Intratubular Spermatic Granulomas of the Canine Efferent Ductules

Spermatic granulomas are inflammatory lesions that occur in the efferent ductule and epididymis of humans, goats, rats, and bulls. Three clinically normal dogs from a control group had histologic lesions of the initial segment of the caput epididymis consisting of intratubular spermatic granulomas. The granulomas were located within the efferent ductules, and the inflammatory response consisted primarily of aggregates of spermiophagic macrophages in the ductules. Sperm stasis of the affected ductules was evident by the dilation and accumulation of large numbers of spermatozoa in adjacent cross-sections of efferent ductules. Blind-ending efferent ductules were demonstrated by serially sectioning the initial segment of the epididymis. The intratubular granulomas did not completely occlude the outflow tract because spermatozoa were present in the cauda epididymis. While spermatic granulomas can be induced by trauma, infection, or toxins, spontaneous granulomas due to blind-ending ductules should be considered as a differential. Clinical history, location of the granuloma, and serial sectioning can help determine the most likely etiology in early cases.