Efficacy of OK-432 local injection for the treatment of a neonatal branchial cleft cyst: a case report.

We herein present a case of a neonatal cervical cyst, which was diagnosed prenatally, and markedly decreased in size and disappeared after a local injection therapy of OK-432. A 0-day-old boy had an abnormal prenatal ultrasonography scan suggestive of rt. cervical cyst, measuring about 25 mm in diameter at 29 weeks' gestation. At birth, an elastic soft mass, measuring about 30 mm in diameter, was found on the right side of his neck. Computed tomography (CT) scans showed a giant cyst, which extended from the upper level of epipharynx to the upper mediastinum, and the contents were air and fluid. At 20 days of age, ultrasonography (US)-guided needle aspiration was performed. The aspirated fluid contained no epithelial cells, but many lymphocytes and neutrophils based on a cytological analysis. After the local injection of OK-432 had been performed four times, the right neck cyst had almost completely disappeared on US scans. During the local injection therapy, we analyzed the other sample of the second aspiration fluid of the neck cyst. Several clusters of epithelial cells, columnar epithelium, squamous cells, and ciliated epithelium were thus cytologically observed. Therefore, a final diagnosis of a branchial cleft cyst was made. The local injection of OK-432 was thus found to be an effective treatment for branchial cleft cysts.