To date, there has been no histologic evidence of a viral or autoimmune cause.
Although African hedgehogs are bred commercially for the pet trade, their behavior remains that of non-domesticated animals.
Note that oral tumors are extremely common in hedgehogs.
From all I researched at the time, average recurrence for mammary tumours is 8 months and death by a year.
During the treatment period, the cage is lined with paper that is changed daily.
Unfamiliar sounds or movements will often cause a hedgehog to assume its defensive posture.