A review on the added value of whole-body MRI in metastatic lobular breast cancer.

Invasive lobular breast carcinomas (ILC) account for approximately 15% of breast cancer diagnoses. They can be difficult to diagnose both clinically and radiologically, due to their infiltrative growth pattern. The pattern of metastasis of ILC is unusual, with spread to the serosal surfaces (pleura and peritoneum), retroperitoneum and gastrointestinal (GI)/genitourinary (GU) tracts and a higher rate of leptomeningeal spread than IDC. Routine staging and response assessment with computed tomography (CT) can be undertaken quickly and measurements can be reproduced easily, but this is challenging with metastatic ILC as bone-only/bone-predominant patterns are frequently seen and assessment of the disease status is limited in these scenarios. Functional imaging such as whole-body MRI (WBMRI) allows the assessment of bone and soft tissue disease by providing functional information related to differences in cellular density between malignant and benign tissues. A number of recent studies have shown that WBMRI can detect additional sites of disease in metastatic breast cancer (MBC), resulting in a change in systemic anti-cancer therapy. Although WBMRI and fluorodeoxyglucose-positron-emission tomography-computed tomography (FDG-PET/CT) have a comparable performance in the assessment of MBC, WBMRI can be particularly valuable as a proportion of ILC are non-FDG-avid, resulting in the underestimation of the disease extent. In this review, we explore the added value of WBMRI in the evaluation of metastatic ILC and compare it with other imaging modalities such as CT and FDG-PET/CT. We also discuss the spectrum of WBMRI findings of the different metastatic sites of ILC with CT and FDG-PET/CT correlation. KEY POINTS: • ILC has an unusual pattern of spread compared to IDC, with metastases to the peritoneum, retroperitoneum and GI and GU tracts, but the bones and liver are the commonest sites. • WBMRI allows functional assessment of metastatic disease, particularly in bone-only and bone-predominant metastatic cancers such as ILC where evaluation with CT can be challenging and limited. • WBMRI can detect more sites of disease compared with CT, can reveal disease progression earlier and provides the opportunity to change ineffective systemic treatment sooner.

Radiologic features of breast cancer after mantle radiation therapy for Hodgkin disease: a study of 230 cases.

PURPOSE: To retrospectively review diagnostic mammography in women diagnosed with breast cancer who previously had mantle field radiation therapy for Hodgkin disease in England and Wales over a period of 30 years. MATERIALS AND METHODS: From a national cohort study of 5002 women treated with supradiaphragmatic radiation therapy when they were younger than 36 years (mean, 22.1 years) during 1956-2003, 392 patients developed breast cancer. With ethics committee approval and informed consent, mammograms were obtained that showed 230 tumors in 222 (56.6%) patients from 95 hospitals, and the size and appearance of each carcinoma was recorded by two breast radiologists. Comparison was made with a historical report of more than 1000 general-population breast cancers by using Pearson χ(2) test. RESULTS: Thirty-eight tumors were occult on mammograms. Mean tumor maximum diameter was 12.3 mm (n = 81) on oblique view. The quadrant distribution of the tumors was significantly different (P < .001) from the historic controls, and chest radiation therapy patients had a greater proportion of tumors in the upper outer (66.9% [107 of 160] vs 48.7% [385 of 784]) and, to a lesser extent, lower inner (10.6% [17 of 160] vs 7.8% [61 of 784]) quadrants. The dominant radiologic feature was of an irregular mass (56.8% [109 of 192]) followed by microcalcifications (25.0% [48 of 192]). CONCLUSION: This study suggests that in patients who previously underwent mantle radiation therapy for Hodgkin disease, breast cancers are more commonly seen within the upper outer quadrants than are cancers in the general population. Poorly defined masses were the most common appearance.

Diffusion-weighted imaging of the high-risk breast: Apparent diffusion coefficient values and their relationship to breast density.

PURPOSE: To document the apparent diffusion coefficient (ADC) of fibroglandular breast tissue in women at high-risk of developing breast cancer and investigate the relationship between ADC and breast density. MATERIALS AND METHODS: Local research ethics approval was obtained. A total of 33 high-risk women including 17 BRCA1/2 mutation carriers (mean age, 43 years) and 16 women postmantle irradiation (mean age 40 years) underwent diffusion-weighted MRI between days 6 and 16 of their menstrual cycle. ADC histograms from a region of interest in fibroglandular tissue and mammographic breast density measurements were obtained. Mean, percentile ADC values (10th, 25th, 50th, 75th, 90th) and skew were compared for the two groups; ADC and mammographic breast density were correlated. RESULTS: Mean ADC values (×10(-6) mm(2) /s) were 2017 ± 197 in postmantle irradiated women and 1827 ± 289 in BRCA1/2 mutation carriers (P = 0.035) with significant differences at all percentiles (P < 0.0001) but not skew (P = 0.44). ADC values showed weak positive correlation with mammographic breast density in BRCA1/2 mutation carriers (r = 0.51, P = 0.043) but not in postmantle radiotherapy patients (r = 0.49, P = 0.13). CONCLUSION: Higher ADC values seen in fibroglandular tissue postmantle irradiation compared with BRCA1/2 mutation carriers has potential to improve tumor detection in these patients. Lack of correlation between ADC and breast density postmantle irradiation may be a result of microstructural changes.

The breast lesion excision system (BLES): a novel technique in the diagnostic and therapeutic management of small indeterminate breast lesions?

OBJECTIVE: To investigate whether the breast lesion excision system (BLES) could render formal surgery unnecessary in patients with small indeterminate breast lesions. METHODS: Following review board ethical permission and the consent of each patient, we aimed to perform a complete excision biopsy, with a margin, of small indeterminate breast lesions that measure less than 1 cm. 76 patients with small BIRADS type 3 breast lesions underwent a BLES biopsy. Mean radiological lesion size was 7.1 mm (range 2-10 mm). RESULTS: 61 lesions had a final benign diagnosis, 6 of which underwent subsequent surgery although only 1 showing residual lesion. 15 lesions were malignant but with residual tumour at re-excision present in only 5 cases. CONCLUSION: The BLES biopsy is an efficacious technique at excising small indeterminate breast lesions with a complete margin without the need for follow-up diagnostic surgery in the majority.

Adult rhabdomyosarcoma: cross-sectional imaging findings including histopathologic correlation.

OBJECTIVE: The purpose of our study was to present the MRI and CT features of adult rhabdomyosarcomas with histopathologic correlation. Forty-nine sequential cases were incorporated over a 5-year period from the sarcoma unit database. Twenty-six patients had adequate imaging (16 MRI, 10 CT) and histopathology available for retrospective review. The alveolar subtype was present in 13 patients, embryonal subtype in four patients, and pleomorphic subtype in nine patients. On both CT and T1-weighted MRI, all tumors were isodense to skeletal muscle, although enhancement was variable after the administration of IV contrast material. Pleomorphic tumors were very high signal on T2-weighted/STIR imaging, and both pleomorphic and alveolar subtypes were extremely heterogeneous. Embryonal tumors were more homogeneous. CONCLUSION: Although adult rhabdomyosarcomas have certain imaging appearances in common with other soft-tissue sarcomas, features at presentation such as tumor heterogeneity, site, regional lymphadenopathy, and pulmonary metastasis should make the radiologist consider this important diagnosis.

Rectal carcinoma: MRI with histologic correlation before and after chemoradiation therapy.

OBJECTIVE: The purpose of this study was to use MRI to compare the morphologic features of rectal cancer before and 6 weeks after chemotherapy and radiation treatment to correlate the posttreatment MRI appearances with the histologic findings in resected tumors. MATERIALS AND METHODS: High-resolution T2-weighted MRI was performed before and immediately after a standardized 5-week course of chemoradiation therapy in the care of 30 patients with locally advanced adenocarcinoma of the rectum. Changes in morphologic features were evaluated with respect to primary tumor and nodal downstaging. The MRI findings after chemoradiation therapy were compared with the histologic findings in the resected specimens with respect to prediction of tumor stage and showing the relation between the tumor and the circumferential margin of resection. RESULTS: Tumor shrinkage > 30% was found in 19 (63%; 95% CI, 46-81%) of 30 patients, but changes in MRI T stage occurred in only five (17%; 95% CI, 3-30%) of 30 patients. Tumor regression from the circumferential resection margin was found in five patients, all findings confirmed at histologic examination. Nodal downstaging was observed in 13 (68%; 95% CI, 48-89%) of 19 patients; 11 patients were node free on the basis of both MRI findings and subsequent histologic results. Overall prediction of distance between tumor and circumferential resection margin was good, with a mean difference of -0.2 mm and an interclass correlation coefficient of 0.74. MRI was not useful for gauging disease activity of persistent abnormalities in mucinous tumors that often represented inactive mucin lakes. CONCLUSION: Decreases in tumor size and nodal downstaging can be seen on MRI after chemoradiation therapy in approximately two thirds of patients. The surgically more relevant parameter--distance between tumor and circumferential resection margin--can be accurately predicted. Errors were caused by the presence of considerable tumor, rectal wall fibrosis, and mucinous tumors.

Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy.

BACKGROUND: An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL) has now been robustly established. In order to estimate the dose-response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. METHODS: For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. RESULTS: The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8-37.2), or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74-0.95)). The absolute agreement intra-class correlation coefficient (ICC) for inter-method variation was 0.59 (95% CI: 0.37-0.75), indicating (nearly) good agreement. There were no systematic differences in the dose estimates between observers or methods. CONCLUSION: Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for.

A 2-year-old boy with hemolytic uremic syndrome and pneumocephalus.

Clostridium septicum infection following hemolytic uremic syndrome is rare and carries a poor prognosis, especially when the brain is involved. We report a case of a previously healthy 2-year-old boy who presented with two days of anuria and bloody diarrhea. He was admitted to the local children's hospital with a diagnosis of hemolytic uremic syndrome, presumably secondary to E. coli O157. He soon required intubation and was noted to have fixed and dilated pupils. Head CT revealed left frontal subcortical white matter vasogenic edema and scattered pockets of pneumocephalus. The patient expired 14 hours after admission. Antemortem blood cultures grew C. septicum. Gross pathologic examination of the brain revealed a large intraparenchymal cerebral hemorrhage in the left frontal and parietal lobes. There was extensive cystic changes as well. Microscopic examination revealed vacuolization and diffuse colonization with rod-shaped bacteria, but without the expected tissue response. There have been only six previously reported cases of C. septicum infection following hemolytic uremic syndrome, four of which had brain involvement. Mortality rate is high, with the only known survivor among those with brain involvement having a brain abscess rather than diffuse pneumocephalus.

The normal post-surgical anatomy of the male pelvis following radical prostatectomy as assessed by magnetic resonance imaging.

The magnetic resonance imaging (MRI) appearances of recurrent prostate cancer following radical prostatectomy have been documented in the radiology literature; however little has been written on the range of normal post-operative appearances. Common routes of surgical access for radical prostatectomy include retropubic and transperineal, although newer minimally invasive methods are gaining increasing acceptance. Specifically the range of appearances of the anastomotic site, the prostatic bed, the position of the bladder base, periurethral tissue, levator sling, rectum and residual seminal vesicles (if present) are demonstrated. A non-enhancing low signal nodule is frequently seen at the vesicourethral anastomosis or within the seminal vesicle remnant and usually represents fibrosis. Appearances following different surgical accesses do not differ tremendously, although the retropubic fat pad is reduced or absent following a retropubic approach. Anterior rectal-wall scarring may be present following a transperineal approach. Other post-surgical findings that may mimic disease include a lymphocoele and injected bladder-neck bulking agent. Many patients referred for MRI following radical prostatectomy will have a pathological study showing disease recurrence, although in non-pathological studies the radiological features can differ significantly. It is important for the radiologist to be aware of the spectrum of normal post-surgical appearances so not to confuse these with locally recurrent disease.