It has been reported that cystic fibrosis is very rare in Asians, and its clinical expression and genetic mutations are different from those found in Caucasians. We report the case of a boy who had chronic diarrhea with failure to thrive and frequent respiratory tract infections beginning at the age of 2 months. He developed bronchiectasis with chronic severe hypoxemia and pancreatic insufficiency by the age of 3 years and 5 months, which raised the consideration of cystic fibrosis. DNA analysis revealed a homozygous R553X mutation, and both his parents were subsequently proven to be R553X carriers. This case is the first report in a Taiwanese with cystic fibrosis attributable to a mutation commonly seen in Caucasians. However, the age of onset was much younger and the clinical course was more severe than those associated with Western patients. We reviewed the eight reported Taiwanese patients with cystic fibrosis, including the present case. We believe that the incidence of cystic fibrosis in Taiwan may be underestimated. Both genetic and environmental factors may play a role in the phenotypic disparity between Asians and Caucasians.

Xanthogranulomatous pyelonephritis is a rare disease in childhood. Because the symptoms and signs are chronic and non-specific, preoperative diagnosis is usually difficult. We report an 8-year-old boy who had an abdominal mass and anemia for more than 6 months. Fever and dyspnea occurred 4 days prior to admission. Ultrasonography revealed an enlarged right kidney with multiple parenchymal hypoechogenic areas, absence of normal parenchymal structures, and perinephric thickening with multiple calcifications. An abdominal computed tomogram demonstrated an irregular, enlarged right kidney with multiple low-density round areas consistent with hydronephrosis and calculi. Diminished excretion of contrast media and a severe perinephric inflammatory reaction were present. Poor right kidney function was demonstrated by Tc99m-diethylenetriamine penta-acetic acid split renal function examination. We diagnosed xanthogranulomatous pyelonephritis preoperatively based on the clinical and radiological features. The child first had drainage of an extrarenal abscess and antibiotic therapy, followed by definitive nephrectomy. The hospital course was complicated with pleural effusion, peritonitis, pelvic abscess, and sepsis. A two-stage nephrectomy requiring less radical resection and decreasing the surgical complications would have been preferable.