Differentiation of prostate cancer and stromal hyperplasia in the transition zone with histogram analysis of the apparent diffusion coefficient

Background Prostate cancer and stromal hyperplasia (SH) in the transition zone (TZ) are difficult to discriminate by conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI). Purpose To investigate the apparent diffusion coefficient (ADC) of prostate cancer and SH in the TZ with histogram analysis and the ability of ADC metrics to differentiate between these two tissues. Material and Methods Thirty-three cancer and 29 SH lesions in the TZ of 54 patients undergoing preoperative DWI (b-value 0, 1000 s/mm²) were analyzed. All the lesions on the MR images were localized based on histopathologic correlations. The 10th, 25th, and 50th percentiles, and the mean ADC values were calculated for the two tissues and compared. The efficiencies of the 10th, 25th, and 50th ADC percentiles in differentiating the two tissues were compared with that of the mean ADC with receiver operating characteristic (ROC) analysis. Results The 10th, 25th, and 50th percentiles and mean ADC values (×10^-3 mm²/s) were 0.86 ± 0.15, 0.89 ± 0.16, 0.94 ± 0.16, and 1.03 ± 0.17 in SH and 0.64 ± 0.12, 0.69 ± 0.12, 0.72 ± 0.16, and 0.83 ± 0.15 in TZ cancer, respectively. The parameters were all significantly lower in cancer than SH. The 10th ADC percentile yielded an area under the ROC curve (AUC) of 0.87 for the differentiation of carcinomas from SH, which was higher than the mean ADC (0.80) ( P < 0.05), and the AUCs of the 25th (0.82) and 50th (0.83) percentiles exhibited no differences from those of the mean ADC ( P > 0.05). Conclusion Histogram analysis of ADC values may potentially improve the differentiation of prostate cancer from SH in the TZ.

Which system is better to predict prognosis of patients with hepatocellular carcinoma treated by transcatheter arterial chemoembolization as initial therapy? Comparison between CLIP and JIS in a Japanese population

Background There has been no consensus as to which system, either the Cancer of the Liver Italian Program (CLIP) or the Japan Integrated Staging (JIS) system, is suitable to predict the prognosis of hepatocellular carcinoma (HCC) patients who underwent transcatheter arterial chemoembolization (TACE) as initial therapy. Purpose To retrospectively compare the usefulness of CLIP and JIS in predicting and stratifying the prognosis of HCC patients treated by TACE. Material and Methods Between 1995 and 2005, consecutive 728 patients with untreated HCC who underwent TACE in our institute were selected for this study. The survival rate and its prognostic factors were assessed by multivariate analysis. Patients were stratified according to the two systems, and their survival rates between the scores were compared. Results The mean follow-up period was 1689 days. The 1-year, 3-year, 5-year, and 10-year survival rates were 83.1%, 55.1%, 34.7%, and 12.8%, respectively. Both systems stratified the prognosis of patients well, but was slightly better in CLIP as compared to in JIS. As for multivariate factor analysis, less severe Child-Pugh classification ( P < 0.001), simple tumor morphology ( P < 0.001), absence of portal vein invasion ( P < 0.001), and lower alpha-fetoprotein (AFP) level ( P < 0.001) were suggested to be independent indicators for favorable survival rate. All of these independent factors were included in CLIP, whereas JIS lacked AFP level. Furthermore, the likelihood χ²-test value was higher, and the Akaike information criterion value was lower for CLIP than for JIS. Conclusion CLIP is more suitable than JIS for predicting prognosis of patients with HCC who would undergo TACE in a Japanese population.

Carcinosarcoma of the uterus: MRI findings including diffusion-weighted imaging and MR spectroscopy

BACKGROUND

Recently carcinosarcoma has become regarded as a subset of endometrial carcinoma. Because the clinical course of carcinosarcoma is aggressive with poor prognosis, it should be differentiated from endometrial carcinomas for the appropriate surgical management and adjuvant therapy.

PURPOSE

To clarify the magnetic resonance imaging (MRI) characteristics of uterine carcinosarcoma including diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurement and MR spectroscopy (MRS) with quantitative metabolite evaluation.

MATERIAL AND METHODS

MRI findings of 12 pathologically diagnosed uterine carcinosarcomas obtained on 3T MRI were retrospectively evaluated. The mean and minimum ADCs, and the lipid and choline concentration levels were compared with those of pathologically diagnosed 38 endometrial carcinomas.

RESULTS

The mean and minimum ADCs in carcinosarcomas and endometrial carcinomas were not significantly different. The mean ADC of carcinosarcomas was significantly higher than that of higher grade (G2 and G3) endometrial carcinomas. The choline concentration in carcinosarcomas was significantly lower than that in endometrial carcinomas. High lipid peak was observed in 91% of carcinosarcomas and in 24% of endometrial carcinomas.

CONCLUSION

Large, exophytic heterogeneous endometrial mass containing strongly enhanced areas, which may exhibit "tumor delivery", is a suggestive of carcinosarcoma. Relatively high mean ADC and low choline concentration considering its highly malignant nature due to intra-tumoral heterogeneity with necrosis and epithelial cystic components, and the presence of necrosis-associated high lipid peak may be compatible with carcinosarcoma.

Value of diffusion-weighted MRI in diagnosis of uterine cervical cancer: a prospective study evaluating the benefits of DWI compared to conventional MR sequences in a 3T environment

BACKGROUND

Imaging of cervical carcinoma remains challenging as local infiltration of surrounding tissues cannot always be discriminated safely. New imaging techniques, like diffusion-weighted imaging (DWI) have emerged, which could lead to a more sensitive tumor detection.

PURPOSE

To evaluate the benefits of DWI for determination of size, local infiltration, and tumor grading, in patients with primary and recurrent cervical cancer.

MATERIAL AND METHODS

In this prospective, study we enrolled 50 patients with primary (n = 35) and recurrent (n = 15) tumors. All patients underwent 3T magnetic resonance imaging (MRI) including conventional (e.g. T1/T2 ± fs ± contrast) sequences and DWI (b-values of 0, 50, 400, 800 s/mm(2)). All images were analyzed by three readers with different experience levels (1, 3, 6 years), who compared image quality, tumor delineation, dimensions, local infiltration, lymph node involvement, and quantified ADC values compared to the histopathological grading.

RESULTS

Additional use of DWI resulted in significantly better (P < 0.001) tumor delineation for the least experienced reader, but not for experienced readers. Tumor dimensions were assessed almost equally (P > 0.05) in conventional sequences and DWI. Use of DWI led to an increase in sensitivity of infiltrated adjacent tissue (from 86% to 90%) and detection of lymph node metastases (from 47% to 67%). Quantitative assessment of carcinomas showed lower ADC values (P < 0.001) with significant inverse correlations between different grading levels.

CONCLUSION

Our study demonstrates the overall benefits using DWI in 3T MRI resulting in a higher reader confidence, sensitivity of tissue infiltration, and tumor-grading for cervical cancer.

Objective measurement of the distal resection margin by MRI of the fresh and fixed specimen after partial mesorectal excision for rectal cancer: 5 cm is not just 5 cm and depends on when measured

BACKGROUND

Most studies have directly established the optimal perioperative in situ clearance margin in surgery for rectal cancer from the histologically observed extent of distal spread, neglecting the tissue variability that occurs after resection and fixation of the rectal specimen.

PURPOSE

To measure the length of the distal resection margin in the fresh and fixed specimen following partial mesorectal excision for rectal cancer using magnetic resonance imaging (MRI) to document tissue shrinkage after surgical removal and fixation.

MATERIAL AND METHODS

The length of the distal resection margin was measured by MRI of the fresh and fixed specimen and at histopathological examination of the fixed specimen in 10 patients who underwent surgery for upper rectal cancer. In addition, tissue shrinkage was estimated by measuring the total length of the fresh and fixed specimen and distance from the peritoneal reflection anteriorly to the distal cut edge of the specimen.

RESULTS

Measured by MRI, the distal resection margin was in the range of 0.6-10.2 cm (mean, 4.6 cm) in the fresh specimen, and 0.5-6.2 cm (mean, 3.2 cm) in the fixed specimen. The tissue shrinkage ratio was a mean of 69% (interquartile range, 61-77%). Taking all ratios from MRI and histopathological examination of tissue shrinkage into account, the collective tissue shrinkage ratio was 70% (95% confidence interval, 67-73%)

CONCLUSION

The length of the distal resection margin was reduced by 30% after surgical removal and fixation of the specimen.

CT triage for lung malignancy: coronal multiplanar reformation versus images in three orthogonal planes

BACKGROUND

Generation of multiplanar reformation (MPR) images has become automatic on most modern computed tomography (CT) scanners, potentially increasing the workload of the reporting radiologists. It is not always clear if this increases diagnostic performance in all clinical tasks.

PURPOSE

To assess detection performance using only coronal multiplanar reformations (MPR) when triaging patients for lung malignancies with CT compared to images in three orthogonal planes, and to evaluate performance comparison of novice and experienced readers.

MATERIAL AND METHODS

Retrospective study of 63 patients with suspicion of lung cancer, scanned on 64-slice multidetector computed tomography (MDCT) with images reconstructed in three planes. Coronal images were presented to four readers, two novice and two experienced. Readers decided whether the patients were suspicious for malignant disease, and indicated their confidence on a five-point scale. Sensitivity and specificity on per-patient basis was calculated with regards to a reference standard of histological diagnosis, and compared with the original report using McNemar's test. Receiver operating characteristic (ROC) curves were plotted to compare the performance of the four readers, using the area under the curve (AUC) as figure of merit.

RESULTS

No statistically significant difference of sensitivity and specificity was found for any of the readers when compared to the original reports. ROC analysis yielded AUCs in the range of 0.92-0.93 for all readers with no significant difference. Inter-rater agreement was substantial (kappa = 0.72).

CONCLUSION

Sensitivity and specificity were comparable to diagnosis using images in three planes. No significant difference was found between experienced and novice readers.

A chondrosarcoma in the anterior mediastinum mimicking a thymoma

A chondrosarcoma in the anterior mediastinum is a rare finding with a relatively good prognosis. We describe a case of a 75-year-old man with a 2-year history of neck discomfort and weight loss. Imaging showed a homogenous tumor with a minor compression on the anterior part of the heart. It had close relation to the ribs, no surrounding fat, and a thymoma was suspected. Biopsy prior to surgery was impossible due to the location of the tumor. Unfortunately, final pathology from the surgical specimen revealed a chondrosarcoma.

Non-infectious cholecystopathy secondary to high-dose IL-2 cancer immunotherapy

Interleukin-2 (IL-2) associated cholecystopathy is a rare manifestation of IL-2 drug toxicity in the setting of cancer immunotherapy. While the imaging data and clinical presentation can easily mimic acute cholecystitis, the correct diagnosis can be made with the particular clinical history, thus avoiding inappropriate surgical management. As more cancer immunotherapies become standard oncologic treatments, specific immunotherapy-associated side effects are also expected to be encountered more frequently in the future and should be recognized as such. We present a case of IL-2-associated cholecystopathy in the setting of renal cell carcinoma immunotherapy.

Invasive cribriform carcinoma of the breast: mammographic, sonographic, MRI, and 18 F-FDG PET-CT features

BACKGROUND

Invasive cribriform carcinoma (ICC) of the breast is a rare type of invasive carcinoma which shows a favorable prognosis and a lower frequency of axillary nodal metastases. Few imaging findings related to ICC have been reported.

PURPOSE

To evaluate imaging findings with multiple imaging techniques in ICC of the breast.

MATERIAL AND METHODS

Twenty-eight cases of histopathologically proven ICC of the breast were gathered for this study. We retrospectively reviewed the mammographic, sonographic, and magnetic resonance imaging (MRI) findings of ICC according to the American College of Radiology (ACR) breast imaging reporting and data system (BI-RADS) lexicon. 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (18 F-FDG PET-CT) findings were also evaluated. Microscopic slides of surgical specimens were reviewed by a breast pathologist.

RESULTS

The mean age of the patients was 51 years. The most common mammographic findings were irregular shape (72.8%), spiculated margin (63.7%), and a high density (81.8%) mass. Microcalcifications were noted in 9/28 cases. The most common shape was pleomorphic (66.7%). The most common sonographic findings were irregular shape (77.8%), spiculated margin (29.6%), hypoechogenicity (81.5%), and no posterior acoustic features (85.2%). On MRI, most ICCs presented as irregular shaped mass (62.0%) and irregular (42.9%) margin. All four patients (16.0%) who presented with non-mass-like enhancement pattern showed a segmental distribution. The 18 F-FDG PET-CT showed a mean maximum standardized uptake value (SUVmax) of 5.90. Axillary nodal metastases were found in 17.9% (5/28) of the surgical specimens. Immunohistochemical studies showed a high positivity for estrogen and progesterone receptor (100% and 87.5%, respectively).

CONCLUSION

The imaging features of invasive cribriform carcinoma are highly suggestive of malignancy and are not distinguishable from those of other breast cancers like infiltrating ductal carcinoma.

Do mammographic tumor features in breast cancer relate to breast density and invasiveness, tumor size, and axillary lymph node involvement?

BACKGROUND

Breast density and mammographic tumor features of breast cancer may carry prognostic information. The potential benefit of using the combined information obtained from breast density, mammographic tumor features, and pathological tumor characteristics has not been extensively studied.

PURPOSE

To investigate how mammographic tumor features relate to breast density and pathological tumor characteristics.

MATERIAL AND METHODS

This retrospective study was carried out within the Malmö Diet and Cancer Study: a population-based cohort study recruiting 17,035 women during 1991-1996. A total of 826 incident breast cancers were identified during follow-up. Mammography images were collected and analyzed according to breast density and tumor features at diagnosis. Pathological data were retrieved from medical reports. Mammographic tumor features in relation to invasiveness, tumor size, and axillary lymph node involvement were analyzed using logistic regression yielding odds ratios (OR) with 95% confidence intervals (CI) and adjusted for age at diagnosis, mode of detection, and breast density.

RESULTS

Tumors presenting as an ill-defined mass or calcifications were more common in dense breasts than tumors presenting as a distinct mass or with spiculated appearance. Invasive cancer was more common in tumors with spiculated appearance than tumors presenting as a distinct mass (adjusted OR, 5.68 [1.81-17.84]). Among invasive tumors, an ill-defined mass was more often large (>20 mm) compared with a distinct mass, (adjusted OR, 3.16 [1.80-5.55]).

CONCLUSION

Tumors presenting as an ill-defined mass or calcifications were more common in dense breasts. Spiculated appearance was related to invasiveness, and ill-defined mass to larger tumor size, regardless of mode of detection and breast density. The potential role of mammographic tumor features in clinical decision-making warrants further investigation.

Transarterial chemoembolization as first-line therapy for hepatocellular carcinomas infeasible for ultrasound-guided radiofrequency ablation: a retrospective cohort study of 116 patients

BACKGROUND

Ultrasound (US)-guided radiofrequency ablation (RFA) is frequently infeasible even for very early or early stage hepatocellular carcinoma (HCC) due to various reasons such as inconspicuous tumors or absence of a safe electrode path and the infeasibility rate is reportedly as high as 45%. In such cases, transarterial chemoembolization (TACE) is a commonly practiced alternative.

PURPOSE

To analyze long-term outcomes including tumor progression patterns and factors contributing to survival of patients who received TACE as the first line of therapy for very early or early stage HCC infeasible for US-guided RFA.

MATERIAL AND METHODS

From October 2006 through October 2009, 116 patients with very early or early stage HCCs underwent the first-line therapy TACE after their tumors were deemed infeasible for RFA. Long-term survival rates were calculated and prognostic factors were assessed by univariate and multivariate analyses. The patterns and rates of tumor progression or recurrence were also evaluated.

RESULTS

The 1, 3, and 5-year survival rates of the whole cohort were 94.7%, 68.4%, and 47.2% with a mean overall survival of 53.1 months (95% CI: 48.2-58.0). Preserved liver function with Child-Pugh class A was the only independent factor associated with longer survival. The most common first tumor progression pattern was intrahepatic distant recurrence. The cumulative rates of local tumor progression and intrahepatic distant recurrence at 1, 3, and 5 years were 33% and 22%, 52% and 49%, and 73% and 75%, respectively.

CONCLUSION

TACE is a viable first-line treatment of HCC infeasible for RFA, especially when liver function was preserved.

Angiomyolipoma with minimal fat and non-clear cell renal cell carcinoma: differentiation on MDCT using classification and regression tree analysis-based algorithm

BACKGROUND

Differentiation between angiomyolipoma with minimal fat (AMLmf) and non-clear cell renal cell carcinoma (nccRCC) may be difficult owing to lack of macroscopic fat in AMLmf. However, the differential points between AMLmf and nccRCC has not been well established in the literature.

PURPOSE

To evaluate quantitative triphasic multidetector computed tomography (MDCT) features that differentiate between small AMLmf and nccRCC, and to integrate them to develop a simple and easy diagnostic algorithm.

MATERIAL AND METHODS

This study was approved by the Institutional Review Board; informed consent was waived. Triphasic MDCT images of pathologically-proven AMLmfs (n = 24) and nccRCCs (n = 55) of 79 patients were retrospectively evaluated. Age, sex, size, long-to-short axis ratio (LSR), attenuation and enhancement degree in all phases, unenhanced tumor-kidney attenuation difference (UTKAD) in Hounsfield units (HU) were compared with Chi-square analysis, independent-samples t-test, and receiver-operating characteristic (ROC) curves. A criterion was formulated with classification and regression tree analysis (CART). Thereafter, CART-based algorithm was tested with additional interpretations from two radiologists. Intra- and inter-observer variability was analyzed with Bland-Altman analysis.

RESULTS

LSR was greater in AMLmf than nccRCC (P < 0.001). AMLmf showed higher attenuation (all phases), CMP enhancement, and wash-out than nccRCC (P ≤ 0.001). UTKAD was greater in AMLmf than nccRCC (P < 0.001). ROC curve analysis yielded area under the curves of 0.936, 0.888, and 0.853 using UTKAD, unenhanced attenuation, and LSR. CART-based algorithm (UTKAD > 7.5 HU, LSR > 1.23) predicted AMLmf with sensitivity, specificity, PPV, and NPV of 87.5%, 96.4%, 91.3%, and 94.6%. Mean intra- and inter-observer difference was -0.1/0.03 HU and -1.0/0.09 HU for UTKAD/LSR, respectively. These interpretations changed the final diagnosis in 1.3% (1/79) and 5.1% (4/79) patients for radiologists 1 and 2.

CONCLUSION

Triphasic MDCT was useful for differentiating AMLmf and nccRCC. CART-based algorithm using UTKAD > 7.5 and LSR > 1.23 was simple and accurate in predicting AMLmf.

Isolated sphenoid fungal sinusitis and coexisting intrasellar mass lesion presenting with headache as the sole symptom

A case of isolated sphenoid fungal sinusitis in an elderly diabetic patient is described. A coexisting mass lesion located in the sellar region was detected incidentally. Coincidence of these two entities represents a potential surgical disaster which may result in direct intracranial spread of fungal infection.

Upper urinary tract tumors: how does the contrast enhancement measured in a split-bolus CTU correlate to histological staging?

BACKGROUND

Computed tomography urography (CTU) is used widely in the work-up of patients with symptoms of urinary tract lesions. Preoperative knowledge of whether a tumor is invasive or non-invasive is important for the choice of surgery. So far there are no studies about the distinction of invasive and non-invasive tumors in ureter and renal pelvis based on the enhancement measured with Hounsfield Units.

PURPOSE

To examine the value of CTU using split-bolus technique to distinguish non-invasive from invasive urothelial carcinomas in the upper urinary tract.

MATERIAL AND METHODS

Patients who underwent nephroureterectomy between 2006 and 2011 and who had split-bolus CTU prior to surgery were included. The images were available electronically. The attenuation values before and after administration of iodine-based contrast media were measured. The radiology, patient, and pathology records were reviewed.

RESULTS

Of the 158 patients who underwent unilateral nephroureterectomy 69 fulfilled the inclusion criteria. Histopathological examination revealed 31 patients with non-invasive and 38 with invasive urothelial carcinoma. Neither absolute attenuation nor change in attenuation values obtained at CTU could distinguish between invasive and non-invasive lesions. No patients had a CTU within the last year before the examination that resulted in surgery.

CONCLUSION

A split-bolus CTU cannot distinguish between invasive and non-invasive urothelial tumors in the upper urinary tract, but the examination is useful to diagnose a tumor in the renal pelvis and the ureter.

Advances in pediatric oncology MRI

Refined stratification of disease is thought to result in better survival from childhood malignant disease while minimizing the adverse effects of anticancer therapies. There is a potential for magnetic resonance imaging (MRI) to contribute to such stratification by improved tissue characterization, anatomical depiction, staging, and assessment of early treatment response. Recent advances in pediatric MRI outside the central nervous system (CNS) are reviewed in this context. The focus is on new applications for conventional MRI and on clinical implementation of tissue-specific and quantitative techniques. This area is largely unexplored, and potential directions for research are indicated.

Predicting local recurrence following breast-conserving treatment: parenchymal signal enhancement ratio (SER) around the tumor on preoperative MRI

BACKGROUND

The level of background parenchymal enhancement around tumor is known to be associated with breast cancer risk. However, there is no study investigating predictive power of parenchymal signal enhancement ratio (SER) around tumor for ipsilateral breast tumor recurrence (IBTR).

PURPOSE

To investigate whether the breast parenchymal SER around the tumor on preoperative dynamic contrast-enhanced magnetic resonance imaging (MRI) is associated with subsequent IBTR in breast cancer patients who had undergone breast-conserving treatment.

MATERIAL AND METHODS

Nineteen consecutive women (mean age, 44 years; range, 34-63 years) with breast cancer who developed IBTR following breast-conserving treatment and 114 control women matched for age, as well as T and N stages were included. We compared the clinicopathologic features of the two groups including nuclear grade, histologic grade, hormonal receptor status, human epidermal growth factor receptor-2 (HER-2) status, lymphovascular invasion, negative margin width, use of adjuvant therapy, and parenchymal SER around the tumor on preoperative DCE-MRI. The SER was measured on a slice showing the largest dimension of the tumor. Multivariate conditional logistic regression analysis was used to identify independent factors associated with IBTR.

RESULTS

In univariate analysis, ER negativity (odds ratio [OR] = 4.7; P = 0.040), PR negativity (OR = 4.0; P = 0.013), HER-2 positivity (OR = 3.6; P = 0.026), and a parenchymal SER greater than 0.53 (OR = 23.3; P = 0.011) were associated with IBTR. In multivariate analysis, ER negativity (OR = 3.8; P = 0.015) and a parenchymal SER greater than 0.53 (OR = 13.2; P = 0.040) on preoperative MRI were independent factors associated with IBTR.

CONCLUSION

In addition to ER negativity, a higher parenchymal SER on preoperative MRI was an independent factor associated with subsequent IBTR in patients with breast cancer who had undergone breast-conserving treatment.

MR features to suggest microinvasive ductal carcinoma of the breast: can it be differentiated from pure DCIS?

BACKGROUND

Morphologic and kinetic characteristics of breast lesions are regarded as a major criterion for their differential diagnosis in dynamic magnetic resonance imaging (MRI). However, there have not been well-reported MRI findings of microinvasive ductal carcinoma.

PURPOSE

To evaluate MRI characteristics of microinvasive ductal carcinoma of the breast and to compare MRI findings in patients with microinvasive ductal carcinoma and pure ductal carcinoma in situ (DCIS).

MATERIAL AND METHODS

Eighty-one patients with pathologically confirmed microinvasive ductal carcinomas (n = 37) or pure DCIS (n = 44) were included in this study. The MRI findings were analyzed without knowledge of the pathologic and conventional imaging findings. For all the lesions detected on MRI, morphologic and kinetic analyses were performed according to the Breast Imaging Reporting and Data System. For the non-mass lesions, the presence of clustered ring enhancement was also analyzed. Statistical analyses were performed using Student's t test, χ(2) test, and Fisher's exact test.

RESULTS

In total 35 cases of microinvasive ductal carcinoma and 39 cases of DCIS were detected on MRI. The most common and dominant MRI findings of microinvasive ductal carcinoma and DCIS were non-mass lesions with heterogeneous enhancement. However, the spiculated margin of the mass-type lesion (P = 0.022), the segmental distribution (P = 0.023), and clustered ring enhancement (P = 0.006) of the non-mass-type lesion, and the enhancement kinetics showing strong initial enhancement (P = 0.004) with subsequent wash-out (P = 0.001) were significantly more frequent in microinvasive ductal carcinoma than in DCIS.

CONCLUSION

Non-mass lesions with segmental distribution, heterogeneous enhancement, and strong initial enhancement with a wash-out curve were the dominant MRI findings of microinvasive ductal carcinoma. Compared with DCIS, microinvasive ductal carcinoma showed more suspicious imaging characteristics. For the non-mass lesions, clustered ring enhancement was also a characteristic finding of microinvasion on MRI.

Primary hepatic neuroendocrine tumor: gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging

We present a case of a 71-year-old man with prostate cancer who had no prior underlying liver disease. During metastatic evaluation, a solid mass in the liver was identified by computed tomography and ultrasound. Gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging demonstrated a well-defined, peripheral enhancing hepatic mass containing small cystic component. This lesion was diagnosed as hepatic neuroendocrine tumor. Primary neuroendocrine tumors of the liver are extremely rare. This case is interesting because of the rarity of this neoplasm and the unique radiologic findings despite its small size. Reviews of previously reported cases in the literature are also presented.

Primary signet ring cell carcinoma of the appendix mimicking acute appendicitis

Primary signet ring cell carcinoma of the appendix is a very rare neoplasm that usually presents with signs and symptoms of acute appendicitis and in particular with a right lower abdominal pain. Preoperative imaging detection of appendiceal adenocarcinoma has an important value because it may result in an appropriate surgical procedure. We report a rare case of primary signet ring cell carcinoma of the vermiform appendix in an 80-year-old man who was misdiagnosed on computed tomography (CT) scan as acute appendicitis.

Urachal carcinoma: imaging findings

Urachal carcinoma is a rare neoplasm, which accounts for only 0.5-2% of bladder malignancies, and arises from a remnant of the fetal genitourinary tract. A 46-year-old woman presented with a history of pelvic pain and frequent daytime urination. Ultrasound (US), computed tomography (CT), and magnetic resonance (MR) demonstrated a supravesical heterogeneous mass with calcifications. The patient underwent a partial cystectomy with en-bloc resection of the mass and histopathological examination revealed the diagnosis of urachal adenocarcinoma. Urachal carcinomas are usually associated with poor prognosis and early diagnosis is fundamental. CT and MR are useful to correctly diagnose and preoperatively staging.