Structural and morphometric analysis of parakeratotic and dyskeratotic cells exfoliated from various vulvar lesions. Correlation with data from cervical cytology.

Smears were taken from the vulvar skin of 123 patients (21 with normal-appearing skin and 12 with dystrophic, 29 with benign, 20 with precancerous and 53 with malignant conditions). In each case, 20 nucleated horny squames with the highest visible degree of abnormality were identified in the smear. The cytoplasmic and nuclear structures of these cells were analyzed, and the cytoplasmic and nuclear perimeters were measured by a graphics tablet (digitizing board) equipped with a camera lucida system. Five cytomorphometric parameters were calculated: cytoplasmic and nuclear areas and shape factors and the relative nuclear area. A stepwise multivariate discriminant analysis was used to evaluate the statistical significance of the parameters. Structurally, the cells from different vulvar conditions did not differ much from each other except in the formation of small cellular projections ("pseudopodia"), which were found significantly more frequently in precancerous and cancerous lesions than in others. Nuclear degeneration was a general finding in all examined cases of all conditions. Morphometric analysis revealed cytoplasmic pleomorphism to be the predominant feature associated with increasing degrees of malignancy. There was no significant increase in the relative nuclear area with increasing malignancy because the cytoplasmic and nuclear areas enlarged almost simultaneously. The cellular features found in nucleated horny cells exfoliated from various vulvar lesions are quite different from the well-known attributes of squamous epithelial cells originating from comparable conditions of the uterine cervix.