Capsule: see article by Vincenzo Suma, MD

Case report

A 24 year-old G₂P₀₀₁₀ patient was referred for ultrasound at 20 weeks of gestation because of the discovery of a cystic mass extending from the left lateral chest area towards the axilla.

The examination confirmed the presence of a cystic structure with trabecula located in the left axillary region of the fetus, measuring 20x10x15 mm (fig. 1,2). The diagnosis of axillary cystic hygroma was suggested. The fetal biometry was within the normal range for gestational age, and there were no associated anomalies. An amniocentesis was performed the next day and demonstrated a normal female karyotype.

On follow-up examination at 25 weeks, the cystic mass increased moderately to 23 x 20 mm. Overall, the mass had grown much less rapidly than the fetus, giving the impression of reduction (fig. 3). The axillary artery could be seen with color Doppler to surround it. At 34 weeks,  the structure decreased in size and measured just 8 x 8 mm and the trabecula disappeared (fig. 4).

Fig. 1: Axillary cystic hygroma at 20 weeks. Axial view.

Fig. 2: Longitudinal view, note the relationship with the ribs (R), heart (h) and humerus (H). 

Fig. 3: At 25 weeks, the mass appears smaller...

Fig. 4: ...and at 34 weeks it only measured 8 mm.

The findings suggested intrauterine involution of the cystic hygroma. There were no other complications of the pregnancy, and the baby was delivered at term.

The neonatal course was unremarkable. At physical exmination a small nodule could be palpated in the left axilla.

The child is now 2 years old, and an ultrasound examination performed with a 7.5 Mhz transducer is normal. No other complications have developed so far.

Discussion

For the discussion of axillary cystic hygroma, please refer to the article by Vincenzo Suma, MD. The following discussion refers only to the present case.

There are three reports mentioning the prenatal diagnosis of axillary cystic hygromas in utero^1-3. In all three cases a superficial, multicystic and complex mass involving the skin and soft tissues of the axilla was identified, the karyotype was normal and there were no associated anomalies. All three patients underwent resection of the mass after birth and did well after the procedure.

Three reports mention the spontaneous resolution of nuchal cystic hygromas in utero. One was associated with a normal karyotype and two with Turner syndrome^4-6.

To the best of our knowledge, this is the first report of spontaneous resolution of an axillary cystic hygroma in utero.

References

1. Benacerraf BR, Frigoletto FD.: Prenatal sonographic diagnosis of isolated congenital cystic hygroma unassociated with lymphedema or other morphologic abnormality. J Ultrasound Med 6:63-6, 1987.

2. Hoffman-Tretin J, Koenigsberg M, et al.: Antenatal demonstration of axillary cystic hygroma. J Ultrasound Med 7:233-235, 1988.

3. Suma V, Marini A, Gamba P, et al.: Cystic hygroma, axillary. The Fetus 2:2281-1,6,1992.

4. Mostello DJ, Bofinger MK, Siddiqi TA.: Spontaneous resolution of fetal cystic hygroma and hydrops in Turner syndrome. Obstet Gynecol 73:862-5,1988.

5.Chodirker BN, Harman CR, Greenberg CR.: Spontaneous resolution of a cystic hygroma in a fetus with Turner syndrome. Prenat Diagn 8:291-6,1988.

6. Macken MB, Grantmyre EB, Vincer MJ.: Regression of nuchal cystic hygroma in utero. J Ultrasound Med 8:101-3,1989.