The desmoid tumor. I. Incidence, sex-, age- and anatomical distribution in the Finnish population.

We have (1) estimated the incidence of desmoid tumor (DT) in the Finnish population, and (2) defined statistically four major age components of the DT with different biological properties. The incidence of the DT, based on admissions to four separate hospitals and on the number of pathological biopsy specimens analyzed at the Central Pathological Laboratory of Helsinki University, is 2.4-4.3 new cases per 10(6) inhabitants per annum. Statistical analysis demonstrated four major age components where the site of the tumor and/or sex of the patient were non-randomly distributed: "juvenile" DT, a predominantly extra-abdominal desmoid tumor of the female sex; "fertile" DT, a nearly exclusively abdominal DT of fertile females; "menopausal" DT, a predominantly abdominal tumor where the sex ratio approaches one:one; and "senescent" DT, where abdominal and extra-abdominal varieties are equally frequently encountered and where the sex ratio of the affected patients is one:one.