[size=20px]A 5-month-old girl is being seen in your clinic for a right lower lobe cystic lung mass. She had a CXR performed for a chronic cough and the lesion was seen. Chest CT scan was performed and shows a macrocystic 4 cm lesion in the right lower lobe, with question of a feeding vessel. Her mother had serial prenatal ultrasounds for placental position and the lesion had not been seen. In this child’s history, which factor is most concerning for possible malignancy?

 

A Absence of lesion on prenatal ultrasound

 

B Location of lesion

 

C Presence of systemic feeding vessel

 

D Size of lesion[/size]

D

correct answer

A Absence of lesion on prenatal ultrasound

 

The most common presentation of cystic lung masses in infants and children is identification of the lesion in asymptomatic patients. Recent studies have attempted to establish certain features that are associated with the need for excision of the lesion. The acronym CPAM may be used to remember these factors:

• Clinical symptoms: Symptoms of respiratory distress attributable to the lesion are an indication for resection. Episodic infection of the abnormal lung should also warrant removal.
  
• Pathology: Intralobar bronchopulmonary sequestration has the highest risk for infection and is an indication for removal. In stratifying lesions from higher to lower risk of infection and symptoms, macrocystic congenital airway malformation (CPAM) and bronchogenic cyst can be categorized as medium to higher risk, while bronchial atresia, microcystic CPAM and extralobar sequestration may be considered lower risk. Bilateral lesions signify a higher risk for malignancy and further workup is required. Systemic feeding vessel is not associated with higher risk of symptoms or malignancy.
  
• Age at diagnosis: Postnally diagnosed cystic lesions have a higher likelihood of harboring malignancy, over 8%.
  
• Malignant potential: Lesions in patients with positive DICER1 testing and/or family history of DICER1 have a higher likelihood of harboring malignancy, specifically, pleuropulmonary blastoma (PPB). Regarding PPB, the median ages at diagnosis for type I, type II, and type III patients were 8, 35, and 41 months, respectively. The 5-year overall survival (OS) rate for type I/Ir patients was 91%; all deaths in this group were due to progression to type II or III. OS was significantly better for type II versus type III (P = .0061). Size of lesion may also be associated with cancer as lesions >5 cm in diameter have higher risk of malignancy than those < 3cm.
  

Kunisaki et al. reported on a retrospective cohort study of 521 primary lung lesions managed at 11 children’s hospitals. Univariate analysis showed that none of the prenatally diagnosed lesions were malignant, but about 9% of lesions diagnosed postnatally were malignant. Over half of the malignant lesions were associated with DICER 1. No malignant lesion had a systemic feeding vessel. Unfortunately, the CT scan is only 33% sensitive in predicting malignancy. Multivariate regression showed that increased suspicion of malignancy by CT and bilateral disease were significant predictors of malignant pathology.