[Crohn disease and squamous cell carcinoma of the anorectal transition].

Squamous cell carcinoma of the anorectal junction originated from anal fistulas in two female patients with Crohn's disease which have been suffering from anal and rectovaginal fistulas for many years. In addition one tumour showed paraneoplastic parathyroid hormone synthesis. This findings point out Crohn's disease as a premalignant lesion. Chronic fistulas associated with Crohn's disease must be followed up carefully by clinical examination, endoscopy and biopsy. To prevent malignancy and to cure the anal region and the origin of such fistulas, resective surgical technics should be taken into consideration early.