Cystic Lung Disease in Children Spectrum of Multidetector CT Findings

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					Cystic Lung Disease in Children:
 Spectrum of Multidetector CT

 JH Kim, GW Park, YN Kim, SY Yoo, H E
        Samsung Medical Center,
Sungkyunkwan University School of Medicine
   Pediatric Pulmonary Cysts

• Congenital cystic lung diseases
• Abscess or cavitary infections
• Chronic stage of interstitial lung
• Cystic neoplasms
• Others
    Congenital Cystic Lung Diseases

•   CCAM
•   Sequestration
•   Intrapulmonary bronchogenic cyst
•   Congenital lobar overinflation (CLO)
•   Cysts in hypoplastic lung associated
    with absent pulmonary artery (PA) or
    vein (PV)
     Congenital Cystic Adenomatoid
        Malformation (CCAM)
• Congenital lung mass of adenomatoid proliferation
• Supplied by PA, communicating with tracheo-bronchial tree
• Classified into type 1-3, according to size /lining epithelium
• Progressive mediastinal shift /hydrops fetalis prenatally
• Mostly confined to a single lobe
• CT should be performed for surgical planning, to identify
  those lesions detected in utero, but not evident on plain
  radiograph, and to exclude systemic arterial supply.
          Neonate with CCAM
             The retained fetal
             fluid within the cysts
             is progressively
             replaced by air and
             large lesions cause
             mass effect.

Initial                               6 months later
Type 1 CCAM

  Type I CCAM contains one or more
  large cysts, and is the most common
  type (up to 70%). The cyst is lined by
  bronchial (ciliated columnar)
                       Type 2 CCAM

Type II CCAM contains numerous small cysts of uniform size, occurs in
20–40% of cases, and may be found in association with other congenital
lesions including sequestration. In this patient, a gastric duplication cyst
(arrow) is associated. The cysts are lined by bronchiolar epithelium.
Pathological Features of CCAM
               • Multiple thin walled
               • Consolidation with
                 : Glandular /
                 bronchiolar structure
               • Low attenuation
                 : Microcysts blend
                 with normal lung
                     - Kim WS et al. AJR 1997
• Aberrant lung tissue that does not connect to the
  bronchial tree/pulmonary artery (PA), retaining
  systemic arterial connection

• Venous drainage is primarily to the systemic veins in
  extralobar (ELPS), and pulmonary veins (PV) in
  intralobar (ILPS). ELPS usually presents in the neonate,
  and associated congenital anomalies are common (50%).

• May contain cysts if infected or if a communication with
  the foregut or an association with CCAM exist.

• Typical location is in the lower lobes. ELPS can be
  found in the mediastinum or below the diaphragm.
               Intralobar Sequestration

ILPS is commonly
diagnosed in elder
children with recurrent
Multiple cystic lesions
are seen in these 10 and
8-year-old girls raising
suspicion of combined
Note aberrant arteries
(arrow) from the aorta.
Bronchogenic Cyst

             Supernumerary budding
             from foregut containing
             cartialge and lined by
             ciliated columnar
             Mediastinal> subcarinal>
             perihilar > intrapulmonary
             Blood supply from PA
             Similar to type 1 CCAM
    Cysts associated with absent PA

A                       B                        C

Proximal interruption of PA (B, arrow), opposite to the aortic arch
Affected lung is absent or hypoplastic, may associated with cysts (C)
Blood supply from PDA, bronchial, transpleural collaterals
Pulmonary HT, hemoptysis, infection, congenital heart disease
        Pulmonary cysts with absent PV

• Usually Right, at the venoatrial junction
• Associated with congenital heart disease
• Decreased lung volume, edema, effusion, air cysts

A               B                   C                          D
In addition to the pulmonary cysts (arrows in A, B) with absent RPV (arrow in C),
there are ectopic liver (L in A), dextrocardia (C, D), and hypoplastic right lung
with pneumonia.
      Congenital Lobar Overinflation
• Progressive overinflation of upper lobe or middle lobe after
• Defective bronchial / alveolar wall or obstruction of

There are numerous cysts in the hyperinflated right lung raising suspicion of
CCAM though pathological examination after resection revealed CLO.
           Cystic Lesions
      Associated with Infection

•   Abscess
•   Necrotizing pneumonia
•   Endobronchial tuberculosis
•   Fungal infection
•   Post-infectious pneumatocele
  Thick walled cysts with fluid level
 • Infected cysts exhibit thick wall and contain air
   when communication occurs with bronchus.

 A                   B                     C
Abscess (A), infected CCAM (B), and large cavitary tuberculosis in
a patient with severe combined immune deficiency patients (C) were
confirmed by pathological examination.
        Endobronchial Tuberculosis (TB)
   • Important morbidity in immune compromised patients
   • Consolidation, cavitation, air space nodules are reflecting
     endobronchial spread active TB.

    A                         B                     C
There are irregular thick-walled cavities in the posterior segment of RUL in 3
different patients (A-C). Scattered poorly defined nodules are seen which are
peribronchial in location (B). Focal consolidation is surrounding the cavities.
          in Patients with Leukemia

  A                        B

• Patients who underwent chemotherapy and BMT presenting
  respiratory symptoms and nodules or consolidations with halo
  sign at HRCT scan suggest invasive aspergillosis.

• Cavitations may be seen in air-space consolidations or large
         Cystic Neoplasms
• Pulmonary blastoma from CCAM
• Congenital pulmonary myofibroblastic
  tumor (CPMT)
• Multicystic mesothelioma
• Mesenchymal hamartoma
• Congenital pulmonary
  myofibroblastic tumor
• Cystic metastasis
Pleuropulmonary blastoma
          • Rare aggressive
            dysontogenic neoplasm
            affecting children.
          • Increasing malignancy from
            type1 (cystic) through type2
            (solid and cystic) to type 3
          • May occur within the pre-
            exsiting congenital cystic
            lung lesion.

            - Orazi C, et al. Pediatr Radiol 2007
            Unusual Congenital Pulmonary
            Myofibroblastic Tumor (CPMT)
   • Only about 25 cases are reported (= Congenital mesenchymal tumor/
     leiomyosarcoma /bronchopulmonary fibrosarcoma)
   • Large solid mass in a very young infants, perinatal hydrops /death
   • Usually resected with long-term survival
   • May mimic a sarcoma due to the high mitotic rate / cellularity

      A                     B                      C
Multiseptated cystic mass (B) became enlarged (C) over 2 months and was
presumed to be pleuropulmonary blastoma, which was confirmed to be CPMT
      Multicystic Mesothelioma

  A                        B                 C

Cheat radiogram (A) shows cystic lesion in the right parahilar
area (arrow). There are multiple thin walled cysts with
septation on CT scans (B, C). The cysts tend to be peripheral in
location. Resection was performed under the impression of
CCAM and histologically confirmed to be a benign multicystic
                Cystic metastasis
• Cystic or cavitary metastasis has rarely been reported
  associated with various sarcomas and bladder carcinoma.
• Thin-walled cavitary lesions can easily be missed on plain

  A           B               C              E
              There are multiple thin walled cysts on HRCT scan
              in a patient with epithelioid sarcoma in the right calf
              muscle (D). Subpleural cysts caused pneumothorax
              (E, arrows).
• Rare disorder affecting the lymphatic channels from
  mediastinum to pleura, usually in children /young adults
• Frequently ends with death due to progressive course
• Mediastinal soft tissue / thickening of peribroncovascular
  bundles and interlobular septae/ cysts

There are numerous cysts with air-fluid levels, thickening of the interlobular septa
and bronchovascular bundles. Multiple cysts are also seen in the retrocaval area,
peritoneal space, and the spleen.
      Cysts Associated with
     Interstitial Lung Disease
•   Acute interstitial pneumonia
•   Hypersensitivity pneumonitis
•   Heiner syndrome
•   Nonspecific interstitial pneumonia
•   Chronic pneumonitis of infant
•   Pulmonary Langerhans cell histiocytosis
           Acute Interstitial Pneumonia
• Rapidly progressive disorder of unknown etiology
• Diffuse alveolar damage, acute onset , extremely ill, rapid
  progression to respiratory failure
• Mortality > 50%
• Recurrent episodes or interstitial fibrosis with honeycombing
• Bilateral, symmetrical, lower zone, dependant portion

                                                 Multiple cystic lesions
                                                 are seen suggesting
                                                 traction bronchiectasis
                                                 or PIE. In addition,
                                                 there are ground glass
                                                 opacities, multifocal
                                                 patchy subpleural
                                                 consolidations, and
                                                 pneumomediastinum on
            Hypersensitivity Pneumonitis
• Immune-mediated ILD, Acute/subacute/chronic forms
• Confirmed by lymphocytosis in BAL, antibody in serum, biopsy
• Ill-defined centrilobular nodules, mainly upper & middle lung zones,
  GGO (patchy distribution), mosaic perfusion
• Cysts may be seen in chronic disease as honeycombing, traction
  bronchiectasis, or emphysema

A                                   BC            C
HRCT demonstrate numerous cystic lesions, extensive nodular and ground
glass opacity (GGO) and bilaterally. There are bronchial dilatation and
thickening suggesting fibrosis. The cysts remains while GGO and nodular
opacities improved on follow-up images (B).
                      Heiner Syndrome
• Food (cow’s milk) hypersensitivity pulmonary disease
• Chronic cough, dyspnea, recurrent pneumonia, anemia, hemoptysis
• Improvement after milk avoidance + antibody to cow’s milk
• Pulmonary hemosiderosis in severe case

    A                                     B
  Initial CT (A) shows bilateral patchy infiltrates with GGO and follow-up
  CT after 16 M reveals small cysts (arrows) suggesting chronic disease
  with fibrosis (Courtesy of Woo Sun Kim)
       Nonspecific Interstitial Pneumonia
• Histological types; Cellular / Fibrotic ( worse Px) NSIP
• Idiopathic / Collagen vascular disease / Drug, radiation toxicity
• Share common CT finding with DIP, LIP in children

   A                                  B
  HRCT scans show GGO, traction bronciectasis, septal thickening which
  is bilateral lower lung predominant pattern (A). There are numerous
  subpleural/peribronchial cysts and emphysematous change in B.
            Chronic Pneumonitis of Infancy

   • Recently described distinct form of interstitial lung disease
   • Increasing respiratory failure in first few months of life
   • High mortality rate in spite of high dose steroids,
     immunosuppressive drug, and lung transplantation

 A                             B                         C
Initial CT (A) shows widespread GGO and reticular change. Multiple small
   cysts and interlobular septal thickening are seen on follow-up CT (B, C)
   obtained 3 months later.
    Pulmonary Langerhans Cell Histiocytosis (PLCH)

• Childhood PLCH; < 10% of LCH, (usually multisystem
  LCH with 20% mortality)
• Diagnosed by biopsy
• Treated with steroid /chemotherapy

                                   HRCT scans of 3
                                   different children with
                                   PLCH show multiple
                                   cysts. GGO, nodules,
                                   and     fine   reticular
                                   opacities (A, B) are
                                   also seen in the lung,
                                   which are bilateral in
A          B          C            distribution.

• Post-traumatic / post-infectious
• Pulmonary interstitial emphysema
• Bronchiectasis
         Post-traumatic Pneumatocele
• Following blunt chest trauma & pulmonary contusion
• Parenchymal tear from sudden elastic recoil after rapid compression
• More common in children due to better elastic recoil of thorax
• Occurs 12-24 H after trauma, though it appears 24-72 H later, after
  resorption of pulmonary contusion
• Resolusion within 2-16 W

                                                    Initial chest PA (A)
                                                    shows patch opacity
                                                    representing pulmonary
                                                    contusion. Thick-walled
                                                    cyst with air-fluid level
                                                    (arrow) appears after 3
                                                    days (B, C). Note
                                                    another small cysts
                                                    (arrowheads in C) in
    A              B              C                 the RLL.
Pulmonary Interstitial Emphysema (PIE)


A                   B
                PIE (arrows) is seen in patients with
                horseshoe lung (A) and dermatomyositis
                (B). Note isthmic lung (I) in A, and GGO
                and small subpleural cysts suggesting
                pulmonary involvement of dermatomyositis
                in B. Sometimes cystic PIE mimics CCAM
                (C). Dot or tubular opacity (arrows in C)
 C              representing bronchovascular bundles are
                helpful clue for diagnosis of PIE on CT.
Childhood bronchiectasis may occur associated with cystic
fibrosis (A) and Katargener’s syndrome (B).

         A                      B

                                       In this patient with an
                                       inflammatory pseudotumor
                                       (arrow in C) bronchiectasis
                                       in the collapsed lung (arrow
                                       in D, E) is seen which is
C            D              E          distal to the mass.

• A wide spectrum of congenital or acquired
  diseases may be associated with cystic
  lesions in the pediatric lung.
• MDCT permits better characterization of
  cystic lesions and facilitates the evaluation
  of extent and distribution of the lesions.