Castleman's disease(Giant lymph node hyperplasia) is a disorder characterized by massive enlargement of lymph node in the mediastinum and occurs rarely in the neck, axillary area and abdomen. Giant lymph node hyperplasia was first described by Castleman in 1954. The Castleman's disease in the retropertoneum is the extremely rare disease according to the literatures.

The authors experienced a Castleman's disease in the retroperitoneum of 40 year old male patient who had been suffered from intermittent abdominal discomfort and indigestion. and so reported the case with thereview of the literatures.

Cholesteatoma is a form of squamous metaplasia resulting in a collection of keratin composed of desquamated epithelial cells and occurs extremely rarely in the urinary tract.

Cholesteatoma of the renal plvis was first described by Ebstein in 1982. Since the fewer than 30 cases have been reported until now in the literatures.

The authors experienced a cholesteatoma of the renal pelvis in 42 years old female patient who had been suffered from intermittent right flank pain, and reported the case with review of the literatures.