC (40%). On diffusion-weighted MRI, all ACC (5/5; 100%) were hyperintense on the 3 b value images. Median ADC value of ACC was 1.061×10^-3mm²/s (Q₁, 0.870×10^-3mm²/s; Q₃, 1.138×10^-3mm²/s; range: 0.834-1.195×10^-3mm²/s). Median normalized ADC ratio of ACC was 1.127 (Q₁, 1.071; Q₃, 1.237; range: 1.054-1.244).

CONCLUSIONS

On MRI, ACC of the pancreas presents as a large, oval pancreatic mass with moderate and heterogeneous enhancement after intravenous administration of a gadolinium chelate, with restricted diffusion and a median ADC value of 1.061×10^-3mm²/s on diffusion-weighted MRI. Further studies however are needed to confirm our findings obtained in a limited number of patients.

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.

Systematic Review and Case Series Report of Acinar Cell Carcinoma of the Pancreas

BACKGROUND

Acinar cell carcinoma of the pancreas is a rare malignancy representing less than 1% of all pancreatic malignancies.

METHODS

We report on a case series of 21 patients with acinar cell carcinoma of the pancreas treated at a high-volume quaternary center. A systematic review of the medical literature was performed that described typical therapeutic management approaches for acinar cell carcinoma of the pancreas and reported on disease control and survival rates. Data for the case series were obtained from a prospective database.

RESULTS

In our systematic review of 6 articles, study patients had a median age of 61 years, 66% were male, 52% had stage I/II disease, and 55% of lesions were located in the pancreatic head. The rates of median survival were approximately 47 months after resection with adjuvant therapy, 38 months for nonmetastatic, locally unresectable disease, and 17 months for metastatic disease treated with chemotherapy. Combination fluoropyrimidine-based chemotherapy regimens had better rates of disease control than other therapies. Our case series included 21 study patients, 14 of whom required resection and 7 who had metastatic disease. The rates of median survival were 40.2 ± 31.9 months in those who underwent surgery and were treated with adjuvant therapy and 13.8 ± 11.3 months for patients with metastatic disease.

CONCLUSIONS

Multidisciplinary treatment for acinar cell carcinoma of the pancreas should be considered due to the rarity of the disease and its lack of high-level therapeutic data. Progress in the molecular analysis of this tumor may improve outcomes through the use of personalized therapy based on underlying tumor mutations.

A case of multicentric pancreatic mixed acinar-ductal carcinoma diagnosed by a yogurt-like cell clump flowing from the papilla of Vater

BACKGROUND

Histological confirmation is needed when the pancreatic lesions is uncertain for neoplastic or nonneoplastic. Current case with multicentric pancreatic carcinomas showing indefinite clinical images was successfully diagnosed by a biopsy of a novel object expelled from the papilla.

CASE PRESENTATION

A 71-year-old male was referred because of elevated serum pancreatic enzymes. Computed tomography revealed an unclear low-density area in the pancreatic body without evidence of tumor and mild dilation of the upstream main pancreatic duct (MPD). Other images, including abdominal ultrasound, endoscopic ultrasound, and magnetic resonance imaging, did not demonstrate cancerous findings. Endoscopic retrograde cholangiopancreatography showed a crab-claw-like obstruction in the MPD. Surprisingly, the component constituting the obstruction was moved by contrast injection and spilled out of the papilla orifice as a yogurt-like white object. Biopsy of this object by histology revealed a cancer cell clump. Pancreatectomy was performed, and pathology of the resected pancreas showed multiple nodular tumors replacing the acini and extending into the MPD. These neoplasms histologically resembled mixed acinar-ductal carcinoma.

CONCLUSION

Current report presented a rare tumor with multicentric pancreatic lesions, preoperatively diagnosed by a biopsy of an uncommon substance.

Adult pancreatoblastoma - Case report and review of literature

Most cases of pancreatoblastoma, a rare malignant epithelial tumor of the pancreas, are seen in the pediatric population. The rarity of pancreatoblastoma, the similar radiologic findings to those seen in other pancreatic lesions, and its histopathologic heterogeneity, make its preoperative diagnosis in adults a real challenge. We report ultrasound, computed tomography and magnetic resonance imaging correlative findings of a histologically proven pancreatoblastoma in a 37-year-old woman. Pancreatoblastoma should be considered in the differential diagnosis of a pancreatic mass presenting uncommon imaging features.

Sudden disappearance of the blood flow in a case of pancreatic acinar cell carcinoma

A 55-year-old man was referred to our hospital for a further examination of a pancreatic cystic tumor with a solid component exhibiting vascularity. A few days later, the patient was admitted with a complaint of sudden severe epigastric pain. Enhanced CT showed the loss of vascularity in the tumor. In particular, contrast-enhanced endoscopic ultrasonography (EUS) clearly demonstrated the disappearance of the blood flow, and a histological examination revealed acinar cell carcinoma with central necrosis. To our knowledge, this is the first case in the literature of acinar cell carcinoma associated with the sudden disappearance of vascularity. In this case, contrast-enhanced harmonic EUS was especially useful for assessing the degree of vascularity.