Cystic Hygroma

Description

• Benign congenital lymphatic mass (LM) that is cystic in nature
  • Most commonly found in the posterior triangle of the neck (75%)
  • Can be found in other sites of the body, including the axilla, superior mediastinum, groin, retroperitoneum, and lower limbs
• Synonym(s): Cystic hygroma and lymphangioma are outdated terms for lymphatic malformation.

Epidemiology

• No gender predominance noted
• Most series report no racial predominance.

Incidence

• Estimated at cases: 1/6,000 to 16,000 live births
• 50–60% of cases found at birth, 90% seen by 2nd year of life

Etiology and Pathophysiology

• Results from maldevelopment or obstruction of lymphatic system
  • Commonly associated with venous malformations, as both tend to develop concurrently
• Decreased outflow of lymphatics to venous system and abnormal budding of lymphatic tissue create noncommunicating lymphatic tissue and resultant formation of cystic components.
• Lesions are typically nonproliferative and rarely undergo spontaneous regression.

Genetics

• Karyotypic abnormalities are often present when a cystic hygroma is found by fetal US.
• Commonly associated karyotypic abnormalities include Turner, Down, Klinefelter syndromes, and trisomies 13 and 18.
• Genomic microarrays may provide genetic information in cases of abnormal US with normal karyotype (1)[A].

Risk Factors

Associated with advanced maternal age or from environmental factors like maternal virus infection or alcohol abuse during pregnancy (2)

General Prevention

• Large lesions may be seen prenatally during 1st or 2nd trimester with fetal US or MRI.
• Bianchi et al. (2)[B] accurately identified 107 of 113 aneuploid cases of cystic hygromas previously diagnosed with chorionic villus using massively parallel sequencing, which is a noninvasive modality.

Commonly Associated Conditions

• Turner syndrome
• Down syndrome
• Klinefelter syndrome
• Trisomy 13
• Trisomy 18
• Cardiac abnormalities
• Noonan syndrome
• Multiple pterygium syndrome
• Achondroplasia
• Fetal alcohol syndrome
• Fetal hydrops