The disease appears soon after birth and
progresses at a variable rate leading to gross deformity in later childhood.
Some patients are born with large, complex, mixed vascular malformations.
Overgrowth, usually digital, is noted during infancy. In childhood, patients
may also develop linear epidermal nevi. The skeletal system is mainly
affected with hemihypertrophy, macrodactyly, scoliosis, and exostoses over
the skull. Intelligence is usually normal. Spinal compromise may develop in
Proteus syndrome from vertebral anomalies (e.g., angular kyphoscoliosis) or
tumor infiltration. There may be associated pulmonary involvement (rapidly
progressive diffuse cystic emphysematous pulmonary disease that is
potentially fatal, secondary chronic restrictive pulmonary disease from
scoliosis). Pulmonary hypertension is often a feature of this syndrome. Anomalies of the
cervical spine (vertebral enlargement, hemivertebrae, dysplastic vertebrae, dystrophic
intervertebral diseases) are common and may predispose to airway obstruction. The
prognosis is unknown. Surgical removal of lymphatic, fatty, or hemangiomatous elements
is difficult and results in unsightly scars and keloids. A predisposition to
tumors exists, especially cystadenomas of the ovary and mesothelioma. Thrombosis is a
frequent complication and more frequent in males.