Flexible tantalum stents: Effects in the stenotic canine urethra

Purpose Evaluate the effects of flexible tantalum stents (Strecker) implanted into stenotic canine urethras.Methods Eight conditioned, adult, German shepherd dogs, weighing 30–40 kg, were used. Strictures were created surgically in the bulbar urethra just proximal to the os penis. Two months postsurgery, strictures were documented radiographically and then balloon dilated. Following dilatation, a single Strecker stent was placed across the stricture. Stents were 7 mm in expanded diameter and either 2 or 4 cm in length. Retrograde urethrography was performed immediately after stent placement and then biweekly for up to 12 months. Two dogs were sacrificed at 2, 4, 6, and 12 months post-stenting, and necropsy was performed. The urethra was excised, fixed, and examined by scanning electron and light microscopy.Results Clinical success was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4–6 weeks after stent placement and was most pronounced at 4–6 months. Mucosal folds were found between the stent struts. Restenosis occurred at the distal end of the stent in one dog. Histological alterations were noted in the deeper layers of the urethral wall.Conclusion Strecker stents were well tolerated in all animals and seem useful for the treatment of urethral strictures.Presented at CIRSE Annual Meeting and Postgraduate Course, Budapest, June 20–24, 1993     

Renal cyst pseudoenhancement: evaluation with an anthropomorphic body CT phantom

PURPOSE: To evaluate the feasibility of using a retrievable urethral stent and to evaluate whether granulation tissue resolves after stent removal in a canine urethra. MATERIALS AND METHODS: Polyurethane-covered retrievable 0.10-mm-thick (n = 11) or 0.15-mm-thick (n = 10) nitinol wire stents were placed in the urethras of 20 dogs. In one dog, a second stent was placed in the urethra because of complete migration of the first stent into the urinary bladder. The stents were removed with retrieval hook wires 4 weeks (n = 10) and 8 weeks (n = 10) after placement. Fourteen dogs were sacrificed just after stent removal, and the other six dogs were sacrificed 2 weeks after stent removal. Information concerning procedure success, stent migration, and tissue response was obtained. RESULTS: Stent placement was technically successful in all dogs. Follow-up urethrograms showed partial (n = 4) or complete (n = 1) stent migration. Stent removal failed in two dogs due to partial or complete migration. Granulation tissue was observed at both ends of the stent in 17 dogs. Urethrograms and urethral specimens obtained 2 weeks after stent removal showed diminished granulation tissue and decreased thickness of the papillary projections of the epithelium compared with results obtained immediately after stent removal. CONCLUSION: Although some design modifications are necessary to reduce current complications, the polyurethane-covered retrievable nitinol stent seems feasible for use in the urethra. Stent-induced granulation tissue formation improved after stent removal.     

Prostatic urethra dilatation with the Gianturco self-expanding metallic stent: a feasibility study in cadaver specimens and dogs.

In an effort to develop a transcatheter technique for dilatation of the prostatic urethra without the use of balloons, the feasibility of using Gianturco self-expanding stents was evaluated. Initially, eight human cadaveric prostatic urethras were stented to evaluate the ability of the stent to dilate the lumen. In all cases, the device attained its unconstrained diameter immediately on placement. Subsequently, stents were placed in the prostatic urethra of 12 dogs and followed up for 1 month (four dogs), 3 months (one dog), and 6 months (seven dogs). Five bare straight-end prostheses, one nylon-covered straight-end device, and six flared-end stents were used. Three of the bare straight-end stents migrated during the follow-up, whereas the nylon-covered and flared-end stents did not. Stent diameters greater than 1.3 times the urethral diameter caused moderate to marked edema and inflammation. After 6 months, white deposits were found on the solder points, presumably from electrolysis. Our experience suggests that placement of Gianturco self-expanding stents may be a useful method of dilating and maintaining the luminal diameter of the prostatic urethra, although care must be taken to select the proper stent size.     

Evaluation of the Effects of Temporary Covered Nitinol Stent Placement in the Prostatic Urethra: Short-Term Study in the Canine Model

Purpose To evaluate the effect of temporary stent placement on the canine prostatic urethra. Methods Retrievable PTFE-covered nitinol stents were placed in the prostatic urethras of 8 beagle dogs under fluoroscopic guidance. Retrograde urethrography was obtained before and after stenting. Retrograde urethrography and endoscopy were performed 1 and 2 months after deployment. The endoscopic degree of hyperplasia was rated on a scale of 0 to 4 (0 = absence, 4 = occlusion). On day 60, stents were removed and urethrography was performed immediately before euthanasia. Pathologic analysis was performed to determine the degree of glandular atrophy, periurethral fibrosis, and urethral dilation. Results Stent deployment was technically successful in 7 animals, and failed in 1 dog due to a narrow urethral lumen. Complete migration was seen in 2 animals at 1 month, and an additional stent was deployed. On day 30, endoscopy showed slight hyperplasia (grade 1) in 3 animals. On day 60, moderate hyperplasia (grade 2) was evidenced in 4 cases. No impairment of urinary flow was seen during follow-up. Retrieval was technically easy to perform, and was successful in all dogs. The major histologic findings were chronic inflammatory cell infiltrates; prostate glandular atrophy, with a mean value of 1.86 (SD 0.90); periurethral fibrosis, with a mean ratio of 29.37 (SD 10.41); and dilatation of the prostatic urethra, with a mean ratio of 6.75 (SD 3.22). Conclusion Temporary prostatic stent placement in dogs is safe and feasible, causing marked enlargement of the prostatic urethral lumen. Retrievable covered stents may therefore be an option for bladder outlet obstruction management in men.     

Tissue hyperplasia: influence of a paclitaxel-eluting covered stent--preliminary study in a canine urethral model

PURPOSE: To evaluate a paclitaxel-eluting covered stent in reduction of tissue hyperplasia after stent placement in a canine urethral model. MATERIALS AND METHODS: Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. Twenty paclitaxel-eluting polyurethane-covered stents (drug stents) and 20 polyurethane-covered stents (control stents) were placed alternately between the proximal and distal urethra in 20 male dogs. The dose of paclitaxel was approximately 1800 mug in each drug stent but absent in each control stent. Dogs were sacrificed either 4 (n = 10) or 8 (n = 10) weeks after stent placement. The percentage diameter of stenosis was assessed with follow-up retrograde urethrography and histologic findings obtained after sacrifice and compared between drug stents and control stents and between the proximal and the distal urethra. RESULTS: Two drug stents partially migrated during retrograde urethrography immediately after stent placement; they were removed and replaced with a second stent during the same procedure. There was a strong tendency toward a lower percentage diameter of stenosis and numeric mean values of the four histologic findings, which indicates less formation of tissue hyperplasia in the proximal urethra than in the distal urethra. In particular, thickness of the papillary projection denoting the entire thickness of hyperplastic reaction was significantly less in drug stents than in control stents in the proximal urethra in the 8-week group (P = .016, Mann-Whitney U test). CONCLUSION: Local delivery of paclitaxel via covered stents has the potential to reduce tissue hyperplasia secondary to stent placement in a canine urethral model. With stent placement, there are distinct differences of tissue hyperplasia between the proximal and distal urethra.     

Is a flared stent effective for decreasing stent migration in canine prostatic urethra?

Background: Prostatic urethral stents are effective in relieving obstructions caused by benign prostatic hyperplasia (BPH). However, migration of these stents occurs frequently.

Purpose: To evaluate the efficacy of a flared stent for decreasing the migration rate in comparison with a straight stent in a canine prostatic urethral model.

Material and Methods: The flared stent (15 mm in diameter and 20 mm in length) was flared up to 19 mm at both ends to prevent migration. A straight stent with the same size was straight without flaring. Both stents were made of a nitinol wire filament and covered with an expanded polytetrafluoroethylene (ePTFE) membrane. The flared stent was inserted in the prostatic urethra of 10 dogs (group 1) and the straight stent in the prostatic urethra of 12 dogs (group 2). Follow-up retrograde urethrography (RUG) was performed 1, 4, and 8 weeks after stent placement. Fisher's exact test was used to compare the migration rate between the two groups. When stent migration occurred during the follow-up period, the same type of stent was inserted again.

Results: Three of 10 (30.0%) flared stents migrated into the urinary bladder between 1 week and 4 weeks after placement. Seven of 12 (58.3%) straight stents migrated into the urinary bladder 1 (n = 3), 4 (n = 1), and 8 (n = 3) weeks following placement. The flared stent group showed lower migration rate than the straight stent group, but the migration rate did not reach statistical significance (P = 0.231). After the second stent placement, one of three (33.3%) flared stents migrated again after 4 weeks and two of seven straight stents (28.6%) after 1 week.

Conclusion: Although the migration rate was not statistically significant, the flaring of the stent seemed to reduce the migration rate in comparison with straight stents in a canine prostatic urethral model. However, the migration rate of the flared stent was still high, and further developments are required to decrease migration rate.     

Polydioxanone Biodegradable Stent Placement in a Canine Urethral Model: Analysis of Inflammatory Reaction and Biodegradation

PurposeTo investigate the inflammatory reaction and perform quantitative analysis of biodegradation after placement of a polydioxanone (PDO) biodegradable stent in a canine urethral model.Materials and MethodsPDO biodegradable stents were placed in the proximal and distal urethra of nine male mongrel dogs. The dogs were euthanized 4 weeks (group A; n = 3), 8 weeks (group B; n = 3), or 12 weeks (group C; n = 3) after stent placement. The luminal diameter of the stent-implanted urethra was assessed by follow-up retrograde urethrography, and histologic findings were obtained after the dogs were killed. Stents were removed after euthanasia, and their surface morphology and molecular weight were evaluated. Hematologic examination was performed to evaluate inflammatory reaction.ResultsStent placement was technically successful in all dogs. The average luminal diameter gradually decreased. The average number of epithelial layers (2.93 vs 4.42; P < .001), the average thickness of papillary projection (0.80 mm vs 1.28 mm; P < .001), and the average thickness of submucosal fibrosis (0.34 mm vs 0.49 mm ; P < .001) were significantly increased in group B versus group A. There were no significant differences between group B and group C. The average inflammatory cell infiltration did not differ significantly in the three groups. Molecular weight losses were 54% in group A and 84% in group B. In group C, PDO stents were completely decomposed.ConclusionsAn experimental study in a canine urethral model has demonstrated acceptable inflammatory reaction with gradually increasing granulation tissue but no luminal obstruction within 12 weeks.     

An animal experiment on arterial wall reaction to stents coated with gold, silver and copper]

Expandable metallic stents coated with gold, silver, and copper, and bare stainless steel stents were implanted into the abdominal aorta of eight dogs to determine their effect on the vessel wall. The animals were observed for two weeks. Abdominal angiograms were taken every week. The dogs were then killed for macroscopic and histopathological examination. The results were as follows. (1) The stents coated with gold and the noncoated stainless steel stents showed less histopathologic change than the other stents. (2) The stents coated with copper were associated with severe erosion of the vessel wall and marked thrombus formation.     

Echotomographic evaluation of the anterior urethra

A simple method of sonographic (US) evaluation of penile and bulbous urethra is reported. Twenty-three dysuric patients were examined. They were divided into 2 groups according to their pathology. The US patterns of normal urethra were evaluated in 10 patients (first group) with no obstructive lesions. Urethral and periurethral structures were examined in 13 patients (second group) with urethral obstructive pathology. All patients underwent conventional cystourethrography. The diagnostic parameters considered were urethral gauge and thickness, echogenicity of the urethral wall, and Cowper's glands. US evaluation of obstructive lesions provided the same findings as conventional radiological techniques. Moreover, US allowed the evaluation of both thickness and echogenicity of the urethral wall, and of normal/injured Cowper's glands.     

X线监视下经尿道植入支架治疗高龄前列腺增生症

目的评价植入网状记忆合金支架治疗高龄前列腺增生症尿道狭窄的临床效果和可行性。方法47例患者,年龄72~93岁,平均78.3岁,排尿困难7~21年。1%利多卡因尿道黏膜麻醉,DSA引导下经尿道将支架放置在前列腺尿道最狭窄处。结果47例患者均一次治疗成功(100%),其中43例支架植入后立即自行排尿,排尿通畅。本组无1例出现尿道再狭窄和结石等情况,排尿通畅率100%。结论记忆合金网状支架治疗前列腺增生引起的排尿困难临床疗效显著,值得临床推广应用。     

Effects of a holmium-166 incorporated covered stent placement in normal canine common bile ducts

PURPOSE: A specially designed self-expandable covered metallic stent incorporated with beta-emitting radioisotope, Holmium-166 (Ho-166), was developed for delivering intraluminal brachytherapy as well as for internal bile drainage in malignant biliary stricture. The purpose of the study was to demonstrate the safety and tissue response of the radioactive metallic stent on the normal canine common bile duct (CBD) prior to the clinical application. MATERIALS AND METHODS: Nitinol self-expandable stents (diameter; 4 mm, length; 20 mm) were covered with polyurethane membrane (50 microm thick) containing 21 to 135 muCi of Ho-166 (mean, 77.9 microCi). To prevent migration of stent, the membrane covered only the middle 1 cm of the stent and the ends of the stent were left uncovered. The stents were placed in the CBD of 20 healthy beagle dogs. For control, non-radioactive covered stents were placed in another three dogs. The dogs were killed 3 to 6 months after stent insertion and histopathologic examination of CBD was performed. RESULTS: There was no stent migration in all cases. Varying degrees of papillary mucosal hyperplasia leading to significant narrowing of the lumen was observed within the lumen of the bare portion and under the mucosal surface of the non-radioactive covered stents. However, fibrosis was noted in Ho-166 coated area, instead of mucosal hyperplasia. Severity of fibrosis was correlated with estimated radiation dose. Despite high dose, there was no perforation of CBD wall. The membrane of Ho-166 coat was disrupted in some cases of 6 months follow-up. CONCLUSIONS: Holmium-166 incorporated covered stents demonstrated fibrosis of CBD wall and inhibition of ingrowth of mucosal hyperplasia without serious complication such as perforation, while control group showed severe mucosal hyperplasia.     

Evaluation of the Anti-migration Effect of Barbed Prostatic Stents: In Vitro Study in Urethra-mimicking Bovine Pericardium Phantoms

Purpose

This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models.

Methods

Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push–pull gauge system at a fixed rate (2 mm/s).

Results

Significant differences in AMF among the three stent types were detected (P < 0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents.

Conclusions

The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.     

Percutaneous endovascular stents: an experimental evaluation

Percutaneous, expanding, endovascular stents were constructed of stainless steel wire formed in a zig-zag pattern. Stents were placed for varying periods of time in the jugular vein, vena cava, and abdominal aorta in each of five adult dogs. The dilating force of the stents could be controlled by different wire size, number and angle of wire bends, and stent length. In addition, multiple stents could be placed one inside the other or one after the other, depending on the circumstance. The stents distended the vessels and increased their diameter. No flow defects, luminal narrowing, or occlusion were noted in any of the stented vessels, even after 6 months. Side branches bridged by the stents remained patent and showed no indication of narrowing. Stent wires became encased by a proliferation of the tunica intima where they contacted the vessel wall. Encasement was slower and less extensive in the abdominal aorta. No vascular erosion or clot formation was found to be associated with any of the stents.     

尿道内支架置入术初步实验研究

目的：主要了解尿道粘膜对内支架置入后的反应。材料与方法：雄性犬５条。球囊扩张式钽丝支架（Ｓｔｒｅｃｋｅｒｓｔｅｎｔ），内支架扩张后内径６ｍｍ。先行逆行尿道造影后，支架置入前列腺部位尿道内，术后３天、２周和１个月造影复查，取病理检查。结果：造影复查显示尿道通畅，有１例内支架移位。病理巨检见支架与尿道结合紧密，支架网眼内粘膜增生，镜检示粘膜上皮细胞增生，结缔组织内有炎性细胞浸润及小血管增生，电镜下钽丝表面光滑。结论：粘膜上皮对该内支架无明显炎性反应，适用于前列腺成形术。     

闭合性尿道损伤的急症处理（附36例报告）

目的 探讨闭合性尿道损伤的治疗。方法 回顾分析36例本病患者的临床资料。前尿道损伤13例，球部损伤14例，后尿道损伤9例。14例尿道挫伤行留置尿管＋抗炎治疗；部分断裂14例，6例留置尿管，6例尿道会师，2例尿道吻合；完全断裂8例，尿道会师2例，尿道吻合4例，膀胱单纯造瘘2例。结果 经手术和药物治疗后效果满意，并发症少。结论 对闭合性尿道损伤，根据损伤的程度和部位选择合理的治疗方法，可取得较好效果。     

Comparison of a New Polytetrafluoroethylene-Covered Metallic Stent to a Noncovered Stent in Canine Ureters

The aim of this study was to determine the feasibility of using a newly designed polytetrafluoroethylene (PTFE)-covered metallic stent in the ureter by comparing its effectiveness with that of the noncovered stent in a canine model. We placed 14 stents in the ureters of seven mongrel dogs that weighed 30–40 kg each. The covered and noncovered stents were deployed in the right and left ureters, respectively, of six dogs. In the seventh dog, a covered stent and a double-J catheter were inserted in the right ureter, and a covered stent only was inserted in the left ureter. The first six dogs were sacrificed at 5, 10, and 15 weeks after deployment of the stents (two for each follow-up period), and the seventh dog was sacrificed at 30 weeks. There was no migration or poor expansion of any of the stents observed on plain radiography. On intravenous pyelogram and retrograde pyelogram, all of the covered stents at each follow-up period had patent lumens at the stented segments without hydronephrosis, and the passage of contrast material through it was well preserved. The noncovered stents in the dogs sacrificed at 5 and 10 weeks and one of the two dogs sacrificed at 15 weeks showed near-complete occlusion of the stent lumen due to ingrowth of the soft tissue, and severe hydronephrosis was also noted. The noncovered stent in the other dog sacrificed at 15 weeks showed the passage of contrast material without hydronephrosis, but the lumen of the stent was still nearly occluded by the soft tissue. There was no evidence of hydronephrosis or passage disturbance of the contrast material in both ureters of the dog sacrificed at 30 weeks. We conclude that the newly designed PTFE-covered stent effectively prevented the luminal occlusion caused by urothelial hyperplasia compared to the near-total occlusion of the noncovered stents, and no migration of the covered stents was noted.     

Experimental study of endotracheal expandable metallic stent placement

Various types of Gianturco zig-zag wire stents were implanted into the trachea of three dogs in order to evaluate the suitable conditions of the endotracheal wire stent. The stents were constructed of 0.018, 0.016 and 0.013 inch stainless steel wire respectively. The relaxed diameter of the stents was 3.0 cm and their length were 2 cm, 3 cm, and 4 cm respectively. The stent of 2 cm in length and constructed of 0.013 inch showed minimum pathologic changes to the trachea of the dog compared to the other stents, and also showed the covering of ciliated, columnar epithelium over the stent surface. The experimental data showed that it was possible to use the stent in the tracheobronchial tree of dogs and also showed a potential clinical application.     

兔尿道细胞外基质修复尿道创伤缺损及组织相容性研究

目的 探讨尿道细胞外基质修复尿道创伤缺损的疗效及其组织相容性. 方法 实验组20只家兔手术切除一段长约1.0～1.5 cm的尿道,人工造成尿道缺损模型.再用一段等长的尿道细胞外基质修复尿道缺损.另设对照组(仅在游离尿道后关闭切口,10只)和异体尿道移植组(配对互换移植,10只).采用淋巴细胞转化实验及术后1,2,3,4周从兔耳缘静脉取血,应用流式细胞仪检测样本中T淋巴细胞亚群CD4+、CD8+及CD4+/CD8+动态变化,评估术后受体的免疫反应状态;术后10 d、3,6及24周取修复段尿道,行组织学观察;术后24周行尿道造影、尿道镜及尿流动力学检查. 结果 实验组术后淋巴细胞刺激指数及外周血淋巴细胞亚群CD4+、CD8+及CD4+/CD8+比值和对照组比较,差异无统计学意义;但异体尿道移植组则高于对照组(P<0.05).术后3周起实验组上皮细胞覆盖细胞外基质的整个管腔;24周尿道平滑肌数量明显增多,接近正常的尿道组织结构.尿道造影及尿道镜检查显示尿道基质管壁光滑通畅.尿流动力学检测显示实验组与对照组比较,差异无统计学意义. 结论 尿道细胞外基质具有较好的组织相容性,是一种安全有效的尿道修复材料.     

A seldom case of primary urethral malignant melanoma and breast cancer detected by (18)F-FDG PET/CT

In the 1(st )issue of HJNM for 2012 we read with interest a case where 3 different cancers were detected. Synchronous second malignancy can be incidentally detected in routine fluorine-18-fluoro-deoxy-glucose positron emission tomography/computed tomography ( (18)F-FDG PET/CT) imaging in approximately 1% of cancer patients with lungs being the most frequent site. We report the (18)F-FDG PET/CT scan for staging of the primary malignant melanoma of the urethra and for the detection of another malignancy in the breast in the same patient, since primary malignant melanoma of urethra is very seldom. A 65 years old post-menopausal woman presented with increased frequency of micturition, dysuria and a gradually enlarging mass protruding from the external urethral meatus. Fine needle aspiration cytology (FNAC) performed from the mass revealed malignant melanoma. On cystourethrescopy examination, a 4x4 cm blackish mass was noted at the external urethral meatus with a satellite nodule in the bladder trigone. Contrast enhanced CT (CeCT) of the pelvis showed soft tissue thickening along the urethra infiltrating urinary bladder neck and vagina. Analysis of (18)F-FDG PET/CeCT was performed to assess the extent of the disease. Intensely (18)F-FDG avid soft tissue mass (SUV(max): 20.1) was noticed along the entire length of the urethra with hypermetabolic right inguinal and left external iliac lymph nodes. In addition to (18)F-FDG uptake in the bladder wall and the vaginal wall, intense (18)F-FDG uptake was also seen in two soft tissue nodules in the right breast and in the axillary lymph nodes suggestive of a second primary in the breast. Cytological diagnosis of intraductal breast carcinoma was made after FNAC from the breast nodule. Urethral melanoma was treated with anterior exenteration and ileal conduit. Histopathology confirmed the diagnosis of primary malignant melanoma of urethra infiltrating the urinary bladder and anterior vaginal wall. Postoperative histopathology from the right inguinal and left external iliac lymph nodes revealed metastatic disease. The diagnostic contribution of PET/CT was crucial. Melanotic melanoma cells have a distinctive MRI signal, which may be helpful in diagnosis. In this case whole body MRI could have been of equal value for accurate staging of urethral melanoma, but whole body MRI is a cumbersome procedure and often is not practical. Primary urethral carcinoma is very rare and an annual ageadjusted incidence rate of 4.3 per 106 in males and 1.5 per 106 in females has been reported in USA. Primary malignant melanoma of the urethra is rare, representing less than 1% of all melanomas and 4% of urethral cancers. Furthermore, the incidence of two primary cancers is rare and is reported to be between 0.3% and 4.3%. Primary malignant melanoma of the urethra has a worse prognosis than its cutaneous counterpart, partly due to delayed diagnosis. At the time of diagnosis, urethral melanoma is usually deeply invasive and locally extended to the vagina or vulva or the corpora cavernosa. Inguinal lymph node metastases are present at diagnosis in half of the cases and distant metastases in one third of them. Positron emission tomography demonstrates specificity and accuracy of 94.7% and 73% respectively in detecting lymph nodal metastases. Sensitivity, specificity and accuracy of (18)F-FDG PET/CT in detecting metastases in high risk patients were 85%, 96%, 91% while for (18)F-FDG PET/CT with dedicated CT interpretation were 98%, % and 96%, respectively. Recently, the role of (18)F-FDG PET/CT in treatment response evaluation of melanoma patients has also been demonstrated. Incidental (18)F-FDG uptake in the breasts is rare, and the lesion may be malignant in up to 57% of the cases. To our knowledge no published literature is available on synchronous breast carcinoma and urethral melanoma. The reason why some patients are more prone to develop multiple cancers remains obscure. One possibility may be of a genetic predisposition linking the two cancers. Research suggests that mutations in CDKN2A, a gene that indicates high risk of developing melanoma, also puts carriers at an up to 3.8 times greater risk of breast cancer. Similarly, mutations in the gene of breast cancer susceptibility, BRCA2, increase carriers' risk of melanoma by as much as 2.58 times. In conclusion, we describe a case of two primary carcinomas: a unique urethral malignant melanoma and a breast carcinoma, detected and staged by (18)F-FDG PET/CT.     

小儿盆腔及泌尿生殖系横纹肌肉瘤的影像诊断

目的探讨儿童盆腔及泌尿生殖系横纹肌肉瘤(RMS)的尿路造影和CT表现及其诊断价值。资料与方法回顾性分析20例经手术及活检病理证实的原发于盆腔及泌尿生殖系RMS的影像学资料。其中10例经静脉肾盂造影(IVP)检查,3例经膀胱尿道造影(VCUG)检查,10例经CT检查,1例经MRI检查。结果8例膀胱RMS的IVP、CT表现为膀胱内葡萄状充盈缺损,膀胱颈部与耻骨联合间距增宽,VCUG可见肿物延伸至后尿道;4例前列腺RMS表现为后尿道肿物压迫膀胱颈部并使其抬高、环绕尿道的盆底部包块。6例盆腔RMS IVP及CT表现为盆腔包块,压迫膀胱移位、变形,膀胱壁轻度浸润不规则,输尿管下段浸润者可有轻度输尿管及肾盂积水。1例尿道RMS表现为尿道内充盈缺损,1例阴道RMS,IVP表现为膀胱颈部充盈缺损。结论IVP及VCUG能明确诊断原发于膀胱、前列腺、尿道的RMS及上尿路继发病变;CT及MR可进一步了解起自阴道、前列腺、盆腔的RMS及其与周围器官的关系。