The diagnostic value of morphometry on blood lymphocytes in erythrodermic actinic reticuloid

As the differential diagnosis of erythrodermic actinic reticuloid vs Sézary syndrome (SS) can be very difficult, we examined the value of the nuclear contour index (NCI) on blood lymphocytes as the criterion for differential diagnoses. The NCI is defined as the nuclear parameter divided by the square root of the nuclear area. Three different parameters were studied: mean NCI, percentage of cells with an NCI of 6.5 or greater, and the highest NCI. These indexes were studied on blood lymphocyte samples obtained from 10 patients with erythrodermic actinic reticuloid and were compared with the findings in 10 patients with other benign forms of erythroderma and in seven patients suffering from SS.

The patients with erythrodermic actinic reticuloid differed significantly from the group with SS regarding the percentage of cells with an NCI of 6.5 or greater and the highest NCI, but not when the mean NCI was considered. All three parameters revealed nonsignificant results for erythrodermic actinic reticuloid compared with other benign forms of erythroderma. The group with SS differed significantly from the patients with other benign forms of erythroderma regarding all three parameters. By combining three morphometric criteria (mean NCI, > or = 5.5; > 30% lymphoid cells with an NCI of > or = 6.5; and highest NCI, > or = 11.5), all patients with erythrodermic actinic reticuloid or other benign forms of erythroderma and six of the seven patients with SS were correctly classified.

Our data indicate that assessment of the NCI on peripheral blood lymphocytes is of value in the differential diagnosis of erythrodermic actinic reticuloid vs SS.