Median nerve compression in Proteus syndrome

Proteus syndrome with sciatic nerve fibrolipomatous hamartoma: an uncommon finding in a rare disease: report of two cases with literature review

Proteus syndrome is an extremely rare condition, characterized by progressive asymmetric overgrowth of multiple body tissues. Here, we present two cases of Proteus syndrome demonstrating typical clinical and radiological features of Proteus syndrome, in addition to an uncommon fibrolipomatous hamartoma of the sciatic nerve. The first case is a 5-year-old girl who presented with seizures. The patient showed facial dysmorphic features, left head enlargement, kyphoscoliosis, asymmetric overgrowth of the right lower limb, right foot drop, and cribriform connective tissue nevi on the right palm and the right sole. Radiological examinations demonstrated left calvarial hyperostosis, dysplasia of the left cerebral hemisphere, dysregulation of the subcutaneous adipose fat of the body, kyphoscoliosis, and lipoma of the filum terminale. CT of both thighs showed asymmetric soft tissue overgrowth of the right thigh, associated with diffuse enlargement and fatty infiltration of the right sciatic nerve starting from the upper thigh, down to its bifurcation into the tibial and common peroneal nerves. The second case is an 18-year-old girl who presented with left conductive deafness. The patient showed facial dysmorphic features, right head enlargement, asymmetric overgrowth of the right upper limb, kyphoscoliosis, left foot drop, and cribriform connective tissue nevi on the nose and the left foot. Radiological examinations demonstrated right calvarial hyperostosis, left external auditory canal hyperostosis and stenosis, and kyphoscoliosis. CT and MRI of both thighs showed diffuse enlargement of the left sciatic nerve starting from the upper thigh down to the mid-thigh and showing interfascicular adipose tissue proliferation, giving the typical features of nerve lipomatosis.

Reassessment of the Proteus syndrome literature: application of diagnostic criteria to published cases

The medical care of patients affected by rare disorders depends heavily on experiences garnered from prior cases, including those patients evaluated by the treating physician and those published in the medical literature. The utility of published cases is wholly dependent upon accurate diagnosis of those patients. In our experience, the rate of misdiagnosis in Proteus syndrome (PS) is high. Diagnostic criteria have been published, but these criteria have not been applied consistently and were published after many case reports appeared in the literature. We reviewed 205 cases of individuals reported to have PS in the literature and three of us independently applied the diagnostic criteria to these case reports. Our initial diagnostic congruence was 97.1% (199/205); the discrepancies in six cases were easily resolved. Only 97 (47.3%) of reported cases met the diagnostic criteria for PS; 80 cases (39%) clearly did not meet the criteria; and although 28 cases (13.7%) had features suggestive of PS, there were insufficient clinical data to make a diagnosis. Reported cases that met the PS criteria had a higher incidence of premature death, and other complications (scoliosis, megaspondyly, central nervous system abnormalities, tumors, otolaryngologic complications, pulmonary cystic malformations, dental and ophthalmogic complications) compared to those in the non-Proteus group. The cases that met the criteria were more often male, which has implications for hypotheses regarding the etiology and pathophysiology of PS. We also studied the attributes that led authors to conclude the reported patients had PS when we concluded they did not. We found that two of the diagnostic criteria (disproportionate overgrowth and connective tissue nevi) were often misinterpreted. In PS, the abnormal growth is asymmetric, distorting, relentless, and occurred at a faster rate compared to the rest of the body. Furthermore, PS was associated with irregular and disorganized bone, including hyperostoses, hyperproliferation of osteoid with variable calcification, calcified connective tissue, and elongation of long bones with abnormal thinning. In contrast, non-Proteus cases displayed overgrowth that was asymmetric but grew at a rate similar to the growth found in unaffected areas of the body. Also, the overgrowth in non-Proteus cases was associated with normal or enlarged bones together with ballooning of the overlying soft tissues. Taken together, these data show that (1) PS diagnostic criteria sort individuals with asymmetric overgrowth into distinct groups; (2) individuals with PS were more likely to have serious complications; (3) PS affects more males than females; and 4) the published diagnostic criteria are useful for clinical care and research. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148-7299/suppmat/index.html.

Principles for the surgical management of patients with Proteus syndrome and patients with overgrowth not meeting Proteus criteria

BACKGROUND

Proteus syndrome is a rare, sporadic disorder consisting of disproportionate overgrowth of multiple tissues, vascular malformations, and connective tissue or epidermal nevi. Patients with Proteus syndrome present with diverse and variable phenotypes because of the syndrome's mosaic pattern of distribution.

METHODS

Eighty patients with Proteus syndrome, satisfying published diagnostic criteria, and 51 patients with overgrowth not meeting Proteus criteria were identified from the literature. Three additional patients, one patient with Proteus syndrome and 2 patients with overgrowth, were treated at the author's institutions and are discussed in detail. All nonorthopedic and noncutaneous surgical interventions were reviewed.

RESULTS

Fourteen genitourinary, 9 gastrointestinal, and 5 otolaryngologic operations were performed on patients with Proteus syndrome. Six genitourinary, 5 gastrointestinal, and 2 otolaryngologic operations were performed on patients with overgrowth not meeting Proteus criteria. Eight patients with Proteus syndrome and 4 patients with overgrowth experienced thoracic manifestations, generally diffuse cystic pulmonary lesions, but only 1 of 12 underwent surgical treatment.

CONCLUSIONS

Patients with visceral manifestations of either Proteus syndrome or overgrowth not meeting Proteus criteria should be treated in a similar manner. Lesions involving the ovaries and testes, because of the high incidence of neoplasm, should be managed aggressively. Gastrointestinal and renal lesions may be managed conservatively with frequent follow-up to minimize abdominal explorations. All patients undergoing surgery should have a thorough preoperative assessment of their airway and pulmonary reserve because of the relatively high frequency of tonsillar hypertrophy and pulmonary cystic involvement.