Mesothelial lesions of the paratesticular region.

Abstract Mesothelial lesions involving the paratesticular region include mesothelial cysts, reactive mesothelial hyperplasia, adenomatoid tumors, benign cystic mesothelioma, well-differentiated papillary mesothelioma, and malignant mesothelioma. The diagnosis and management of these lesions are often difficult for surgical pathologists, surgeons, and oncologists alike. Mesothelial lesions are relatively uncommon and most benign and malignant tumors present as testicular tumors with no specific findings. A preoperative diagnosis of malignancy is rarely made, and there is no established effective therapy for malignant mesothelioma. This article reviews the clinicopathologic features of paratesticular mesothelial lesions with emphasis in their differential diagnosis and prognosis.