Histologic variations in the epididymis: findings in 167 orchiectomy specimens.

Nonpathologic morphologic variations in the epididymal histology in 167 orchiectomy specimens were analyzed to assess and document the nature, frequency, and possible relation to patient age and underlying testicular pathology. Variations in histology included intranuclear eosinophilic inclusions, lipofuscin pigment, cribriform hyperplasia, Paneth cell-like metaplasia, and nuclear atypia. Intranuclear eosinophilic inclusions were observed in 72.5% of patients, and they appeared to occur at an older age than cribriform hyperplasia and Paneth cell-like metaplasia. Lipofuscin pigment was found in 32.9% of patients; this change was observed predominantly in ductuli efferentes and was more commonly associated with obstructive changes. Cribriform hyperplasia was seen in 41.9% of patients, and it occurred in 1 normal testis and in 33 testes with diverse pathologic alterations. Paneth cell-like metaplasia characterized by bright eosinophilic intracytoplasmic hyaline-like granules and globules, was present in 8.3% of patients and was accompanied by changes of obstruction in almost all instances. The globules were strongly periodic acid-Schiff positive, both before and after diastase digestion, and were negative for chromogranin A, KP-1, and MAC387 immunostains. Nuclear atypia, similar to that seen in seminal vesicles, was focally present in 13.8% of patients and tended to occur at an older age. The authors conclude that variations in epididymal morphology are fairly common and, therefore, surgical pathologists should be aware of these changes. Although exuberant in some patients, in no cases did these variations cause serious diagnostic problems.