Vilanova, 44, underwent an operation on his parotid gland on Thursday and faces six weeks of chemotherapy.
Barcelona confirmed the news on Wednesday night, coincidentally, on the same day Abidal returned to training for the first time since he needed a liver transplant in April.
Abidal's return was a significant step in his bid to continue his career, however, he admitted he had been left thinking only about his ailing boss.
"I confirm you that I have started again the collective training with the group," he wrote on his Facebook page.
"I hope to come back soon on the fields, but I can't stop thinking of our coach, Tito Vilanova: I wish him and his family, a lot of courage!"