Proliferating cell nuclear antigen (PCNA) in cerebral cavernomas: an immunocytochemical study of 42 cases

The natural history and growth mechanisms of cerebral cavernous angiomas are unclear, which makes them difficult to manage. We attempted to evaluate the evolutive potential of cavernomas by studying the proliferative capacity of cells.

We studied 42 histologically verified cavernomas with monoclonal antibody to proliferating cell nuclear antigen (PCNA), an accessory protein of the cell cycle, the rate of which is increased in proliferative cells. The PCNA Labeling Index (PCNA LI) was calculated in each case, and the results were compared with histologic findings (lacy areas, thick walls, thrombi, hemosiderin) and clinical features (epilepsy, hematomas, pseudotumorous signs).

Thirty-six of 42 cases (85.7%) revealed stained cells. PCNA LI ranged from 1 to 48% (mean: 23.39%). Statistical analyses showed a positive correlation between PCNA LI and the extent of lacy areas (p < 0.05). On the contrary, collagenous-walled and thrombotic areas rarely showed positively stained cells. We found no relationship between PCNA LI and clinical features.

A proliferative capacity of endothelial cells does exist in some areas of cavernomas and may explain, besides thromboses and hemhorrages, the growth and even de novo appearance of these lesions. Occurrence of fragile blood cavities, thickening of others, and changes in blood flow may influence the evolution of lesions. Our results suggest that in cavernomas, some areas may undergo specific changes, which makes them more dynamic lesions than previously thought.