Analysis of histological and immunohistochemical patterns of benign and malignant adrenocortical tumors by computerized morphometry

Diagnosis of benign and purely localized malignant adrenocortical lesions is still a complex issue. More-over, histology-based diagnosis may suffer of a moment of subjectivity due to inter- and intra-individualvariations. The aim of the present study was to assess, by computerized morphometry, the morphologicalfeatures in benign and malignant adrenocortical neoplasms.Eleven adrenocortical adenomas (ACA) were compared with 18 adrenocortical cancers (ACC). Allspecimens were stained with H&E, cellular proliferation marker Ki-67 and reticulin. We generated amorphometric model based on the analysis of volume fractions occupied by Ki-67 positive and nega-tive cells (nuclei and cytoplasm), vascular and inflammatory compartment; we also analyzed the surfacefraction occupied by reticulin. We compared the quantitative data of Ki-67 obtained by morphometrywith the quantification resulting from pathologist’s visual reading.The volume fraction of Ki-67 positive cells in ACCs was higher than in ACAs. The volume fraction ofnuclei in unit volume and the nuclear/cytoplasmic ratio in both Ki-67 negative cells and Ki-67 positivecells were prominent in ACCs. The surface fraction of reticulin was considerably lower in ACCs.Our computerized morphometric model is simple, reproducible and can be used by the pathologist inthe histological workup of adrenocortical tumors to achieve precise and reader-independent quantifica-tion of several morphological characteristics of adrenocortical tumors.