bladder flat intraepithelial lesion

A flat intraepithelial lesion of the urinary bladder refers to a type of abnormal growth that occurs on the surface of the bladder lining, but does not form a papillary (finger-like) projection into the bladder lumen. This type of lesion is often classified as urothelial dysplasia or carcinoma in situ (CIS), which are considered preneoplastic or early cancerous changes.

According to the World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification system, flat intraepithelial lesions of the urinary bladder can be categorized into several subtypes, including:

• Reactive atypia: a non-neoplastic condition characterized by mild cellular abnormalities
• Atypia of unknown significance: a condition where the cellular changes are not clearly benign or malignant
• Dysplasia (low-grade intraepithelial neoplasia): a preneoplastic lesion with moderate cellular abnormalities
• Carcinoma in situ (high-grade intraepithelial neoplasia): a high-grade preneoplastic lesion with significant cytologic atypia

These flat lesions can be difficult to diagnose and may require careful histological examination, as well as molecular and immunohistologic analyses, to differentiate them from other types of bladder lesions.

References:

• The WHO/ISUP consensus classification system for bladder neoplasms (1998) [11]
• The definition of flat intraepithelial lesions of the urinary bladder by the American Journal of Clinical Pathology (2012) [14]
• The molecular and immunohistologic analyses of flat intraepithelial lesions of the urinary bladder by the American Journal of Clinical Pathology (2010) [15]

Understanding Flat Intraepithelial Lesions of the Urinary Bladder

Flat intraepithelial lesions (FILs) of the urinary bladder are abnormal changes in the cells lining the bladder. These changes can be a sign of an underlying condition, such as cancer.

Symptoms and Warning Signs

• Frequent and urgent need to pass urine
• Pain when passing urine
• Pain in the lower abdomen or back
• Blood in the urine (pee) [4][6]

It's essential to talk to a healthcare provider if you experience any of these symptoms, as they can be indicative of an underlying issue.

Clinical Outcomes and Diagnosis

The World Health Organization/International Society of Urological Pathology consensus classification system categorizes FILs into reactive atypia, atypia of unknown significance, dysplasia, and carcinoma in situ. A healthcare provider will assess the severity of the condition based on these categories [1][2].

Prevention and Early Detection

While there is no guaranteed way to prevent FILs, early detection can significantly improve treatment outcomes. Regular check-ups with a healthcare provider can help identify any abnormalities in the bladder cells.

Risk Factors and Complications

FILs have a high risk of becoming invasive, and sometimes they can be a sign that there's an invasive cancer nearby [8]. In advanced cases, symptoms may include pelvic or bony pain, lower-extremity edema, or flank pain. A palpable mass on physical examination is rare in these cases but can occur [9].

Grading and Staging

It has been proposed that bladder intraepithelial lesions be graded based on the level of involvement of atypical cells (i.e., mild dysplasia for lesions showing atypia confined to the lower one third, moderate dysplasia for lesions showing atypia in more than half of the epithelium) [10].

References

[1] Amin MB, McKenney JK Adv Anat Pathol 2002 Jul;9(4):222-32. doi: 10.1097/00125480-200207000-00002. [2] by GP Paner · 2022 · Cited by 5 — An approach to the diagnosis of flat intraepithelial lesions of the urinary bladder using the World Health Organization/ International Society of Urological Pathology consensus classification system. [3] by GP Paner · 2022 · Cited by 5 — Understanding Flat Intraepithelial Lesions of the Urinary Bladder. [4] Symptoms and Warning Signs. [5] Clinical Outcomes and Diagnosis. [6] Blood in the urine (pee). [7] Prevention and Early Detection. [8] Risk Factors and Complications. [9] Pelvic or bony pain, lower-extremity edema, or flank pain. [10] Grading and Staging.

Diagnostic Approaches for Bladder Flat Intraepithelial Lesions

Bladder flat intraepithelial lesions are a type of abnormal cell growth in the urinary bladder that can be challenging to diagnose. Various diagnostic tests and approaches have been proposed to identify these lesions accurately.

• Cystoscopy: This is a standard diagnostic method for evaluating the bladder, including flat intraepithelial lesions (1). Cystoscopy involves inserting a cystoscope into the bladder through the urethra to visualize the bladder lining.
• Photodynamic Diagnosis (PDD) Cystoscopy with Fluorescence: PDD cystoscopy is a highly sensitive method for detecting flat lesions, including intraepithelial neoplasias (7). This technique uses fluorescent dyes to highlight abnormal cells.
• Molecular and Immunohistologic Analyses: While these analyses can provide valuable information, they are not always reliable in solving diagnostic variations of flat intraepithelial lesions (2, 5).
• Urologic Pathology (WHO/ISUP) Classification System: This system categorizes bladder neoplasms, including flat intraepithelial lesions, into distinct categories based on histological and cytological findings (6).

Challenges in Diagnosis

The diagnosis of flat intraepithelial lesions can be challenging due to the lack of supportive ancillary testing. Commonly used immunostains for supporting the diagnosis of Carcinoma In Situ (CIS), such as CK20, CD44, and p53, are not always reliable (9).

Recent Advances

Recent studies have proposed new diagnostic approaches based on cytologic and histologic findings. For example, a study by Murata et al. in 2010 proposed diagnostic approaches for flat intraepithelial lesions defined by the WHO classification (8). Another study by Nishikawa et al. in 2022 significantly improved the classification accuracy of images of flat urothelial lesions using a machine learning-based approach (10).

In conclusion, various diagnostic tests and approaches are available for evaluating bladder flat intraepithelial lesions. While cystoscopy and PDD cystoscopy with fluorescence are highly effective methods, molecular and immunohistologic analyses may not always provide reliable results.

References:

1. by L Cheng · 2000 · Cited by 134
2. by GP Paner · 2022 · Cited by 5
3. An approach to the diagnosis of flat intraepithelial lesions of the urinary bladder using the World Health Organization/ International Society of Urological ...
4. by S SHARMA · 2009 · Cited by 135
5. by GP Paner · 2022 · Cited by 5
6. by L Cheng · 2000 · Cited by 134
7. One of the best methods is PDD (photodynamic diagnosis) cystoscopy with fluorescence, which allows to recognition of (flat) lesions.
8. by S Murata · 2010 · Cited by 33
9. by GP Paner · 2022 · Cited by 5
10. by T Nishikawa · 2022 · Cited by 5

The differential diagnosis of bladder flat intraepithelial lesions can be quite challenging, as they can mimic various other conditions. Here are some key points to consider:

• Reactive atypia: This is a common condition that can present with flat lesions in the bladder. It is often associated with inflammation or irritation of the urothelium (the lining of the bladder) [1].
• Atypia of unknown significance: This term refers to flat lesions that do not fit into any other category, but are still considered to be abnormal [2].
• Dysplasia (low-grade intraepithelial neoplasia): This is a pre-cancerous condition characterized by flat lesions in the bladder. It can progress to more severe forms of cancer if left untreated [3].
• Carcinoma in situ (high-grade intraepithelial neoplasia): This is a high-grade pre-cancerous condition that can also present with flat lesions in the bladder. It has a high risk of progressing to invasive cancer [4].

In addition to these conditions, other differential diagnoses for flat bladder lesions include:

• Hyperplastic, metaplastic, inflammatory, infectious, and reactive lesions: These types of lesions can mimic cancer and require tissue sampling and histologic assessment for definitive diagnosis [5].
• Papillary transitional cell carcinoma: This is a type of cancer that can present with papillary or polypoid growths in the bladder. It requires careful differentiation from flat cystitis, which can be challenging [6].

To accurately diagnose flat intraepithelial lesions of the urinary bladder, it is essential to consider the clinical history, cystoscopic findings, and histologic features. The World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification system provides a useful framework for categorizing these lesions [7].

References:

[1] Context result 6 [2] Context result 11 [3] Context result 5 [4] Context result 11 [5] Context result 8 [6] Context result 9 [7] Context result 12