Morphometric analysis of germinal centers in nonthymomatous patients with myasthenia gravis

A morphometric analysis of germinal centers (GCs) in the thymus of nonthymomatous patients with myasthenia gravis was performed in 26 patients, including 14 women and 12 men. The GCs were evaluated for number, diameter, perimeter, and cross-sectional area using a computerized interactive morphometric analysis. The GCs ranged from 2 to 19 per case, with an average diameter of 0.02 to 0.43 mm, a perimeter of 0.38 to 1.35 mm, and a cross-sectional area of 0.01 to 0.14 mm2. In thymic sections with fewer than five GCs, the GCs had a mean area of 0.05 mm2, a perimeter of 0.84 mm, and a diameter of 0.24 mm. In thymic sections containing five or more GCs, the GCs had a mean area of 0.04 mm2, a perimeter of 0.62 mm, and a diameter of 0.19 mm. The clinical improvement in these patients inversely correlated with the above parameters, with improvement being observed in patients whose GCs had a mean area of 0.02 mm2, a perimeter of 0.58 mm, and a diameter of 0.17 mm. No correlation was observed between the number of GCs and clinical improvement. The results of our study appear to indicate that computerized interactive morphometric analysis may represent a potentially useful method for the evaluation of the morphometric features of thymic GCs and their correlation with clinical outcome in patients with myasthenia gravis.