What does the presence of squamous cells in the bladder indicate, and what are the next steps?

Squamous Cells in Bladder: Diagnostic Significance and Management

The presence of squamous cells in the bladder warrants thorough investigation as it may indicate squamous cell carcinoma of the bladder, which accounts for 25-81% of bladder cancers in certain populations and is associated with significant morbidity and mortality. 1

Clinical Significance of Squamous Cells in the Bladder

Potential Diagnoses

• Squamous cell carcinoma (SCC) of the bladder
• Urothelial carcinoma with squamous differentiation
• Squamous metaplasia (keratinizing or non-keratinizing)
• Contamination from non-urinary tract sources

Risk Factors

• Chronic inflammation of the bladder
• Chronic infections (particularly schistosomiasis)
• Indwelling catheters
• Bladder stones
• Neurogenic bladder dysfunction

Diagnostic Approach

Initial Evaluation

1. Office cystoscopy to directly visualize the bladder mucosa for suspicious lesions 2
2. Urine cytology to evaluate for malignant cells
3. Upper tract imaging (CT urography preferred) 2

Further Diagnostic Steps

1. Transurethral resection of bladder tumor (TURBT) with bimanual examination under anesthesia if a lesion is identified 1

   • Must include adequate sampling of muscle within the area of the tumor to assess invasion
   • Multiple biopsies may be needed for complete evaluation

2. CT scan of abdomen and pelvis if:

   • Tumor appears solid (sessile)
   • High-grade appearance
   • Suspected muscle invasion 1

Management Algorithm

If Squamous Cell Carcinoma is Confirmed:

1. Staging workup to determine extent of disease
2. Treatment based on stage:
   • Non-muscle invasive: TURBT with intravesical therapy
   • Muscle invasive: Radical cystectomy with urinary diversion
   • Metastatic disease: Systemic therapy (note that standard urothelial carcinoma chemotherapy regimens are generally ineffective for pure squamous histology) 1

If Squamous Metaplasia is Found:

1. Address underlying causes:

   • Treat chronic infections
   • Remove bladder stones if present
   • Optimize catheter management if applicable

2. Surveillance:

   • Annual cystoscopy with multiple biopsies to monitor for dysplasia 3
   • Regular urine cytology

Special Considerations

Schistosomiasis Connection

In patients with history of travel to endemic areas (particularly Africa), consider schistosomiasis as a potential cause. S. haematobium infection has been linked to squamous cell carcinoma of the bladder 1

Atypical Squamous Cells in Urine

The presence of atypical squamous cells in urine cytology is rare (0.3% in one series) but clinically significant, with 31% of cases later diagnosed with squamous cell carcinoma 4

Pitfalls and Caveats

1. Female patients: Squamous cells may represent normal anatomical variants on the trigone due to hormonal changes or contamination from the gynecologic tract 5

2. Diagnostic confusion: Abnormal squamous cells in urine may originate from:

   • Bladder malignancy
   • Urethral lesions
   • Gynecologic tract malignancies (in women)
   • Non-malignant inflammatory conditions 6

3. Surveillance limitations: Cystoscopy and cytology are poor screening tests for bladder cancer in patients with neurogenic lower urinary tract dysfunction 1

4. Histologic sampling: Multiple biopsies may be needed to rule out malignancy in areas of squamous metaplasia

The finding of squamous cells in the bladder requires thorough evaluation to rule out malignancy and identify any underlying causes. Early diagnosis and appropriate management are essential to reduce morbidity and mortality associated with squamous cell carcinoma of the bladder.