Teerasak Phewplung MD, Presenter: Nothing to Disclose

Avram Zohar Traum, Abstract Co-Author: Nothing to Disclose

Ruth Lim MD, Abstract Co-Author: Consultant, Alexion Pharmaceuticals, Inc Officer, New England PET Imaging System

Michael Stanley Gee MD, PhD, Abstract Co-Author: Nothing to Disclose

To determine the clinical significance of incidentally discovered renal cysts in pediatric patients and identify imaging predictors of polycystic kidney disease (PKD).

An IRB-approved, HIPAA-compliant retrospective search of radiology reports from 1989-2013 was performed to identify patients < 18 years old with an imaging exam identifying at least one renal cyst as well as a follow up renal imaging exam for cyst evaluation and/or subsequent clinical evidence of PKD. Electronic medical records and imaging were reviewed. Cysts with clear solid mass components were excluded.

84 pediatric patients with renal cysts were identified (46 females and 38 males; mean age, 9.48 years), including 76 patients with incidentally discovered cysts and 8 patients with cysts identified from screening for family history of PKD. US (81%) was the most common imaging modality for initial cyst identification. Among the incidentally discovered cyst group, 7.9% (6/76) were found to have PKD compared with 100% (8/8) patients with cysts plus a positive family history of PKD. Multiple cysts or bilateral cysts were imaging features associated with a significantly higher (P < 0.01, Fisher’s Exact Test) incidence of PKD, both for the entire study population (12/14 and 11/14, respectively) and the incidentally discovered cyst group (5/5 and 5/5, respectively). Renal cyst size or complexity was not significantly associated with PKD. 74 patients had a followup renal imaging exam (mean time 36.8 months from initial exam), and an increase in cyst size on the followup study was associated with a higher incidence of PKD (3/5 vs 1/69; P < 0.05). No malignancies were identified in the study population, although one case was found to be a multilocular cystic nephroma on follow up imaging and surgery.

Incidentally discovered renal cysts in pediatric patients are associated with a small but nonzero risk of PKD. Among cyst characteristics, bilaterality, multiplicity, and increased size on followup imaging were associated with significant elevation in PKD risk.

Pediatric patients with bilateral, multiple, or enlarging renal cysts should be carefully screened for clinical/family evidence of PKD.

Phewplung, T, Traum, A, Lim, R, Gee, M, Clinical Significance of Incidentally Discovered Renal Cysts in Pediatric Patients.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008762.html