Hypoplastic thymus and T-cell reduction in EECUT syndrome.

We report on a patient with EEC/EECUT syndrome and concomitant hypoplasia of the thymus and reduction of T cells in secondary lymphatic organs. The patient was born prematurely at 35 weeks of gestational age and exhibited ectodermal dysplasia, ectrodactyly, cleft palate and urinary tract abnormalities. On the left side, a large ureterocele was present. On the right side, an atretic ureter was found. Both conditions had led to intrauterine hydronephrosis, renal dysplasia, oligohydramnios, pulmonary hypoplasia, and death of the child. Ureteral malformations are thought to be of epithelial origin. Autopsy showed only small rudiments of thymic tissue containing single epithelial cells, but were completely devoid of Hassall corpuscules. Again, this clearly points to an ectodermal defect. Although there was severe reduction of T cells in secondary lymphatic organs, the thymic defect would not have necessarily led to immunological deficiency; perhaps this is the reason that an epithelial defect in the thymus of patients with EEC syndrome has not yet been reported. With regard to an updating of the diagnosis of the EEC/EECUT syndrome, an "EEC/EECUT plus" syndrome is suggested.