[Choledochus carcinoma in choledochal cyst--a rarity. Presentation of the disease with a case report].

Around 1800 choledochal cysts are described in the literature, of which around 6% have turned malignant. The incidence of malignant degeneration increases with age and amounts to as much as 28%. As the prognosis for malignant choledochal cysts is poor, the only therapy is an early cystectomy before the appearance of malignant changes. The diagnosis of the cyst is made using sonography, ERCP and abdominal CT. Histology alone provides conclusive diagnosis of malignant degeneration. The case of a 29-year-old-woman who entered our clinic with non-specific right-side abdominal pains is presented. A choledochal cyst was diagnosed by means of sonography, ERCP and abdominal CT. Intraoperatively, a choledochal carcinoma was found in the choledochal cyst (type Ia according to Todani), with infiltration to the surrounding area as well as liver metastasis. A cystectomy and Roux-Y-hepatico-jejunostomy were performed. The patient died 8 months after the diagnosis.