Spleen Pathology Overview

Spleen Pathology

• Splenomegaly Causes: Portal hypertension, infections, hematologic diseases, congestive diseases are the four major causes
• Splenomegaly Size: Spleen is considered grossly enlarged when greater than 13 cm
• Splenic Ligaments: Lienorenal, gastrosplenic, and phrenicocolic ligaments stabilize the spleen
• Normal Spleen Echogenicity: Typically isoechoic or slightly hyperechoic compared to the liver
• Splenic Cysts (80%): Pseudocysts, commonly from trauma or infarction, account for the majority
• Splenic Calcifications: Granulomatous infection is the most prevalent cause
• Splenic Trauma Findings: Hematoma, free fluid, are common findings in splenic trauma
• Splenic Trauma Symptoms: LUQ pain, left shoulder pain, dizziness, hypotension, decreased hemoglobin
• Benign Splenic Tumor: Cavernous hemangioma is the most frequent benign tumor
• Splenic Hemangioma Appearance: Heterogeneous echogenic mass with small hypoechoic areas
• Splenic Hamartoma: A rare vascular tumor related to Wiskott-Aldrich syndrome;
• Splenic Lymphoma Appearance: Hypoechoic bulky nodules
• Metastatic Cancer to Spleen: Melanoma is the most common type of metastasizing cancer to the spleen; metastatic lesions often appear as "bull's-eye" hypoechoic lesions
• Splenic Infarct: Wedge-shaped hypoechoic lesion. Common cause is occlusion of a splenic artery branch
• Splenic Abscess Appearance: Hypoechoic lesion with hyperechoic foci and debris;
• Congestive Splenomegaly Origin: Portal hypertension is the most common cause
• Granulomatous Disease Ultrasound: Bright echogenic lesions with shadowing
• Sickle Cell Anemia (Early-Stage Crisis): Enlarged spleen is a key finding
• Splenic Function: Filter old/damaged red blood cells (RBCs).
• Autosplenectomy: Spleen shrinks and slowly dies
• Cirrhosis: A major cause of portal hypertension and the leading cause of congestive splenomegaly
• **Dilated Splenic/Portal Veins:**Sonographic sign of portal hypertension
• Amyloidosis: Storage disease involving amyloid protein deposition
• Bacterial Endocarditis: Major risk factor for splenic abscesses.
• HIV/AIDS: Associated with multiple small, hypoechoic splenic lesions.
• Lymphoma: Most common primary malignancy.
• Angiosarcoma: Highly aggressive, poor prognosis vascular splenic malignancy
• Gaucher's disease: Lipid metabolism disorder causing fatty deposits & splenomegaly. Sonographically presents with multiple hypoechoic lesions. The spleen is often enlarged and hyperechoic.
• Histoplasmosis: Infection linked to bird and bat droppings; hyperechoic lesions, sometimes with shadowing.
• Subcapsular Hematoma: Intact splenic capsule characterizes this condition

Kidney Pathology

• Normal Bladder Capacity: Typically around 500 mL
• Normal Bladder Wall Thickness (Full): Approximately 3 mm
• Bladder Wall Layers (Outer to Inner): Serosa, detrusor muscle, submucosa, mucosa (transitional epithelium)
• Transitional Epithelium Function: Allows for bladder expansion
• Trigone: A triangular region formed by the two ureteral openings and the urethra
• Bladder Support Structures: Pelvic muscles and medial umbilical ligament
• Ureterovesical Junction Function: Prevents urine reflux into the ureters
• Normal Post-Void Residual Volume: Less than 10% of pre-void volume
• Normal Bladder Ultrasound Appearance: Anechoic with thin echogenic walls

Bladder Pathology

• Bladder Duplication: Complete or partial duplication of the bladder (rare)
• Bladder Exstrophy: The bladder is exposed outside the body due to anterior abdominal wall closure failure.
• Patent Urachus: Failure of the fetal urachus to close, causing urine leakage from the umbilicus
• Urachal Cyst: A cystic structure that is superior to the bladder.
• Ureterocele: A round, thin-walled cystic structure on the posterior bladder wall
• Posterior Urethral Valve Syndrome: Urethral obstruction in male infants due to a tissue flap causing bilateral hydronephrosis
• Posterior Urethral Valve Ultrasound: "Keyhole" sign (dilated urethra)
• Cystitis: Bladder wall inflammation, often from infection
• Cystitis Symptoms: Polyuria, pain, pressure, pelvic tenderness, dysuria
• Cystitis Sonographic Findings: Thickened bladder wall; may contain echogenic debris.
• Emphysematous Cystitis: Bladder infection with gas-producing bacteria; CT may show air within the bladder wall.
• Hemorrhagic Cystitis: Bladder infection with blood in the urine (echogenic debris in bladder).
• Purulent Cystitis: Bladder infection with pus in the urine
• Urinary Stasis Conditions: Bladder outlet obstruction, neoplasms, stones, pregnancy, catheterization
• Neurogenic Bladder Signs: Trabeculated, enlarged bladder with urine retention.
• Bladder Diverticulum: External herniation of the bladder wall leading to urine stasis and infection risk
• Most Common Newborn Male Bladder Outlet Obstruction: Posterior urethral valves
• Right Ureteral Obstruction Indication: Absence of a right ureteral jet on Doppler
• Urinoma: Fluid collection caused by bladder trauma
• Vesicoureteral Reflux (VUR): Backflow of urine into the ureters due to an incompetent ureterovesical junction
• Most Common Bladder Cancer: Transitional cell carcinoma (TCC)
• Primary Bladder Cancer Risk Factor: Smoking
• Bladder Cancer Symptoms: Painless hematuria, dysuria, increased urinary frequency
• Squamous Cell Carcinoma of Bladder: Rare, aggressive bladder cancer associated with chronic infection.
• Bladder Papilloma: A benign bladder tumor that could become cancerous
• Bladder Cancer Ultrasound Appearance: Irregular, solid mass
• Neurogenic Bladder Causes: Spinal cord injury, diabetes
• Urinary Tract Infection(UTI) Imaging: Can be associated with conditions like cystitis and pyelonephritis
• Uterovesical Space: Space between the uterus and bladder
• Rectovesical Pouch (Males): Space between the bladder and rectum
• Space of Retzius (Prevesical Space): Space between the bladder and pubic symphysis