Definition/General
Introduction:
Lithiasis-related changes in urine cytology represent mechanical trauma and inflammatory responses due to urinary stone disease
These changes result from crystal deposition and stone passage
Reactive cellular changes are commonly observed
Recognition helps correlate with clinical stone disease.
Origin:
Changes originate from mechanical irritation by crystals and stones
Urothelial trauma occurs during stone passage
Chronic inflammation develops around stones
Crystal deposition causes direct cellular injury
Secondary bacterial infections may occur.
Classification:
Classified by crystal type and location
Calcium oxalate stones (most common)
Uric acid stones
Calcium phosphate stones
Struvite (magnesium ammonium phosphate)
Cystine stones (rare)
Drug-related crystals.
Epidemiology:
Affects 10-12% of population lifetime
More common in males (3:1 ratio)
Peak incidence 20-50 years
Higher prevalence in hot climates
Recurrence rate 50% within 5 years
Associated with dietary factors
Genetic predisposition in some cases.
Clinical Features
Presentation:
Renal colic (severe flank pain)
Hematuria (microscopic or gross)
Dysuria and urinary frequency
Nausea and vomiting
Suprapubic pain
Radiating pain to groin
Oliguria or anuria (obstruction).
Symptoms:
Colicky pain (waves of severe pain)
Hematuria (blood in urine)
Urinary urgency and frequency
Burning sensation during urination
Restlessness during pain episodes
Fever (if infection present)
Cloudy or foul-smelling urine.
Risk Factors:
Dehydration (insufficient fluid intake)
Diet high in oxalates (spinach, nuts)
High sodium intake
Excessive animal protein
Family history of stones
Certain medications
Metabolic disorders
Anatomical abnormalities.
Screening:
Urinalysis with microscopy for crystals
24-hour urine collection for metabolites
Imaging studies (ultrasound, CT)
Stone analysis when passed
Serum chemistry panel
Urine culture to exclude infection.
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Gross Description
Appearance:
Hematuria ranging from pink to red
May contain visible crystals
Cloudy appearance due to crystalluria
Sediment visible on standing
Normal color between stone passage episodes
May show proteinuria.
Characteristics:
Crystal deposits visible in sediment
Increased specific gravity
pH varies with crystal type
Protein and blood positive
Cellular debris may be present
Bacterial contamination possible.
Microscopic Description
Immunohistochemistry
Positive Markers:
CK7 and CK20 (urothelial cells)
Uroplakin (umbrella cells)
p53 (wild-type pattern in reactive cells)
Ki-67 (increased proliferation)
CK5/6 (basal cells)
Cytokeratin AE1/AE3.
Negative Markers:
p16 (usually negative)
High-risk HPV markers
CEA (negative)
CA 19-9 (negative)
TTF-1 (negative)
PSA (negative)
Vimentin (negative in epithelial cells).
Diagnostic Utility:
Limited utility in lithiasis diagnosis
Confirms urothelial origin
Excludes malignancy
p53 shows reactive (not mutant) pattern
Ki-67 elevation expected in reactive states
Clinical correlation more important.
Molecular/Genetic
Differential Diagnosis
Similar Entities:
Urothelial dysplasia
Infectious cystitis
Radiation cystitis
Drug-induced cystitis
Malignancy
Instrumentation trauma.
Distinguishing Features:
Lithiasis: Crystals present, clinical stone disease
Dysplasia: Monotonous cells, high N:C ratio
Infection: Organisms present, inflammatory background
Radiation: Bizarre cells, history of radiation
Malignancy: Severe atypia, irregular chromatin.
Diagnostic Challenges:
Severe reactive changes may mimic dysplasia
Chronic inflammation can be marked
Crystal artifacts vs pathological crystals
Secondary infection complicates picture
Instrumentation effects similar.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
Urine specimen, [collection method], [volume] ml
Specimen Adequacy
Adequate for cytological evaluation
Crystals
[type] crystals identified: [morphology and quantity]
Cellular Findings
Reactive urothelial changes with [specific features]
Background
[degree] inflammatory background with [components]
Diagnosis
Crystalluria with reactive changes, consistent with lithiasis
Clinical Correlation
Correlate with imaging findings and clinical stone disease
Recommendations
Stone analysis when available. Metabolic evaluation. Dietary counseling.