Proteus syndrome has also been termed ‘elattoproteus syndrome’ or the ‘elephant man disease’. It is a rare genetic condition in which some parts of the body start to grow too much, in a random manner.
As a result of the uncontrolled proliferation of various tissues, as in the skin and the bones, with no apparent pattern, some body parts finally come to a size out of all proportion to the rest of the body. It is present at birth but manifests only after a few months, typically at 6 to 18 months, and worsens with age.
Its prevalence is very low, with less than one in a million being affected anywhere in the world.
Keratinocytic nevi are frequent in this condition, occurring as velvety overgrowths of the skin, being found in at least half the people affected with Proteus syndrome. This is the only lesion in this condition that remains stable with time.
The skin also often shows areas of dermal hypoplasia, or areas with abnormal capillaries called telangiectatic nevi, or connective tissue nevi in the palms and the soles. These latter produce cerebriform (grooved deeply, like the cerebrum or outer layer of the brain) patterns in the skin. The thick, firm, furrowed skin in this case is due to epidermal connective tissue hyperplasia. It is pathognomonic of Proteus syndrome.
Similar hyperplasia of the vascular system can occur causing vascular malformations. Abnormal distribution of fat tissue may occur leading to lipoma formation. Again, abnormal bone thickening may occur in the skeletal system, such as in the cranial or limb bones, resulting in progressive malformations. Spinal overgrowth may also occur.
Proteus syndrome may include symptoms of neurological disease, such as mental retardation, visual loss, and epileptic seizures. Some patients have a recognizable alteration of the facial outline - including down-slanting eyes, a low nasal bridge, a gaping mouth, and a long face – which is a marker for neurological involvement.
Individuals with Proteus syndrome may have a higher risk of developing thrombosis, especially deep vein thrombosis, and benign tumors, for the same reason as causes overgrowth of other tissues. This can cause pulmonary embolism.
The cause of Proteus syndrome is thought to be a somatic mutation which occurs in the post-zygotic stage of embryonic life. This cell line proliferates in some areas while the normal cells continue to develop in other areas. The body thus has a mixture of cells which is termed mosaicism.
Diagnosis and Management
Proteus syndrome is diagnosed on the basis of strict guidelines which include the medical history, the symptoms present, a complete physical examination, and laboratory testing. When serious medical problems are present, they need to be treated appropriately. Disfigurement may occur due to these lesions, which may require cosmetic laser surgery or surgical removal.