Abstract:Nephrogenic adenoma of the urinary bladder, where they present most frequently, are typically confined to the lamina propria but can on occasion focally involve the superficial muscularis propria. Less commonly, nephrogenic adenoma involves the renal pelvis and ureter where again they almost always only involve the lamina propria. We identified 3 consult cases in which tubules of nephrogenic adenoma extensively involved the muscularis propria and focally infiltrated the perinephric adipose tissue, for which th… Show more
“…Nephrogenic adenoma can recur after resection and rarely presents with perinephric adipose tissue involvement 13. One of our patients with a history of high-grade invasive urothelial carcinoma developed a classic nephrogenic adenoma followed by recurrent fibromyxoid nephrogenic adenoma.…”
Section: Discussionmentioning
confidence: 71%
“…Nephrogenic adenoma can recur after resection and rarely presents with perinephric adipose tissue involvement. 13 One of our patients with a history of high-grade invasive urothelial carcinoma developed a classic nephrogenic adenoma followed by recurrent fibromyxoid nephrogenic adenoma. The recurrent fibromyxoid nephrogenic adenoma involved the muscularis propria, which could potentially have been misdiagnosed as muscularis propria invasion by carcinoma, leading to overstaging and possible overtreatment.…”
Nephrogenic adenoma is a benign epithelial lesion of the genitourinary tract that arises from the reimplantation and proliferation of shed renal tubular cells in areas of urothelial injury and denudation. Fibromyxoid nephrogenic adenoma is a rare variant that consists of compressed spindle-shaped renal epithelial cells in a fibromyxoid background. Only 14 observations of this variant are reported in the literature. We performed a retrospective analysis of fibromyxoid nephrogenic adenomas from 3 large reference centers. We identified 43 lesions in 6 women and 36 men (2 in 1 man) with a median age of 72 years (range, 31 to 94 y). Median lesion size was 0.7 cm (range, 0.2 to 5 cm). Nephrogenic adenomas were in the bladder (n=15), prostate/prostatic urethra (n=14), kidney (n=7), ureter (n=3), penile urethra (n=3), and urethral diverticulum (n=1). One of the kidney lesions developed in an end-stage kidney and radiologically mimicked cancer. Of 37 patients with information, 36 had predisposing conditions including prior biopsy, transurethral resection of bladder tumor, resection, Foley catheter, BCG treatment, urinary stones, (chemo)radiation, or diverticulum. Only 4/37 (10.8%) had a history of prior irradiation. Fifteen lesions had pure fibromyxoid morphology and 28 were admixed classic and fibromyxoid patterns. Three nephrogenic adenomas involved prostatic stroma, 3 renal sinus fat, 2 muscularis propria (1 bladder, 1 renal pelvis), 1 perinephric fat, and 1 corpus spongiosum. Ten fibromyxoid nephrogenic adenomas were intermixed with urothelial carcinoma, 1 with prostate adenocarcinoma, and 1 with malignant melanoma. By immunohistochemistry, PAX8 was positive in all the examined lesions (n=31). Napsin A was negative in all examined fibromyxoid nephrogenic adenomas (n=30). Twenty of them had classic nephrogenic adenoma component which was positive for napsin A. Similar to classic nephrogenic adenoma, fibromyxoid nephrogenic adenoma can occur anywhere along the urinary tract and is associated with a prior history that causes urothelial injury. In nearly a quarter of the cases, fibromyxoid nephrogenic adenoma extended beyond the lamina propria. Unlike previously suggested, fibromyxoid nephrogenic adenoma is not specifically related to prior radiation therapy. Awareness of this variant is important to avoid misdiagnosis and overtreatment.
“…Nephrogenic adenoma can recur after resection and rarely presents with perinephric adipose tissue involvement 13. One of our patients with a history of high-grade invasive urothelial carcinoma developed a classic nephrogenic adenoma followed by recurrent fibromyxoid nephrogenic adenoma.…”
Section: Discussionmentioning
confidence: 71%
“…Nephrogenic adenoma can recur after resection and rarely presents with perinephric adipose tissue involvement. 13 One of our patients with a history of high-grade invasive urothelial carcinoma developed a classic nephrogenic adenoma followed by recurrent fibromyxoid nephrogenic adenoma. The recurrent fibromyxoid nephrogenic adenoma involved the muscularis propria, which could potentially have been misdiagnosed as muscularis propria invasion by carcinoma, leading to overstaging and possible overtreatment.…”
Nephrogenic adenoma is a benign epithelial lesion of the genitourinary tract that arises from the reimplantation and proliferation of shed renal tubular cells in areas of urothelial injury and denudation. Fibromyxoid nephrogenic adenoma is a rare variant that consists of compressed spindle-shaped renal epithelial cells in a fibromyxoid background. Only 14 observations of this variant are reported in the literature. We performed a retrospective analysis of fibromyxoid nephrogenic adenomas from 3 large reference centers. We identified 43 lesions in 6 women and 36 men (2 in 1 man) with a median age of 72 years (range, 31 to 94 y). Median lesion size was 0.7 cm (range, 0.2 to 5 cm). Nephrogenic adenomas were in the bladder (n=15), prostate/prostatic urethra (n=14), kidney (n=7), ureter (n=3), penile urethra (n=3), and urethral diverticulum (n=1). One of the kidney lesions developed in an end-stage kidney and radiologically mimicked cancer. Of 37 patients with information, 36 had predisposing conditions including prior biopsy, transurethral resection of bladder tumor, resection, Foley catheter, BCG treatment, urinary stones, (chemo)radiation, or diverticulum. Only 4/37 (10.8%) had a history of prior irradiation. Fifteen lesions had pure fibromyxoid morphology and 28 were admixed classic and fibromyxoid patterns. Three nephrogenic adenomas involved prostatic stroma, 3 renal sinus fat, 2 muscularis propria (1 bladder, 1 renal pelvis), 1 perinephric fat, and 1 corpus spongiosum. Ten fibromyxoid nephrogenic adenomas were intermixed with urothelial carcinoma, 1 with prostate adenocarcinoma, and 1 with malignant melanoma. By immunohistochemistry, PAX8 was positive in all the examined lesions (n=31). Napsin A was negative in all examined fibromyxoid nephrogenic adenomas (n=30). Twenty of them had classic nephrogenic adenoma component which was positive for napsin A. Similar to classic nephrogenic adenoma, fibromyxoid nephrogenic adenoma can occur anywhere along the urinary tract and is associated with a prior history that causes urothelial injury. In nearly a quarter of the cases, fibromyxoid nephrogenic adenoma extended beyond the lamina propria. Unlike previously suggested, fibromyxoid nephrogenic adenoma is not specifically related to prior radiation therapy. Awareness of this variant is important to avoid misdiagnosis and overtreatment.
“…However, there are also reports of NA infiltrating deep into the perinephric adipose tissue, which should be paid more attention by pathologists. [6] NA hardly develops into malignant progression and metastasis, but it has been reported that bladder NA could transform into moderately differentiated bladder adenocarcinoma after repeated resection of the lesion. [29] Hartmann et al [7] also reported that a 70-yearold female patient with bladder NA subsequently progressed to clear cell adenocarcinoma after multiple recurrences.…”
Section: Discussionmentioning
confidence: 99%
“…[5] In addition, NA tends to perinephric adipose tissue infiltration and malignant transformation, which needs to be considered by the clinicians. [6,7] Thus, regular followup examinations post-operation are essential for patients with NA. Herein, we report for the first time a 46-year-old male patient presenting with painless gross hematuria, with no predisposing factors of renal pelvis NA, whose diagnosis was confirmed by histopathology and immunohistochemistry.…”
Rationale:
Nephrogenic adenoma (NA) is a rare benign lesion of the urinary tract, which rarely occurs in the renal pelvis. Only 19 cases have been reported in the literature. However, there is no detailed report on the clinicopathological features of NA of the renal pelvis.
Patient concerns:
This case report describes a 46-year-old male patient who was admitted to the hospital for one month because of painless gross hematuria with blood clots. He had a history of hyperuricemia and a family history of gastric cancer.
Diagnoses:
NA of the renal pelvis was diagnosed pathologically and immunohistochemical.
Interventions:
The patient underwent laparoscopic nephroureterectomy.
Outcomes:
The patient recovered well after the operation with no discomfort. In addition, we followed up with the patient regularly post-discharge (approximately 20 months). There were no obvious abnormalities in the results of routine urine culture, computed tomography scan of the abdomen, and cystoscopy during the follow-up period, and the symptoms disappeared completely and did not recur.
Lessons:
NA of the renal pelvis is extremely rare in the clinic, which can be easily misdiagnosed and overtreated. However, for pathological diagnosis of this disease, specific immunohistochemical staining for preoperative biopsy was reported to be significant, which should be considered by the urologists and pathologists.
“…These findings supported the diagnosis of nephrogenic adenoma. 2 Fig. 3 Pathological examination of an ureteroscopic biopsy revealed an adenoid tubular structure consisting of a single layer of cuboidal epithelium in the lamina propria of the urothelium.…”
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