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Biomedical subjects

Ronald L Yap

Publications and source records attributed to Ronald L Yap.

10 recordsLinked to original sources
PubMed2006

Pathological characteristics of prostate cancer detected through prostate specific antigen based screening.

PURPOSE: Since the introduction of PSA testing for CaP, there has been an increase in CaP detection. However, it is uncertain to what extent clinically insignificant tumors are being diagnosed and treated. In a large, community based population we determined the pathological characteristics of screening detected cancers. MATERIALS AND METHODS: From 1989 to 2001, 35,661 men were enrolled in a longitudinal prostate cancer screening study. Data were available on 3,492 of the 3,568 men (98%) diagnosed with CaP during this study period. Radical prostatectomy was performed in 2,254 men (63%). Clinical stage, Gleason score and pathological analysis were recorded and analyzed in the context of preoperative PSA, digital rectal examination findings, PSA velocity and the year of cancer detection. RESULTS: CaP was detected in 10% of men. Virtually all cases were clinically localized (99.8%) and approximately 70% treated with radical prostatectomy were pathologically organ confined disease. Fewer than 10% of tumors would be considered clinically insignificant based on 2 previously published pathological criteria. CONCLUSIONS: Compared to the high prevalence of CaP found in autopsy studies there is a lower detection rate using current screening protocols. Although the outcomes are unknown if these tumors had been left untreated, the majority met pathological criteria for significant cancer.

Adult↗
PubMed2005

Inflammatory pseudotumor of the testis: a novel presentation of acute retroviral syndrome.

Inflammatory pseudotumors are a rare entity, the etiology of which is not well understood. It has been postulated that these non-neoplastic lesions are the result of a reaction to trauma, surgery, infection or local irritation, though in many cases an underlying cause is never found. In this case, a 30-year-old man with previously undiagnosed human immunodeficiency virus presented with a 2-week history of painless right testicular mass measuring 1 x 1 cm. The patient underwent right radical orchiectomy with histopathological analysis revealing an inflammatory pseudotumor of the testis. Further work up pointed to acute retroviral syndrome as the likely cause.

Adult↗
PubMed2004

Xanthogranulomatous orchitis.

Xanthogranulomatous inflammation is an uncommon process that is usually associated with severe renal infection. We report a case of a 64-year-old man with xanthogranulomatous inflammation in the testis who presented with contralateral epididymoorchitis and a painless testicular mass. Only two prior cases of xanthogranulomatous orchitis have been reported. This case highlights the need for a broad differential diagnosis when approaching testicular masses, particularly in the setting of coincident infection.

Diagnosis, Differential↗
PubMed2004

Retrieval of migrated ureteral stent by intussusception of ureteral balloon dilator tip.

A vexing complication of ureteral stent placement is inadvertent proximal migration. The retrieval of a migrated ureteral stent may be performed using a myriad of techniques but usually requires ureteroscopic extraction. We report a novel, time-efficient technique to capture and reposition a migrated ureteral stent without ureteroscopic manipulation.

Catheterization↗
PubMed2003

Laparoscopic renal cryosurgery: the Northwestern experience.

PURPOSE: Laparoscopic renal cryosurgery provides a minimally invasive alternative for the treatment of small renal lesions of undefined malignant potential. We report on our series of patients treated with laparoscopic renal cryosurgery. MATERIALS AND METHODS: Fifteen patients underwent laparoscopic renal cryoablation of peripheral, exophytic unifocal renal lesions. Patients were managed with a 4-port transperitoneal approach for anteromedial tumors and 3 to 4-port retroperitoneal approach for posterolateral tumors. All lesions were biopsied and sent to pathology for permanent section. A 4.8 mm cryoprobe (CMS cryoprobe, 4.8 mm x 2 cm x 40 cm, Cryomedical Sciences Inc., Ewing, New Jersey) was placed into the tumor using visual and ultrasonographic guidance, and a double freeze-passive thaw cycle was performed. The iceball was extended at least 1 cm beyond the tumor margin under ultrasound guidance. Followup biopsies were performed on all consenting patients with renal cell carcinoma at least 3 months after cryosurgery was performed. RESULTS: Laparoscopic renal cryosurgery was successfully performed on all 15 patients (6 male and 9 female). Of the 15 patients 10 had renal cell carcinoma. Mean age was 68.5 years (range 49 to 86). Mean tumor size was 2.15 cm (range 1.2 to 3.2) and mean estimated blood loss was 67 cc (range 15 to 125). There were 2 perioperative complications. Mean hospital stay was 3.5 days (range 1 to 11). Patients returned to work after 16.5 days (range 7 to 28). Radiographic followup revealed stable cryoablative lesions in all patients. Mean radiographic followup was 453 days (range 147 to 816). Mean preoperative creatinine was 1.25 mg/dl (range 0.8 to 4.3) and mean postoperative creatinine obtained 1 month postoperatively was 1.36 (range 0.8 to 4.8). There was 1 treatment failure, although another patient had a positive biopsy outside the ablated area. The failure occurred in the largest tumor treated (3.2 cm) and was due to incomplete treatment of the periphery of the lesion. The other patient had a successfully treated tumor but a positive followup biopsy due to multifocal papillary renal cell carcinoma and required nephrectomy. CONCLUSIONS: Laparoscopic renal cryosurgery appears to be a safe and effective minimally invasive alternative for the treatment of small renal masses. Careful selection of patients with lesions that are less than 3.0 cm and close monitoring of the iceball is necessary to treat these patients successfully.

Aged↗
PubMed2002

Topical agents and erectile dysfunction: is there a place?

Despite the proven efficacy of oral therapy for erectile dysfunction (ED), some patients are unable to take these medications because of drug interactions (ie, sildenafil and nitroglycerin) or a lack of response. Topical agents represent another minimally invasive option for the treatment of ED. This review discusses the impediments to effective topical therapy and examines the developmental status of several candidate drugs. Although still in the investigative stage, topical medications can be another tool in the urologist's armamentarium against ED.

Administration, Topical↗