Angiomyofibroblastoma is an uncommon benign mesenchymal tumor. It occurs almost in the vulvovaginal area of women, but can also be observed in men.

The gross features of AMFB are well-circumscribed. Usually, most tumors grow slowly, and patients do not feel pain. It also has low tendency for local recurrence.

Microscopical examination shows abundant thin-walled blood vessels with hypocellular and hypercellular areas.

A major risk factor for the development of testis cancer is cryptorchidism (undescended testicles). It is generally believed that the presence of a tumor contributes to cryptorchidism; when cryptorchidism occurs in conjunction with a tumor then the tumor tends to be large. Other risk factors include inguinal hernias, Klinefelter syndrome, and mumps orchitis. Physical activity is associated with decreased risk and sedentary lifestyle is associated with increased risk. Early onset of male characteristics is associated with increased risk. These may reflect endogenous or environmental hormones.

Higher rates of testicular cancer in Western nations have been linked to the use of cannabis.

Most testicular germ cell tumors have too many chromosomes, and most often they are triploid to tetraploid. An isochromosome 12p (the short arm of chromosome 12 on both sides of the same centromere) is present in about 80% of the testicular cancers, and also the other cancers usually have extra material from this chromosome arm through other mechanisms of genomic amplification.