1333. A rabbit grows a "horn" above the left eye

"The rabbit grows a horn," I said to Julia.
"Why would a rabbit grow a horn?"
"Because he is horny."
Seriously, I had a case of an 8-year-old rabbit growing a prominent "horn" in around 2 weeks.
Dr Daniel was thinking it could be a sarcoma. My advice would be to excise it. X-rays showed a growth. Dr Daniel and I operated. Histology indicated a sarcoma.
"It grows big very fast," the neurology nurse said to me. "One week ago, it was a small lump."
"It is likely to recur," I said. "It was too big to completely excise all tissues. The bony skull would have remnants of the cells.