Understanding Congenital Lung Malformation (CLM)
What is a CLM?
CLM is an abnormal development of a part of the lung. It can come in many different forms from big or little cysts (congenital pulmonary airway malformation or CPAM), to a solid mass (bronchopulmonary sequestration or BPS), to a combination (hybrid)
- 1 in 2,000 to 12,000 babies are born with CLM
- No known cause as to why they occur
- Usually detected early during screening ultrasound
- 6% of babies may have additional anomalies, typically involving the heart, kidneys, or digestive system
Fetal Center: the first step in CLM care
Multidisciplinary Evaluation: meet with MFM specialist, pediatric surgeon, neonatologist, and other experts who will care for your baby
Comprehensive Imaging: detailed ultrasounds and other tests when indicated to assess your baby's condition and help plan treatment
Coordinated Delivery Planning: our team works to ensure your baby receives immediate specialized care at birth
How is CLM evaluated?
- Regular monitoring with ultrasound surveillance throughout pregnancy is recommended to track changes
- Our medical team will use CVR (CPAM Volume Ratio) to help predict outcomes and plan care
- CVR compares the size of the CLM to the baby's head circumference allowing for tracking throughout pregnancy
- CLMs typically grow rapidly until around 28 weeks gestational age, then their growth slows down compared to the child. The CVR helps your care team track changes over time and make the best decisions for you and your baby's health
(pic: fetal ultrasound of large CPAM with arrow demonstrating the cyst)
How is a CVR > 1.6 treated prenatally?
When a fetus has a congenital lung malformation (CLM) with a CVR > 1.6, there is a high risk of heart failure (hydrops) and fetal demise, therefore, when indicated, treatment is initiated based on the characteristics of the lesion
- Maternal corticosteroids – first-line therapy for a microcytic lesion to reduce size and hydrops risk
- Thoracoamniotic shunt placement – used in large cystic lesions to drain fluid and collapse the cyst causing compression of the heart
- Open fetal surgery (lobectomy or mass resection) – rarely needed and reserved for refractory or life-threatening cases in a fetus prior to 27 weeks gestational age
How is a large CLM treated postnatally?
When a fetus with a large CLM approaches term, some may require surgery at or shortly after delivery
- EXIT-to-resection – rarely needed, but allows resection while maintaining placental support if severe airway or hemodynamic compromise is anticipated at delivery
- C-Section-to-resection – Controlled Cesarean delivery of the child, followed by neonatal resuscitation and immediate resection of the lesion. Typically performed after 27 weeks gestational age in a child with significant compromise from the lesion
- Planned postnatal surgical resection - performed when the child is stable afterbirth within the first week of life
(pic: shows the fetal surgery team preparing for a C-section-to-resection of a large congenital pulmonary airway malformation)
Thoracotomy
Children with a large CLM or those who are symptomatic or unstable will require a resection through an open incision, called a thoracotomy. This only occurs in 20% of the children we treat for CLM.
(pic: child undergoing thoracotomy with CLM resection)
Neonatal Intensive Care
Babies with a large CLM should be delivered at our center where a neonatal intensive care unit (NICU) is available that specializes in the care of these infants and where a pediatric surgeon can immediately evaluate your child. The neonatologist is a specially trained pediatrician that will manage your baby’s medications, feeding, and daily needs while in the NICU.
Once the child is born, a neonatologist will evaluate the baby and make sure the heart and lungs are working appropriately. Some infants will require a breathing tube and machine to assist with breathing. Some may also require medications to help maintain a normal blood pressure.
A tube placed through the mouth (oral gastric or OG) all the way to the stomach. This tube will suck out any fluid with in the stomach to prevent your baby from choking or breathing stomach contents into the lungs and to prevent the intestines from becoming too dilated with air.
Your baby will receive fluids and antibiotics through a special IV called a PICC line, initially through the umbilical cord, then placed in one of the limbs. Because the child will not be initially allowed to eat, they will also receive nutrition through the PICC line called TPN, or total parenteral nutrition. TPN contains protein, fat, sugar, vitamins, and minerals and will meet all your baby’s nutritional needs
How are most CLMs treated postnatally?
Most often, a fetus with a CLM will remain stable throughout pregnancy and can deliver at term. Delivery and postnatal treatment will then depend on the maximum CVR obtained during prenatal care. Our experience at Primary Children's Hospital in Salt Lake City, Utah is extensive
Immediate Postnatal Management
- Routine delivery – vaginal delivery is generally safe if no signs of hydrops or airway obstruction prenatally
- Observation in the newborn period – many infants are asymptomatic at birth, especially with small or stable lesions
- Supportive care only if needed – oxygen, respiratory support, or NICU monitoring if mild distress develops
Definitive Management
The main purposes for surgical resection are to:
- Resolve respiratory symptoms caused by lesion
- Prevent infection (recurrent pneumonia risk)
- Eliminate risk of malignant transformation (rare but possible, e.g., pleuropulmonary blastoma)
- Promote compensatory lung growth
80% of children at Primary Children's Hospital undergo an elective thoracoscopic resection (removal of the CLM through 3 small incisions)
(Pic. Infant undergoing thoracoscopic removal of a CLM)
Lobectomy or Segmentectomy?
The size and location of the CLM within the lung will determine what needs to be removed. In most cases, a lobectomy, or defined part of the lung will be removed. If the CLM is small, a segment of the lobe might only need to be removed, referred to as a segmentectomy. Rarely, the CLM involves multiple lobes, requiring segments of both lobes, or a lobe and segment of another lobe to be removed.
(Pic. Infant undergoing thoracoscopic removal of a CLM)
Segmentectomy
A segmentectomy permits removal of the CLM saving the rest of the normal tissue of the lobe
- This allows for the residual lung to undergo compensatory growth providing more normal lung tissue later in life
- As well as providing the benefits of infection prevention and elimination of malignant transformation
(Pic. Infant undergoing thoracoscopic segmental removal of a CLM)
ICG-Guided Segmentectomy
- ICG stands for Indocyanine Green, which can be given to the infant at the beginning of the case
- Through 3 small incisions (thoracoscopic), using a special scope, the ICG will turn the normal lung green, helping to provide a roadmap for the surgeon to take out only the abnormal part of the lung containing the CLM
- We are able to perform this surgery at Primary Children's Hospital and are actively studying it's benefit in the treatment of children with CLM
(Pic. Infant undergoing thoracoscopic ICG-directed segmental removal of a CLM)
Our Utah Experience: Personalized Care Based on CVR
Our Pulmonary Hypoplasia Program offers Long-term support
For our patients with a large CLM
Children with a large CLM often need long-term follow-up and support. We have a specialized multidisciplinary care clinic at Primary Children's Hospital for kids born with pulmonary hypoplasia (CDH, large CLM, giant omphalocele, PPH) called the Pulmonary Hypoplasia Program (PHP). Your child will follow-up frequently in this clinic and meet with multiple specialists who are experts in this field of care and will make sure they are growing and developing normally.
These specialists include:
- Pediatric Cardiologist
- Pediatric Pulmonologist
- Pediatric Surgeon
- Pediatric Neurologist
- Developmental Pediatrician
- Occupational therapist
- Physical therapist
- Speech therapist
- Dietician
(pic: Dr. Fenton with a patient who was treated with a CPAM)
