At least 2 years of multiple and various medically unexplained symptoms and persistent refusal to accept advice and reassurance from doctors, accompanied with impaired functioning.
To somatize is to present with medical symptoms when the underlying problem is really psychological.

Thomas T, Booth S, Earl H and Lennox G. Somatization disorder and cancer: A case history and review. Palliative and Supportive Care. 2004. 2:409-413.