Brain metastases' radiologic phenotypes: correlation between tumor's consistency, extent of edema, histologic features and vascular territory affected.

[INTRODUCTION] Morbidity and mortality related to brain metastases (BM) are affected by their intracranial distribution, consistency (solid vs. cystic), and extent of peritumoral brain edema. We have hypothesized that the vascular properties of the different vascular territories of the brain may influence differences in BM's radiologic morphologies.

[METHODS] This is a retrospective study of all adult patients (age ≥18 years) with histopathological confirmed BM. Based on radiologic features, the patients were divided into 3 groups: solid, cystic-necrotic, and purely cystic. Data on different variables were extracted for eligible cases and used for statistical-based comparisons between groups.

[RESULTS] Following categorization according to radiologic phenotype, 61 (32.3%), 85 (45%), and 43 (22.7%) cases were considered solid, cystic-necrotic, and purely cystic, respectively. On univariate analysis, the purely cystic phenotype was significantly associated with male gender, posterior cerebral circulation, lung cancer (vs. breast cancer), neuroendocrine tumor, and older age. On multivariate analysis, posterior circulation (OR = 8.782, < 0.001), neuroendocrine tumor (OR = 4.539, = 0.046) and older age (OR = 1.075, = 0.021) remained significant. In addition, on multivariate analysis, severe edema was significantly associated with the solid phenotype, anterior circulation and age < 55 years cases.

[CONCLUSION] The two cerebral circulations are significantly associated with different BM radiologic phenotypes as well as with differences in the extent of peri-lesional brain edema. Furthermore, several epidemiological, histological and molecular variables are also associated with these important radiologic features. As our data on factors associated with BM radiologic morphologies grows, so our understanding of the relevant pathophysiology will expand, leading to practical implications affecting morbidity and prognosis.