Thyroid & Adrenal
A brilliantly translucent, loculated, partially compressible, cystic swelling in the posterior triangle of neck in a child is most likely
a. Cystic hygroma (lymphangioma) occurs as a result of sequestration or obstruction of developing lymph vessels in approximately 1 in 12,000 births.
b. Although the lesion can occur anywhere, the most common sites are in the posterior triangle of the neck, axilla, groin, and mediastinum.
c. The cysts are lined by endothelium and filled with lymph. Occasionally unilocular cysts occur, but more often there are multiple cysts infiltrating the surrounding structures and distorting the local anatomy.
d. A particularly troublesome variant of cystic hygroma is that which involves the tongue, floor of the mouth, and structures deep in the neck.
e. Adjacent connective tissue may show extensive lymphocytic infiltration.
f. The mass may be apparent at birth or may appear and enlarge rapidly in the early weeks or months of life as lymph accumulates; most present by age 2 years.
g. Extension of the lesion into the axilla or mediastinum occurs about 10% of the time and can be demonstrated preoperatively by chest x-ray, ultrasound (US), or computed tomographic (CT) scan.
h. Infection within the cysts, usually caused by Streptococcus or Staphylococcus, may occur.
i. In the neck this can cause rapid enlargement, which may result in airway compromise.
j. Rarely, it may be necessary to carry out percutaneous aspiration of a cyst to relieve respiratory distress
k. The diagnosis of cystic hygroma by prenatal US before 30 weeks' gestation has detected a "hidden mortality," as well as a high incidence of associated anomalies, including abnormal karyotypes and hydrops fetalis.
l. Orotracheal intubation or urgent emergency tracheostomy while the infant remains attached to the placenta, the ex utero intrapartum technique (EXIT) procedure, may be necessary to secure the airway.
a. Surgical excision is the treatment of choice for cystic hygromas.
b. Total removal may not be possible because of the extent of the hygroma and its proximity to, and intimate relationship with, adjacent nerves, muscles, and blood vessels .
c. Injection of sclerosing agents (OK-432 or bleomycin) with favorable results has been reported. OK-432 is composed of a lyophilized mixture of group A Streptococcus pyogenes, and has been used in neonates without systemic toxicity. The use of these agents has not been widely adopted.