Radiologic manifestations of Proteus syndrome.

Proteus syndrome is a sporadic disorder named for its highly variable manifestations. The disease causes tissue overgrowth in a mosaic pattern and may affect tissues derived from any germinal layer. The disease process is not usually apparent at birth but develops rapidly in childhood. Common manifestations include macrodactyly, vertebral abnormalities, asymmetric limb overgrowth and length discrepancy, hyperostosis, abnormal and asymmetric fat distribution, asymmetric muscle development, connective-tissue nevi, and vascular malformations. The features of Proteus syndrome indicate that the condition may be caused by a somatic alteration in a gene, but no specific genetic mutation has yet been identified. Therefore, the diagnosis and management of the disease depend heavily on clinical evaluation and imaging. Although the manifestations of Proteus syndrome are highly variable, accurate diagnosis is possible if standard diagnostic criteria are followed and if disease features are assessed in comparison with those found in similar syndromes.