Clinical and histopathological parameters in transrectal ultrasound-guided biopsies associated with tumor upgrading after radical prostatectomy: A comparative analysis of risk groups.

BACKGROUND: Thanks to technological advances, prostate cancer (PCa) can be diagnosed at a younger age. It is known that most of these patients are in the low-intermediate risk group, and the histological grade of the tumor increases in half of those undergoing radical prostatectomy (Rp) compared to their diagnostic biopsies. This is especially important in terms of active surveillance (AS) and/or the timely evaluation of curative treatment options in patients diagnosed at an early age. Our aim was to investigate clinical and histopathological parameters that may be associated with an increase in the histological grade of the tumor in patients with acinar adenocarcinoma who were diagnosed by transrectal ultrasound-guided biopsy (TRUS-Bx) and underwent Rp. METHODS: A total of 205 patients with classical acinar adenocarcinoma diagnosed by TRUS-Bx without metastasis and who underwent Rp were grouped according to the D'Amico risk classification. Age at diagnosis, serum prostate-specific antigen (PSA), PSA density, prostate volume, Prostate Imaging Reporting and Data System (PI-RADS) score, clinical stage, Gleason Grade Group (GGG), high-grade intraepithelial neoplasia in tumor-free cores (HGPIN) (single and ≥2 cores), perineural invasion (PNI), and lymphovascular invasion (LVI) was obtained. Additionally, GGG, pathological stage, lymph node metastasis, surgical margin positivity, and tumor volume obtained from Rp were evaluated. Comparisons were made between the case groups in which the tumor grade increased and remained the same, in terms of age, serum PSA, PSA density, HGPIN in tumor-free cores (single and ≥2 cores), PNI, and LVI in all biopsies (with or without tumors), as well as risk groups. In addition, the relationships of HGPIN in tumor-free cores (single and ≥2 cores), PNI, and LVI on TRUS-Bx with age, serum PSA and PSA density, tumor volume, surgical margin positivity, pathological stage, lymph node metastasis, and risk groups were examined separately. RESULTS: Of the patients, 72 (35.1%) were in the low-risk group, 95 (46.3%) in the intermediate-risk group, and 38 (18.5%) in the high-risk group. Most of the patients with an increased histological grade (n = 38, 48.1%) were in the low-risk group (p < 0.05) and had an advanced median age. HGPIN in single and ≥2 tumor-free cores and PNI were more common in these patients (p < 0.01, p < 0.001, and p < 0.05, respectively). According to the multivariable analysis, advanced age (odds ratio [OR]: 1.087, 95% confidence interval [CI]: 1.029-1.148, p < 0.05), high serum PSA (OR: 1.047, 95% CI: 1.006-1.090, p < 0.05), HGPIN in ≥2 tumor-free cores (OR: 6.346, 95% CI: 3.136-12.912, p < 0.001), and PNI (OR: 3.138, 95% CI: 1.179-8.356, p < 0.05) were independent risk factors for a tumor upgrade. Furthermore, being in the low-risk group was an independent risk factor when compared to the intermediate- and high-risk groups (OR: 0.187, 95% CI: 0.080-0.437, p < 0.001 and OR: 0.054, 95% CI: 0.013-0.230, p < 0.001, respectively). The HGPIN diagnosis was more common in the low- and intermediate-risk groups. Advanced age at diagnosis, high serum PSA and PSA density values were associated with PNI on TRUS-Bx. High serum PSA and PSA density values were associated with LVI on TRUS-Bx. Surgical margin positivity was higher in cases with PNI and LVI detected by TRUS-Bx. HGPIN in ≥2 tumor-free cores, PNI, and LVI on TRUS-Bx were associated with a higher rate of lymph node metastases. CONCLUSIONS: In patients diagnosed with acinar adenocarcinoma, the presence of HGPIN even in a single tumor-free core on TRUS-Bx was found to be significant in terms of showing an increase in the histological tumor grade in Rp. The diagnosis of HGPIN in ≥2 tumor-free cores on TRUS-Bx was determined as an independent risk factor for an increased Gleason score after Rp. Furthermore, an advanced age, a high serum PSA value, being in the low-risk group, and the presence of PNI were associated with a tumor upgrade. HGPIN in ≥2 tumor-free cores, PNI, and LVI were also associated with lymph node metastasis. Therefore, the diagnosis of HGPIN should be signed out on pathological reports.

Nomogram Models for Distinguishing Intraductal Carcinoma of the Prostate From Prostatic Acinar Adenocarcinoma Based on Multiparametric Magnetic Resonance Imaging.

OBJECTIVE: To compare multiparametric magnetic resonance imaging (MRI) features of intraductal carcinoma of the prostate (IDC-P) with those of prostatic acinar adenocarcinoma (PAC) and develop prediction models to distinguish IDC-P from PAC and IDC-P with a high proportion (IDC ≥ 10%, hpIDC-P) from IDC-P with a low proportion (IDC < 10%, lpIDC-P) and PAC. MATERIALS AND METHODS: One hundred and six patients with hpIDC-P, 105 with lpIDC-P and 168 with PAC, who underwent pretreatment multiparametric MRI between January 2015 and December 2020 were included in this study. Imaging parameters, including invasiveness and metastasis, were evaluated and compared between the PAC and IDC-P groups as well as between the hpIDC-P and lpIDC-P subgroups. Nomograms for distinguishing IDC-P from PAC, and hpIDC-P from lpIDC-P and PAC, were made using multivariable logistic regression analysis. The discrimination performance of the models was assessed using the receiver operating characteristic area under the curve (ROC-AUC) in the sample, where the models were derived from without an independent validation sample. RESULTS: The tumor diameter was larger and invasive and metastatic features were more common in the IDC-P than in the PAC group (P < 0.001). The distribution of extraprostatic extension (EPE) and pelvic lymphadenopathy was even greater, and the apparent diffusion coefficient (ADC) ratio was lower in the hpIDC-P than in the lpIDC-P group (P < 0.05). The ROC-AUCs of the stepwise models based solely on imaging features for distinguishing IDC-P from PAC and hpIDC-P from lpIDC-P and PAC were 0.797 (95% confidence interval, 0.750-0.843) and 0.777 (0.727-0.827), respectively. CONCLUSION: IDC-P was more likely to be larger, more invasive, and more metastatic, with obviously restricted diffusion. EPE, pelvic lymphadenopathy, and a lower ADC ratio were more likely to occur in hpIDC-P, and were also the most useful variables in both nomograms for predicting IDC-P and hpIDC-P.

A case of unresectable ectopic acinar cell carcinoma developed in the portal vein in complete response to FOLFIRINOX therapy.

A 56-year-old man presented to our hospital for close examination of a mass in the portal vein. CT showed a homogeneously enhanced mass occupying the portal vein. No other lesions suggestive of a primary tumor were detected. Endoscopic ultrasound-guided fine-needle aspiration revealed that the tumor was pathologically acinar cell carcinoma (ACC) based on the positive staining for both BCL-10 and trypsin. He was diagnosed with an ectopic ACC developed in the portal vein. Because the tumor invaded secondary branches of the right intrahepatic portal vein and the superior mesenteric vein, it was considered surgically un-resectable. Therefore, chemotherapy with gemcitabine plus nab-paclitaxel (GEM + nab-PTX) was started. After 2 courses, CT showed progressive disease, so the regimen was switched to FOLFIRINOX. After starting treatment with FOLFIRINOX, the tumor shrank gradually. After 29 courses, CT scan eventually showed disappearance of the tumor and complete response was achieved. After 34 courses, the chemotherapy was discontinued. Since then, the patient has been recurrence-free for 5 years. Our English literature review yielded 6 cases, including this case, of un-resectable ACC in which complete response was achieved by chemotherapy. Our case suggest that platinum-based regimen might be an effective therapy for un-resectable ACC, including ectopic ACC.

[MRI findings of parotid acinic cell carcinoma in 19 consecutive cases].

PURPOSE: To describe the MRI features of acinar cell carcinoma of parotid gland (AciCC) and to evaluate the diagnostic value of MR functional imaging. METHODS: A total of 269 cases of maxillofacial AciCC confirmed by surgery and pathology were analyzed. Among them, nineteen subjects with AciCC in the parotid gland underwent preoperative MRI examination (non-enhanced scan for one case, enhanced scan for 18 cases), seventeen patients underwent diffusion-weighted imaging scan, and 15 patients underwent dynamic contrast-enhanced scan. MRI findings of 19 patients were retrospectively analyzed. The lesion size, location, morphology, margin, internal composition, enhancement pattern and functional imaging characteristics were analyzed. SPSS 25.0 software package was used for statistical analysis. RESULTS: Among 269 cases of maxillofacial AciCC, there were 108 males and 161 females, male: female = 1:1.49, aged from 4 to 89 years, with a mean age of (45.95±17.33) years. 84.4% (227/269) were located in the parotid gland. On MRI images, 78.9% (15/19) had well-defined margin, 57.9% (11/19) were round or oval, and 36.8% (7/19) were lobed nodules. One case had irregular morphology and peripheral invasion. The range of maximum diameter was 6-56 mm, averaging (24.8±15.3) mm. Internal composition showed 57.9% (11/19) were cystic solid, 42.1% (8/19) were solid, 31.6% (6/19) had bleeding. T2-weighted MRI showed 52.6% (10/19) with envelope structure, 15.8% (3/19) with low signal separation inside, 38.9%(7/18) had uniform enhancement, and 61.1%(11/18) had uneven enhancement. Functional imaging showed the mean ADC value of tumor was (1.026±0.194)×10-3 mm2/s(n=17). 86.7%(13/15) TIC was type Ⅱ. CONCLUSIONS: Most maxillofacial AciCC are located in the parotid gland. It is difficult to distinguish AciCC from benign tumors with conventional MRI in morphology. The ADC value of AciCC is lower than that of benign tumors, and the type of TIC curve is mostly type Ⅱ. Combination of morphology and functional imaging can improve the diagnostic accuracy of this disease.

Pancreatic Acinar Cell Carcinoma Presenting with Diffuse Pancreatic Enlargement.

Pancreatic acinar cell carcinoma (PACC) is a rare tumor of the exocrine pancreas. It accounts for only 1% of all pancreatic malignancies. A 39-year woman sought treatment for repeated abdominal pain and jaundice. The computed tomography (CT) and magnetic resonance imaging (MRI) suggested diffuse enlargement of the pancreas. 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT showed diffuse enlargement of the pancreas and increased glucose uptake. The endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy of the pancreas was performed, and the case was finally diagnosed as PACC. After the sixth course of chemotherapy with gemcitabine and albumin paclitaxel, a CT scan showed significant shrinkage of the pancreas. PACC very rarely presents with diffuse enlargement of the pancreas. This case illustrates a rare presentation of PACC with diffuse pancreatic enlargement, which was effectively treated with gemcitabine and albumin paclitaxel chemotherapy. Key Words: Pancreatic acinar cell carcinoma, Positron emission tomography/computed tomography, Chemotherapy.

Imaging identification of primary mammary analogue secretory carcinoma and acinic cell carcinoma in major salivary glands.

OBJECTIVE: The present study aimed to characterize and differentiate the ultrasonography (US) and computed tomography (CT) features of mammary analogue secretory carcinoma (MASC) and acinic cell carcinoma (AciCC). METHODS AND PATIENTS: A total of 83 patients with clinically proven MASC and AciCC were analyzed. The following characteristics were assessed on US, CT, and magnetic resonance imaging: lesion size, shape, margin, echogenicity, echotexture, cystic components, posterior echo, vascularity, density, degree of enhancement, enhancement pattern, signal intensity (SI) on T1- and T2-weighted images (WI), hemorrhages, and lymph node enlargement. RESULTS: Similarities were observed between the imaging performance of MASC and AciCC. Differences between the two characteristics of shape on US and cystic components on CT were statistically significant. The proportion of MASC to regular shape on US (p = 0.006) and cystic components on CT (p = 0.027) was significantly higher than that of AciCC. Regular shape on US had the highest sensitivity in the identification of MASC and AciCC, while regular shape on US + cystic component on CT had the highest specificity. CONCLUSIONS: The shape on US and cystic components on CT are key characteristics for distinguishing MASC and AciCC.

68Ga-DOTATATE PET/CT Uptake in Prostate With an Incidental Finding of Prostatic Acinar Adenocarcinoma and Metastatic Neuroendocrine Cancer to the Liver.

ABSTRACT: A 69-year-old man with history of metastatic neuroendocrine tumor presented for initial staging with 68Ga-DOTATE PET/CT. 68Ga-DOTATATE PET/CT showed incidental focal increased DOTATATE uptake in the left apical prostate tissue, which was thought to be of benign etiology. Digital rectal examination later was consistent with a palpable nodule along with elevated prostate-specific antigen of 7.0 ng/mL. MRI of prostate demonstrated a 3.8-cm lesion followed by a targeted biopsy that revealed prostatic acinar adenocarcinoma. Chronic inflammatory cell infiltrates were also noted on biopsy, and this may have been the cause of increased DOTATATE uptake seen on 68Ga-DOTATATE PET/CT study.

Acinar Cell Carcinoma with Morphological Change in One Month.

A 64-year-old man was admitted to our hospital to undergo examination of a pancreatic tumor accompanied by sudden epigastric pain. The tumor had a well-defined oval shape that was mostly less enhanced, with the exception of part of the tumor on the pancreatic head side, on contrast enhanced (CE)-CT. However, CE-CT performed one-month later revealed that the viable part of the tumor grew toward the pancreatic tail with the reduction of necrotic tissue. We performed distal pancreatectomy and the tumor was diagnosed as acinar cell carcinoma (ACC). One important characteristic of ACC is that it may develop morphological changes within a short period of time.

Differential diagnosis between acinic cell carcinoma and pleomorphic adenoma using the quantitative parameters of contrast-enhanced ultrasound.

OBJECTIVE: To investigate the value of differential diagnosis between acinic cell carcinoma (ACC) and pleomorphic adenoma (PA) using the quantitative parameters of contrast-enhanced ultrasound (CEUS). PATIENTS AND METHODS: Twenty-two ACC and 98 PA were retrospectively analyzed. These patients had been examined via routine pre-surgical two-dimensional ultrasound and CEUS. The examination results were confirmed by biopsy pathology. Qontrast 4.0 imaging analysis software was applied to obtain the maximum intensity (PEAK), time to peak (TTP), regional blood volume (RBV), regional blood flow (RBF), maximum signal intensity (SImax) and mean signal intensity (SImean) through quantitative analysis. The differences between ACC and PA were compared regarding the conventional ultrasound images and the quantitative parameters of CEUS. ROC curves were drawn to evaluate the diagnostic value of these parameters. RESULTS: There were no statistically significant differences between salivary gland ACC and PA in the manifestations of conventional two-dimensional ultrasound examination regarding morphology, internal echo and the boundary (p > 0.05). However, there were significant differences in PEAK, RBV, RBF, SImax and SImean between ACC and PA (p < 0.05). Additionally, the five quantitative parameters of CEUS were all highly accurate diagnostic indicators. The maximum area under the curve of each parameter was 0.888, sensitivity 72.6%, specificity 90.9% and accuracy 81.8%. CONCLUSIONS: The quantitative parameters of CEUS are helpful for differentially diagnosing salivary ACC and PA.

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

BACKGROUND: The majority of gastrointestinal tumors are adenocarcinomas. Rarely, there are other types of tumors, such as acinar cell carcinoma, and these are often called pancreatic-type acinar cell carcinomas. Among these tumors, some are differentiated into neuroendocrine components. A few of them are MiNENs. CASE PRESENTATION: The patient was an 80-year-old male who was referred to our hospital for treatment of a pedunculated gastric tumor. It was 5 cm in diameter and detected in the upper gastric body with upper GI endoscopy conducted to investigate anemia. In the biopsy, although hyperplasia of gastric gland cells was noted, no tumor cells were found. Retrospectively, the diagnosis was misdiagnosed. An operation was arranged because bleeding from the tumor was suspected as a cause of anemia and because surgical resection was considered to be desirable for accurate diagnosis. Hence, laparoscopic and endoscopic cooperative surgery was performed. In the pathological examination, several types of epithelial cells that proliferated in the area between the mucosa and deep inside the submucosa were observed. These consisted of acinar-glandular/trabecular patterns and solid. A diagnosis of pancreatic-type acinar cell carcinoma of the stomach with NET G2 and G3 was made based on characteristic cellular findings and the results of immunostaining tests. Each of them consisted of more than 30% of the lesion; a diagnosis of pancreatic-type mixed acinar neuroendocrine carcinoma (pancreatic-type MiNEN) of the stomach or a type of gastric MiNEN was obtained. Anemia was resolved after the operation, and the patient was discharged from the hospital without perioperative complications. CONCLUSIONS: Pancreatic-type ACC of the stomach that is differentiated into neuroendocrine tumors is very rare. Hence, we report this case along with a literature review.

Intravoxel Incoherent Motion Magnetic Resonance Imaging for Assessing Parotid Gland Tumors: Correlation and Comparison with Arterial Spin Labeling Imaging.

OBJECTIVE: To compare and correlate the findings of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging and arterial spin labeling (ASL) imaging in characterizing parotid gland tumors. MATERIALS AND METHODS: We retrospectively reviewed 56 patients with parotid gland tumors evaluated by MR imaging. The true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and fraction of perfusion (f) values of IVIM imaging and tumor-to-parotid gland signal intensity ratio (SIR) on ASL imaging were calculated. Spearman rank correlation coefficient, chi-squared, Mann-Whitney U, and Kruskal-Wallis tests with the post-hoc Dunn-Bonferroni method and receiver operating characteristic curve assessments were used for statistical analysis. RESULTS: Malignant parotid gland tumors showed significantly lower D than benign tumors (p = 0.019). Within subgroup analyses, pleomorphic adenomas (PAs) showed significantly higher D than malignant tumors (MTs) and Warthin's tumors (WTs) (p < 0.001). The D* of WTs was significantly higher than that of PAs (p = 0.031). The f and SIR on ASL imaging of WTs were significantly higher than those of MTs and PAs (p < 0.05). Significantly positive correlation was found between SIR on ASL imaging and f (r = 0.446, p = 0.001). In comparison with f, SIR on ASL imaging showed a higher area under curve (0.853 vs. 0.891) in discriminating MTs from WTs, although the difference was not significant (p = 0.720). CONCLUSION: IVIM and ASL imaging could help differentiate parotid gland tumors. SIR on ASL imaging showed a significantly positive correlation with f. ASL imaging might hold potential to improve the ability to discriminate MTs from WTs.

Non-Ductal Tumors of the Pancreas.

Non-ductal tumors of the pancreas are relatively rare tumors and include pancreatic neuroendocrine tumors (PanNETs), poorly differentiated neuroendocrine carcinomas, acinar cell carcinoma, solid pseudopapillary neoplasm, and pancreatoblastoma. These tumors have a morphology and biology that is distinct from that of ductal neoplasms of the pancreas. PanNETs are the most common tumors among this group. A brief summary of each tumor is described here with an emphasis on the clinical presentation, cytological features, tumor histology, and immunohistochemical profile. Differential diagnoses for each entity are also discussed.

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.

[Acinic cell carcinoma: an unsuspected malignancy of the nasal cavity]. / Une présentation inhabituelle d'un carcinome à cellules acineuses.

Acinic cell carcinoma (ACC) is a low grade malignant tumor of the salivary glands. Primary ACC affects most frequently the parotid gland and can rarely arise in the minor salivary glands of the oral cavity, pharynx and larynx. It is extremely rare in the nasal cavity; to our knowledge only 18 cases of primary ACC of the nasal cavity are reported in the English-written literature. Herein we report a case of acinic cell carcinoma of the nasal cavity, describe the clinical, radiological and microscopic features of this uncommon presentation and finally provide a discussion in the light of relevant literature.

A rare case of pulmonary typical carcinoid with prominent acinic cell differentiation, resembling acinic cell carcinoma.

We herein describe a rare case of low-grade endobronchial tumor that exhibited two distinct features of typical carcinoid and acinic cell carcinoma (ACC) by immunohistochemical and ultrastructure study. ACC was suspected on transbronchial biopsy. The resected specimen showed that the tumor surface comprised an acinic cell component (40% of the tumor), and the central area comprised typical carcinoid (60% of the tumor). The acinic cell component was positive for chromogranin A, synaptophysin and alpha-1-antichymotrypsin. Additionally, this component showed focal apical membranous staining for DOG1 and weak positivity for BCL10 and SOX10. Conversely, the carcinoid component was negative for all proteins except for chromogranin A and synaptophysin. Electron microscopy indicated zymogen-type granules (600-800 nm in diameter) in the acinic cell component, whereas neuroendocrine-type granules (200-300 nm in diameter) were observed in the carcinoid component. Nuclear NR4A3 immunostaining, which is highly specific for ACC of the salivary gland, was negative in this case. We conclude that the pulmonary carcinoid tumor with true zymogen-type granules could be seen but showed superficial similarities to ACC based on negative nuclear staining for NR4A3. Pulmonary carcinoids encompass a wide morphological spectrum and may exhibit prominent acinic cell differentiation.

Pancreatic Ductal Adenocarcinoma in Remnant Pancreas after Pancreaticoduodenectomy for Acinar Cell Carcinoma: A Case Report.

We report a case of a pancreatic ductal adenocarcinoma (PDAC) in the remnant pancreas of a 78-year-old man after pancreaticoduodenectomy for acinar cell carcinoma, a relatively rare pancreatic neoplasm. After diagnosis of pancreatic carcinoma, subtotal stomach-preserving pancreaticoduodenectomy was performed. The pathological diagnosis was acinar cell carcinoma of the pancreas (disease stage IA, pT1, pN0, M0), without regional lymph node invasion. Cancer antigen 19-9 levels gradually increased during the 22 months after surgery, and computed tomography showed two solid tumors, 1.1 and 2.1 cm in diameter, at the site of the remnant pancreas. Endoscopic ultrasound fine-needle aspiration revealed pancreatic ductal adenocarcinoma. The tumor cells were not immunoreactive for trypsin. Both tumors were diagnosed as PDAC of the remnant pancreas. The patient declined curative resection, and chemoradiotherapy was started as alternative treatment. The patient died 28 months after surgery. Because this is an extremely rare case, additional cases and studies are needed in order to clarify its pathogenesis.

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.

Metastatic Acinic Cell Carcinoma to the Vagina: A First Reported Case.

This is a case of a 62-year-old woman with a remote history of acinic cell carcinoma of the parotid gland, who presented with a palpable vaginal mass, anterior vaginal wall prolapse, and stress urinary incontinence. A 2 cm firm mobile mass on the anterior vaginal wall was found on clinical examination. A computed tomographic scan revealed a mass between the vaginal vault and bladder that was eventually surgically excised. The histology, supported by the immunohistochemistry, revealed metastatic acinic cell carcinoma to the vagina after 37 years of her initial diagnosis. This is the first reported case in the literature to occur in the vagina.

[Visually Isoattenuating Pancreatic Acinar Cell Carcinoma:Report of One Case].

Acinar cell carcinoma of pancreas(ACCP)is a rare pancreatic exocrine tumor that accounts for about 1% of pancreatic tumors. The typical imaging manifestations of ACCP are as follows:(1)the tumor is large in volume,partially or completely exophytic;(2)complete or incomplete capsule is visible with thin linear enhancement;(3)CT density and MRI signal:plain CT images reveals that the tumors have similar or slightly hypodense densities relative to the adjacent normal pancreas,the solid part of ACCP has low to intermediate signal intensity on T1WI and intermediate to high signal intensity on T2WI compared with the surrounding normal pancreas;(4)pattern of enhancement:tumors exhibit heterogeneous enhancement and it is less than that in the surrounding normal pancreas;(5)fissure-like,swirling necrosis that may be a characteristic change of tumor;(6)pancreatic and biliary duct dilatation is rare;(7)adjacent organs and blood vessels around the pancreas may be invaded;(8)distant metastasis of liver and other parts may be observed;(9)PET-CT shows high FDG uptake. An ACCP patient with atypical imaging manifestations was treated in Peking Union Medical College Hospital from November 2015 to August 2017. The lesion manifested iso-enhancement and many imaging examinations failed to find the tumor. The patient ultimately underwent surgery and diagnosed as ACCP by pathology.