IgG4-related inflammatory pseudotumor of the renal pelvis involving renal parenchyma, mimicking malignancy.

BACKGROUND: IgG4-related disease is a recently recognized systemic disease characterized by storiform fibrosis with infiltration of IgG4-positive plasma cells. In rare incidences, IgG4-related renal disease can present as a solitary mass lesion at renal pelvis and can pose a diagnostic challenge since these lesions mimic malignancy. Herein, we present a rare case of IgG4-related disease presenting as inflammatory pseudotumor lesion, involving the renal pelvis and also neighboring renal parenchyma. CASE PRESENTATION: A 75-year-old man with no history of IgG4-related disease underwent computed tomography (CT) scan for evaluation of prostatic cancer. The CT scan incidentally revealed a mass lesion located at the right renal pelvis. Radiologic findings were highly suggestive of malignancy. Therefore, the patient underwent right nephroureterectomy. Microscopically, the mass lesion showed storiform fibrosis with diffuse and intense inflammatory cell infiltration. Infiltrating cells were mainly histiocytes and plasma cells. Tubulointerstitium adjacent to the lesion also showed fibrosis with abundant plasmacytic infiltration. Immunohistochemical staining revealed the presence of IgG4-positive plasma cells in both the mass lesion and tubulointerstitium (mean of 94/HPF per field). CONCLUSION: Considering these findings, we diagnosed the mass lesion as IgG4-related inflammatory pseudotumor of the renal pelvis. In patients with renal pelvic masses, IgG4-related inflammatory pesudotumor should be considered in the differential diagnosis to avoid unnecessary surgical intervention.

Cystic Angiomyolipoma Mimicking Cystic Renal Cell Carcinoma on Computed Tomography Image.

We report on a 44-year-old male patient with cystic angiomyolipoma (AML) simulating cystic renal cell carcinoma on computed tomography (CT). The CT scan showed a 2.8-cm left renal cystic mass with an enhancing solid component. No fat density was identified in the mass. These findings were indicative of a cystic renal cell carcinoma. Robot-assisted laparoscopic partial nephrectomy was performed, but the final histologic result was a cystic AML. Herein, we would review the preoperative CT findings, which could have suggested cystic AML.

Efficacy of Repeated Transrectal Prostate Biopsy in Men Younger Than 50 Years With an Elevated Prostate-Specific Antigen Concentration (>3.0 ng/mL): Risks and Benefits Based on Biopsy Results and Follow-up Status.

PURPOSE: Prostate cancer is rare in men younger than 50 years. Digital rectal examination (DRE) and measurement of prostate-specific antigen (PSA) concentrations are standard screening methods for detecting prostate cancer. We retrospectively investigated the risks and benefits of repeated transrectal ultrasonography-guided prostate needle biopsies in relation to the follow-up status of men younger than 50 years with a consistently high PSA concentration (>3.0 ng/mL). MATERIALS AND METHODS: During the period from January 2000 through February 2013, we reviewed patient's ages, dates of procedures, DRE results, frequencies of biopsies, results of the biopsies, periods of follow-up, PSA concentrations, and prostate volumes in Chonbuk National University Hospital records. We conducted telephone interviews in patients who did not undergo regular follow-up. RESULTS: The mean age of the patients was 44.7 years, and the mean PSA concentration was 8.59 ng/mL (range, 3.04-131 ng/mL) before biopsy. The PSA concentration was significantly different (p<0.001) between the patients with prostate cancer and those with benign prostatic hyperplasia (BPH). Nineteen patients underwent repeated prostate biopsy; however, in only one patient did the pathologic findings indicate a change from BPH to prostate cancer. We identified several complications after transrectal biopsy through an evaluation of follow-up data. CONCLUSIONS: All patients with benign prostatic disease based on their first biopsy were shown to have benign disease based on all repeated biopsies (15.83%), except for one patient; however, several complications were noted after biopsy. Therefore, the risks and benefits of repeated biopsy in young patients should be considered because of the low rate of change from benign to malignant disease despite continuously high PSA concentrations (>3.0 ng/mL).