Pediatric Cystic Renal Lesions

• Autosomal Recessive Polycystic Kidney Disease (ARKD)
• Multicystic Dysplastic Kidney (MCDK)
• Multilocular Cystic Nephroma (MLCN)

Cystic Intraaxial Supratentorial Brain Lesions

• astrocytoma
• ganglioglioma and ganglioneuroma
• pleomorphic xanthoastrocytoma
• DNET
• sinus mucocele that invaded through cranium
• congenital

Cystic Extraaxial Brain Lesions

• arachnoid cyst
  • CSF filled/signal
  • middle cranial fossa (MC) > cerebral convexities, basal cisterns, retrocerebellar region
  • hypogenesis of adjacent brain
  • no enhancement
  • low on DWI (like ventricle)
• epidermoid cyst
  • has internal matrix, seen in T1
  • hyperintense to CSF on FLAIR
  • high on DWI (restricted diffusion)

read more

Congenital Cystic Adenomatoid Malformation

• Type 1
  • big cysts (2-10 cm)
• Type 2
  • multiple small cysts
  • renal and cardiac anomalies
• Type 3
  • solid

• any lobe
• alveoli replaced by adenomatoid
• surgical resection
• 70% present during 1st week of life
• 10% diagnosed after 1st year
• supplied by pulmonary artery; systemic supply rare
• can involve entire lobe
• prenatal diagnosis
  • polyhydramnios
  • fetal hydrops
  • solid or cystic mass in fetal thorax
• excise affected lobe

read more

Cystic Pediatric Neck Masses

Congenital:

• Thyroglossal duct cyst – base of tongue, hyoid
• 1st Brachial anomalies – between ear and mandible
• 2nd brachial anomalies – mc, type 2 remnant of sinus of His, post to submandibular gland, anterior to scm, AL to vessels, brachiosaurus- otorenal syndrome
• 3rd brachial anomalies – posterior or anterior triangle, cervical thymic cyst extend to mediastinum
• 4th brachial anomalies – pyriform sinus fistula, inflammation next to thyroid
• DermoId cysts – midline, paramidline, orbit, oral, nasal
• Vascular – lymphatovenous malformations, locular, FFlevels

Acquired:

• Suppuratibe adenopathy/abscess
• Necrotic mets

Thin Walled Lung Cysts

• Eosinophilic granuloma
• Lymphangioleiomyomatosis (LAM)
  • upper
  • uniform size
  • women in reproductive years
  • can rupture –> pneumothorax
• Tuberous sclerosis
• Neurofibromatosis
• LIP

histiocytosis X

• peribronchiolar distribution
• nodules become cysts
• ~ smoking
• upper lobes
• CPA spared

cystic lung disease

Pericardial Cyst

• fluid filled cardiophrenic angle mass
• R>L
• attached to parietal pericardium; do not communicate with pericardial space

Choledocal cyst

• congenital focal or diffuse dilation of bile ducts
• females
• 5 categories
  • type 1 cysts
    • 80-90%
    • saccular or fusiform
  • type 2
    • diverticula of duct
  • type 3
    • choledochoceles
    • dilation of terminal, intraduodenal portion of CBD
  • type 4
    • intrahepatic and extrahepatic cysts
  • type 5 = Caroli’s disease
    • multiple cystic dilations of the intrahepatic bile ducts
    • ~ medullary sponge kidney, AR PCKD
    • complications: liver abscess, portal vein thrombosis, biliary cirrhosis with portal hypertension
    • 100% risk of cholangiocarcinoma
    • MRCP, cholangiography, ERCP shows biliary origins of cysts
• marked biliary stasis: get infection, inflammation, stone disease
• risk of cholangiocarcinoma with age
• in neonates, disorder ~ extrahepatic biliary atresia
• Rx: surgical resection (Kasai procedure: portoenterostomy)

Cystic Fibrosis

• upper lobe predominance
• bronchiectesis = bronchial wall thickening and cysts
• tubular opacitities = mucoid impaction
• hyperinflation
• recurrent foci of consolidation
• autosomal recessive; abnormal secretion from exocrine glands (airway, pancreas, LB, salivary and sweat glands)
• chronic pulmonary disease, pancreatic insufficiency
• most diagnosed at infancy and childhood; milder forms diagnosed as adults
• confirmed with sweat test or molecular biologic testing (PCR)

Hemangioblastoma

• benign
• most common primary cerebellar neoplasm in adults
• multiple vs solitary
• multiple, supratentorial ~ von Hippel-Lindau disease
• spinal cord, medulla, cerebral hemispheres
• always superficial location; pia matter blood supply
• CT = well-defined cystic lesion, intensely enhances; 40% solid nonspecific findings; rarely calcify
• MRI = low T1, high T2, enhances, flow voids
• DDx: posterior fossa tumors
• Link

Liver Infections

Pyogenic Abscess

• seeding from appendicitis, diverticulitis, cholecystitis, cholangitis, endocarditis
• complex fluid collections
• pic

Fungal Abscess

• immunocompromised patients
• Candida
• “wheel within a wheel” appearance, target lesion
• pic

Granulomatous Disease

• Pneumocystits carinii in AIDS patients, MAI, CMV
• multiple echogenic foci throughout the liver

Parasite

• Echinococcal hydatid cyst
• Amebic
• Schistosomiasis
• variable cystic appearances, daughter cysts, calcifications
• pic

Cystic Neck Masses in Pediatrics

1. Brachial Cleft Cyst: Type 2 most common (1-4)
2. Ranula: impacted salivary gland
3. Thyroglossal Duct Cyst: abarrent migration of thyroid tissue from tongue
4. Venolymphatic Malformation: Fluid fluid levels, posterior to SCM
5. Odontogenic Keratocyst: associated with teeth

Simple Bone Cyst

• unicameral bone cyst; simple bone cyst
• fluid-filled cavity
• fallen fragment sign: detached fragment of bone in dependent portion of cyst
• males:females 2:1
• calcaneus, long bones (esp children)
• lucent, well-demarcated, geographic
• long axis parallel to long bone
• broader toward metaphysis than diaphysis
• pathological fractures

Bosniak CT Classification of Cystic Masses

I = simple cyst; nonoperative

II = septated, minimal calcium, nonenhancing high-density cysts, infected cysts; nonoperative

III = multiloculated, hemorrhagic, dense calcification, non-enhancing solid component; renal-sparing component

IV = marginal irregularity, enhancing solid component; Radical nephrectomy

Thin Walled Cysts in the chest

• Eosinophilic granuloma
• Lymphangioleiomyomatosis
• Tuberous sclerosis
  
• Neurofibromatosis

Cystic Pancreatic Masses

• Pseudocyst (MC)
• True Cyst
• Lymphoepithelial Cyst
• Peripancreatic cyst
• Serous Cystadenoma
• Solid tumor with cystic change
• Mucinous Cystic Neoplasm
• Intraductal Papillary Mucinous Neoplasm
• Papillary and Solid Epithelial Neoplasm (pseudopapillary tumor of the pancreas)

Cystic Liver Masses

• Simple cyst
• Polycystic Liver
• Bile Duct hamartoma
• Caroli Disease
• Sarcoma, undifferentiated embryonal
• Biliary cystadenoma
• Neoplasm: cystadenocarcinoma, biliary cystadenoma
• Mets, cystic
• Abscess
• Hydadit cyst
• Extrapancreatitic pseudocyst (pancreatitis)
• Hematoma
• Biloma

Cystic Kidney Masses

• Polycystic kidney disease
• Simple Renal cysts
• Von Hippel Lindau disease
• tuberous sclerosis
• Uremic Cystic Kidney Disease (acquired vs medullary)
• Medullary Sponge Kidney
• Multicystic dysplastic Kidney
• Infection: TB, echinococcus, abscess
• Cystic degeneration of renal tumor