Chromatin texture analysis of cortical adrenal gland adenomas, including incidentalomas, and adjacent normal-appearing cortical tissue

OBJECTIVE: To describe, by morphometric and chromatin texture analysis, a s eries of adrenal gland lesions, including Gushing's and Conn's adenomas and incidentalomas. STUDY DESIGN: The material for the study consisted of five consecutive case s of incidentaloma, three eases of Conn's adenoma and three cases of Gushin g's adenoma. Also included were five cases ofnduenaE carcinoma. Sections we re stained according to the Feulgen procedure. Measurements were taken from the nodules and from two different zones, identified as outer and inner pa rts, of the normal-appearing adrenal cortex adjacent to the tumor. Data on approximately 50 nuclei were recorded for each of these three sites (tumor and outer and inner normal-appearing adrenal cortex). The nuclei were subje cted to feature extraction and were analyzed by identification procedures-i .e., establishing nuclear and lesion signatures. RESULTS: The total optical density (OD) distributions of the nuclei from th e normal-appearing adrenal cortex pointed to their diploid or near-diploid nature. In incidentalomas there was a very small increase in the number of nuclei, with increased total OD. In Conn's adenoma there was a noticeable b ut modest extension of the total OD distribution into the higher OD range. This trend continued for Gushing's adenoma. The pixel OD histograms for nuc lei from normal-appearing tissue and from incidentalomas were hardly distin guishable. Starting with nuclei from Conn's adenoma, a shift toward lower p ixel OD values began. The trend continued for nuclei from Gushing's adenoma and was very pronounced for nuclei from carcinoma. The nuclear signatures showed no appreciable difference between nuclei from normal-appearing corte x and from incidentaloma. Nuclei from Conn's adenoma were move similar to t hose from normal tissue in their signatures than nuclei from Gushing's aden oma. In fact, the nuclear signatures from Gushing's adenoma were almost ide ntical to those of carcinoma. The lesion signatures for normal tissue, inci dentaloma and Conn's adenoma confirmed the results seen in the nuclear sign atures. There was a very modest increase in the number of nuclei with great er deviation from normal in incidentalomas, and the trend was more obvious in Conn's adenoma. However, in Gushing's adenoma there was a very substanti al increase in the number of nuclei, with large deviations of their nuclear chromatin texture from normal. CONCLUSION: Computer-assisted analysis of nuclear characteristics proved us eful in identifying and describing differences between groups of tumors ari sing in the adrenal cortex and highlighted the similarity between incidenta lomas and adjacent normal-appearing cortex and between Gushing's adenoma an d adrenal carcinoma.