Answer: Infarct associated with vasculitis

Histology: Within the testis is a localized area of infarction with extensive recent hemorrhage and necrotic seminiferous tubules. The lesion does not involve the entire testis. Away from the necrotic testis are several vessels which appear to be small to medium sized arteries with fibrinoid necrosis either circumferentially or focally involving the muscle wall. The fibrinoid necrosis is associated with karyorrhectic debris. No carcinoma is identified within the specimen.

Discussion: Whenever one sees a localized area of necrosis within the testis one should always look for surrounding vasculitis. Testicular torsion consists of twisting of the spermatic cord where the entire blood supply to the testis may be compromised giving rise to a totally infracted testis. If one sees extensive hemorrhage and a localized mass within the testis it is reasonable to look for choriocarcinoma as it may be associated with extensive necrosis and hemorrhage. However one would not see within the hemorrhage ghosts of necrotic seminiferous tubules as seen in the current case, but would rather identify tumor. The findings in the current case are typical of an infarct associated with a recent hemorrhage. Whenever one is looking for vasculitis in the area of necrosis one should always make sure one looks for vessels outside the immediate area of the necrosis to make sure that the necrosis in the vessel wall is not merely secondary to the necrosis. In the current case, in addition to the affected vessels being outside of the immediate area of necrosis they are also involved focally by fibrinoid necrosis which is a specific finding for vasculitis. Vessels secondarily involved by necrosis show diffuse inflammation throughout the vessel. Whereas vasculitis in the testis may be the manifestation of systemic vasculitis such as polyarteritis nodosa, in most cases it represents isolated vasculitis unrelated to a systemic disease. However, morphologically one can not distinguish isolated versus systemic vasculitis morphologically. Consequently, one should always put in the pathology report that while this may represent an isolated vasculitis of the testis, systemic vasculitis should be ruled out clinically.