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Cystic Hygroma Exacerbated by Pregnancy

A 26-year-old woman was examined in the emergency room for a 2-month history ofa progressively enlarging left neck mass that had developed immediately after a normal spontaneous vaginal delivery (figure 1). Approximately 1 year earlier during a prior pregnancy, a smaller mass had arisen in the same location ; findings on fine-needle aspir ation biopsy at that time were nondiagnostic. Weobtained magnetic resonance imaging (MRI), which identified an 18 x 10-cm homogeneous cystic structure in the lateral neck; the mass extended from the tail of the parot id gland to the clavicle (figure 2) . After an attempt at aspiration had failed , the mass was excised through a MacFee incision without complication (figure 3). On gross examination intraoperatively, the tumor exhibited thin walls and a venous hue (figure 4). Findings on pathologic analysis were consistent with a cystic hygroma. Cystic hygromas are lymphatic malformations.Approximately 65 to 75% ofthese macrocystic, well-circumscribed lesions appear in newborns, and 80 to 90% appear within 3 years of birth . Fewer than 100 cases of adult cystic hygroma have been reported in the literature. Figure 2. A: Axial MRJ shows the large, thin-walled, cystic, left lateral neck structure with tracheal deviation to the right. B: Coronal MRJshows that the mass extendsfront the tail ofthe parotid to the clavicle.