Pituitary gland and Sella turcica in human trisomy 21 fetuses related to axial skeletal development

The purpose of the present investigation was to study the sella turcica/pit uitary gland region in trisomy 21 fetuses and to relate the findings in the region to the ossification pattern in the axial skeleton formed by the cra nial base and spine. Material from 22 human fetuses with trisomy 21, CRL 80 mm to CRL 190 mm, corresponding to gestational ages from 14 to 21 weeks, w as examined and compared with material from gestation-matched normal contro ls, After radiography, tissue blocks from the cranial base, including the p ituitary gland, were examined and compared with those of normal fetuses, Fo ur different types of sella turcica/pituitary gland morphology were observe d. Thirteen fetuses (Type I) were morphologically normal, Minor abnormaliti es occurred in the sella turcica and pituitary gland (adenopituitary gland tissue pharyngeally) in six fetuses (Types II and III). There was agreement between the histologically recorded deviations in the sella turcica and th e radiographic observations of the basisphenoid bone. In three eases (Type IV) out of 22, more pronounced structural abnormalities occurred in the sel la turcica, and radiographically the basisphenoid bone appeared cleft, All sella turcica changes observed in trisomy 21 were situated anteriorly in th e base of the sella, In all cases the basilar part of the occipital bone wa s normal, Minor changes in the sella turcica region were mainly accompanied by cervical vertebral abnormalities, while the most severe abnormalities o ccurred in association with malformations in the lumbar vertebrae. There wa s no association between sella turcica malformations and the absence or pre sence of the nasal bone, Am. J. Med, Genet. 80:494-500, 1998. (C) 1998 Wile y-Liss, Inc.