Case Report

Submitted by: John Knight, MS4

Faculty reviewer: Sandra Oldham, MD

Date accepted: August 27, 2014

Radiological Category: Principal Modality (1):

Principal Modality (2):

Pediatrics

CXR

CT

Case History

• The patient is a two-week old female born at 34 weeks 6 days gestation who presents for follow-up of a cystic lesion noted in the right lung on prenatal ultrasound.

Birth History:

• Delivered 34+6 weeks via primary C/S secondary to pregnancy-induced hypertension

• APGARs 8 & 9• Twin Gestation• Pregnancy also complicated by: well-controlled gestational Diabetes Mellitus,

twin to twin transfusion syndrome• Status-post laser ablation of placental anastamosis at 21 weeks

Case History

• Birth itself uncomplicated• Patient and twin admitted to NICU due to prematurity• Hemodynamically stable• No labored breathing, oxygen desaturation, or clinical signs of hypoxia• Patient spent 16 days in the NICU prior to discharge to home

Chest X-Ray, Day of Life 1

Chest CT with Contrast, Day of Life 14

Chest CT with Contrast, Day of Life 14

Chest CT with Contrast, Day of Life 14

Chest CT with Contrast, Day of Life 14

Chest CT with Contrast, Day of Life 14

Chest CT with Contrast, Day of Life 14

• Intrapulmonary bronchogenic cysts

• Pleuropulmonary Blastoma

• Congenital Pulmonary Airway Malformation, Type I

• Congenital Pulmonary Airway Malformation, Type II

• Congenital Lobar Overinflation

Which one of the following is your choice for the appropriate diagnosis?

Test Your Diagnosis

Multiple hyperlucent foci within the right upper lobe, with the largest measuring 1.3 x 1.1 x 1.2 cm.

No cystic lesions are noted in the right middle and lower lobes, or the left lung.

The heart size, mediastinal structures, and abdomen are within normal limits

• CPAM Type I

• CPAM Type II

• Pleuropulmonary Blastoma

Findings:

Differential:

Findings and Differentials

•CPAM Type I– Characterized by large intercommunicating air-filled cysts (>2 cm) surrounded by multiple smaller cysts

– Lined by bronchial-type epithelium without cartilage

– Communicate with surrounding lung; may see air-fluid levels within cysts

– Most common type of CPAM (60 – 70% of cases)

– Diagnosis often made with prenatal ultrasound

•CPAM Type II– Characterized by mixture of solid tissue and small air-filled cysts (<2 cm)

– Consistent with the small, hyperlucent foci noted on the patient’s CT

– 15 – 20% of all cases

– 60% of cases associated with other congenital anomalies

Discussion: Differential Diagnosis

• Pleuropulmonary Blastoma– Relatively rare malignancy of the lung

– Typically diagnosed in first 4 years of life

– Often radiographically indistinguishable from CPAM Type IV and Type I

– Histology key to differentiating from CPAM

– Pathology in our patient showed pulmonary parenchyma with cysts lined by ciliated epithelium

– Inconsistent with PPB, which is composed of malignant mesenchymal cells

Discussion: Differential Diagnosis

Congenital Pulmonary Airway Malformation Type II

Diagnosis

• History– First described in 1949 by Ch’in and Tang

– Classification system developed in 1977 by Stocker, which he expanded in 2001

– Also known as Congenital Cystic Adenomatoid Malformation prior to these changes

• Epidemiology– 1 in 8,300 – 35,000 live births

• Pathophysiology– Failure of normal broncho-alveolar development

– Possibly triggered by in utero airway obstruction, atresia

– Results in hamartomatous proliferation of terminal respiratory units in a gland-like, “adenomatoid” pattern

– Lack of normal alveolar development in affected region

–Five different patterns seen clinically

Congenital Pulmonary Airway Malformation

• Type 0– < 3% cases

– No cysts, or very small ones

– Usually involves entire lung

– Incompatible with life

• Type I• Type II• Type III

– Solid adenomatoid malformation with minor cystic components

– 5 – 10% of cases

• Type IV– Large cysts up to 10 cm

– 10 – 15% of cases

– Difficult to distinguish from Type I CPAM, PPB

– Increasing evidence that all or most Type IV CPAM cases might be PPB

Congenital Pulmonary Airway Malformation

• Prenatal– Ultrasound: microcystic lesions appearing echogenic and solid. Relatively sensitive.

– MRI: equally sensitive and more specific

– Lesions will often stabilize or regress prior to birth

• Asymptomatic neonates– If prenatal diagnosis made, patient should have CXR in neonatal period

– CXR may be normal in up to 40% of cases

– Follow-up CT chest at 4 – 6 weeks of age to confirm and evaluate lesion

– CT more sensitive than CXR

• Postnatal Diagnosis– Typically made with CXR

– CT also useful

Imaging Options

• Clinical course– Typically diagnosed on prenatal ultrasound

– Presentation after birth variable; depends on size of the lesion

– Large lesions may cause pulmonary hypoplasia and progressive pulmonary distress in the neonatal period resulting in death without intervention

– Small lesions, if not caught on imaging, may cause no symptoms and go undiscovered into adulthood

• Treatment Options– Resection is the treatment of choice due to risk of infection, malignancy

– Surveillance

– Fetal Surgery

Congenital Pulmonary Airway Malformation

Discussion

Discussion

Discussion

Chest X-Ray, Post-surgical

Kao SW, Zuppan CW, Young LW. AIRP best cases in radiologic-pathologic correlation: type 2 congenital cystic adenomatoid malformation (type 2 congenital pulmonary airway malformation). Radiographics 2011; 31(3): 743-748.

Priest JR, Williams GM, Hill DA, Dehner LP, Jaffé A. Pulmonary cysts in early childhood and the risk of malignancy. Pediatr Pulmonol. 2009;44(1):14-30.

Oermann, Christopher M. Congenital pulmonary airway (cystic adenomatoid) malformation. In: UpToDate, Post, TW (Ed), UpToDate, Waltham, MA, 2014.

Weerakkody, Yuranga and Frank Gaillard. Congenital Pulmonary Airway Malformation. Radiopaedia. Retrieved August 23, 2014. <http://radiopaedia.org/articles/congenital-pulmonary-airway-malformation>.

Lung: Pleuropulmonary Blastoma. Atlas of Genetics and Cytogenetics in Oncology and Haematology. Retrieved August 25, 2014. <http://atlasgeneticsoncology.org/Tumors/PleuropulmblastomID6040.html>.

Mak, S., B. Annan, S. P. G. Padley, A. G. Nicholson. Congenital Pulmonary Airways Malformation: an update. Electronic Presentation Online System. Retrieved August 25, 2014. <http://posterng.netkey.at/esr/viewing/index.php?module=viewing_poster&task=viewsection&pi=125150&ti=414074&searchkey=>.

References