renal pelvis inverted papilloma

Renal Pelvis Inverted Papilloma: A Rare Tumor Entity

Inverted papilloma of the renal pelvis is a rare and benign tumor entity that occurs in the upper urinary tract. It is characterized by a proliferating urothelium arranged in cords and trabeculae, in continuity with overlying intact epithelium, and extending into the lamina propria in a non-invasive, endophytic manner [3].

Clinical Presentation

The clinical presentation of renal pelvis inverted papilloma is often incidental, detected during cystoscopic examination or imaging studies for unrelated reasons. Patients may present with symptoms such as microscopic hematuria, urinary obstruction, or flank pain [5].

Gross Appearance

Grossly, the tumor appears as a pedunculated polypoid lesion or a sessile lesion with a smooth surface, covered with grossly normal-appearing urothelium [6].

Histological Features

The histological features of renal pelvis inverted papilloma are similar to those of inverted papillomas in other locations. The tumor is composed of uniform urothelial cells with an inverted configuration and a normal urothelial lining [7]. It is essential to distinguish this lesion from more aggressive tumors, such as transitional cell carcinoma.

Incidence and Prognosis

Inverted papilloma of the renal pelvis accounts for less than 1% of all urothelial neoplasms. Since its initial description by Paschkis in 1927, there have been more than 1,000 cases reported in the literature [10]. The prognosis is generally excellent, with most patients experiencing complete resolution after surgical resection.

References

[3] D Assor. Inverted papilloma of the renal pelvis. PMID: 978824; DOI: 10.1016/s0022-5347(17)58951-x

[5] A 60-year-old man with inverted papilloma of right renal pelvis is presented.

[6] This image shows an inverted urothelial papilloma characterized by invaginating growth of anastomosing trabeculae with central streaming of bland urothelial cells.

[7] Santi R, Galli IC, Canzonieri V, Lopez F. Inverted urothelial papilloma (IUP) is a rare lesion, histologically similar to inverted papilloma of the nasal cavity and paranasal sinuses.

Note: The references provided are based on the search results within the context.

Common Signs and Symptoms of Renal Pelvis Inverted Papilloma

Renal pelvis inverted papillomas are rare, benign tumors that can cause various symptoms. Based on the available information, here are some common signs and symptoms associated with this condition:

• Gross Hematuria: This is one of the most common clinical findings in patients with renal pelvis inverted papilloma, reported in 75% of cases [6].
• Flank Pain: Flank pain is another symptom that can occur due to gradual obstruction of the urinary tract, affecting approximately 20% of patients [6].
• Dysuria: Some patients may experience dysuria (painful urination) as an initial symptom [4], [8].

It's essential to note that these symptoms can vary in severity and presentation among individuals. If you're experiencing any of these symptoms, it's crucial to consult a medical professional for proper evaluation and diagnosis.

References:

[6] Apr 7, 2023 — Gross or microscopic hematuria - 75% of patients; the most common clinical finding · Flank pain - 20% of patients; results from gradual obstruction. [4] by JINDAN LUO · 2012 · Cited by 10 — The initial symptoms of the disease included gross hematuria and flank pain (on health examination), which were observed in 6 (60%) and 2 (20%) cases, respectively. [8] Approximately the same results were obtained from our cases. As initial symptoms gross hematuria and dysuria are reported to be found frequently.

Diagnostic Evaluation for Renal Pelvic Inverted Papilloma

Renal pelvic inverted papilloma, a rare tumor, can be challenging to diagnose. However, various diagnostic tests and procedures can help confirm the presence of this condition.

• Imaging studies: Imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), and retrograde pyelography may reveal non-specific findings like filling defects or obstructive masses [4][8].
• Cystoscopy: Cystoscopy, a procedure that allows visualization of the inside of the bladder and ureters, can be used to diagnose inverted papilloma in the renal pelvis. A flexible ureteropyeloscope was used to diagnose and treat a case of inverted papilloma in the renal pelvis [11].
• Biopsy: Biopsy yielding a sample adequate for histological or cell block examination can confirm the diagnosis of inverted papilloma [11].
• Laboratory tests: Laboratory tests, such as cytology, may be used to screen for this condition. However, cystoscopy serves as both the diagnostic procedure and definitive treatment of choice [7].

References

[4] by R Santi · 2020 · Cited by 6 — Preoperative diagnosis of IUP is difficult.

[7] by DJ Caro · 1978 · Cited by 80 — Laboratory tests and x-rays may be of value as screening modalities, but cystoscopy serves as definitive treatment as well as the diagnostic procedure of choice ...

[8] by M Takeuchi · 2015 · Cited by 12 — On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk ...

[11] A case is reported of inverted papilloma of the renal pelvis in a patient with previous transitional cell carcinoma of the bladder. The renal pelvic lesion was diagnosed and treated with a flexible ureteropyeloscope.

The differential diagnosis for renal pelvis inverted papilloma includes:

• Urothelial carcinoma: This is the most common malignant tumor of the upper urinary tract, and it can be difficult to distinguish from inverted papilloma based on histological appearance alone [7]. However, urothelial carcinomas are typically more aggressive and have a higher nuclear grade than inverted papillomas.
• Nephrogenic adenoma: This is a rare benign tumor that can mimic the appearance of inverted papilloma. However, nephrogenic adenomas tend to be more superficial and have a more complex architecture [9].
• Florid von Brunn nests and cystitis cystica: These are benign lesions that can be mistaken for inverted papilloma due to their similar histological appearance. However, florid von Brunn nests and cystitis cystica typically have larger nests of urothelial cells with regular spacing [3].
• Transitional cell carcinoma with an inverted growth pattern: This is a variant of urothelial carcinoma that can mimic the appearance of inverted papilloma. However, transitional cell carcinomas tend to be more aggressive and have a higher nuclear grade than inverted papillomas.

It's worth noting that the differential diagnosis for renal pelvis inverted papilloma can be challenging, and a thorough histological examination is often necessary to distinguish it from other lesions [7].