[Diagnosis of pituitary microadenoma by thin-section hypocycloidal tomography (author's transl)]

The authors stressed the reliability of lateral thin-section hypocycloidal tomography not only for the detection of pituitary microadenomas but also as an aid in surgical removal of them. Fourteen women with secondary amenorrhea were studied of which 13 cases showed high serum prolactin levels. Transsphenoidal surgery confirmed the presence of microadenomas less than 10 mm in all cases. The sellar volume measurement from plain radiographs of the skull was normal in all cases. The contour of the sella on plain lateral radiographs was abnormal in 4 cases (28.6%); double floor in 2 cases and localized ballooning in 2 cases. Hypocycloidal tomography was carried out at 2 mm intervals in both anteroposterior projection and lateral projection. Anteroposterior tomograms were abnormal in only 4 cases; each case with destruction of the sellar floor with small tumor shadow in the sphenoid sinus, central depression, lateral depression and sloping of the sellar floor. Lateral tomograms were, on the other hand, abnormal in all cases. Localized expansion with thinning in the anterior or anteroinferior portion of the sellar wall was found in 11 cases and the same finding in the inferior or inferoposterior portion of the sellar wall associated with thinning of the dorsum sellae was present in 3 cases. Lateral tomograms were considered more sensitive than anteroposterior tomograms from these results. We also studied the reliability of hypocycloidal tomography in the accurate localization of the tumor in comparing with the actual location of the tumor from the operative findings. In 12 cases the location of the tumor defined by hypocycloidal tomography was coincident with that by surgery. Moreover, when the sellar destruction was shown to be larger by hypocycloidal tomography, size of the tumor tended to be larger. These results suggested hypocycloidal tomography would be an accurate aid in surgical procedures.