Case Reports—PulmonaryProteus Syndrome High-resolution CT and CT Pulmonary Densitovolumetry FindingsIrion, Klaus L. MD, PhD, FBCR, FRCR*; Hocchegger, Bruno MD†; Marchiori, Edson MD, PhD†; Holemans, John A. BSc, MBBS, FRCP, FRCR, FBIR*; Smith, Rupert A. MBChB, DCH, MRCP‡; Raja, Ramesh C. MBChB, FRCR‡; Singanayagam, Selvadurai MBBS, MRCP, DMRD, FRCR‡Author Information *Liverpool Heart and Chest Hospital NHS Trust, and the Royal Liverpool University Hospital, Liverpool, United Kingdom and the Post-Graduation Program in Respiratory Sciences–UFRGS, Porto Alegre †The Post-Graduation Program in Radiology, UFRJ, Rio de Janeiro, and Fluminense Federal University, Niteroi ‡The Pennine Acute Hospitals NHS Trust, Great Manchester, Brazil Reprints: Klaus L. Irion, MD, PhD, 912 Manchester Road, Bury, Postcode: BL9 8DW, UK (e-mail: [email protected]; [email protected]). Journal of Thoracic Imaging: February 2009 - Volume 24 - Issue 1 - p 45-48 doi: 10.1097/RTI.0b013e31818b20cd Buy Metrics Abstract Cystic transformation of the lungs in Proteus syndrome is considered an important manifestation of this disease. We describe a case of an 11-year-old girl with a diagnosis of Proteus syndrome with lung involvement. Low-dose multidetector computed tomography (CT) revealed extensive diffuse cystic lung disease with left lung predominance, affecting mostly the lower lung zones. The cystic lesions had various sizes and variable wall thickness. Postprocessing using CT histogram densitometric volumetry software (CT densitovolumetry), using the threshold −950 Houndsfield units (HU) for quantifying emphysema, revealed that 31% of her total lung volume was composed of areas with CT attenuation values below −950 HU. © 2009 Lippincott Williams & Wilkins, Inc.