Hydrocele : Mesothelial Hyperplasia

In long-standing hydroceles, the mesothelial lining may show florid hyperplasia which may mimic malignant mesothelioma. It is usually an incidental finding and does not cause polypoid, plaque-like, or nodular masses on the surface of tunica vaginalis unlike in mesothelioma. The median age at presentation is around 45 years which is much younger than that for mesothelioma. The background stroma generally shows fibroblastic organization and chronic inflammation. In this image, the fragment on the top left shows surface denudation which is quite common. The fragment on the lower right shows surface proliferation with a hint of papillary architecture.

Reference: Lee S et al. Florid Mesothelial Hyperplasia of the Tunica Vaginalis Mimicking Malignant Mesothelioma : A Clinicopathologic Study of 12 cases. Am J Surg Pathol 2014; 38:54-59.