Proteus syndrome: emphasis on the pulmonary manifestations

Quantification of Proteus syndrome-associated lung disease

BACKGROUND

Proteus syndrome is an ultra-rare mosaic overgrowth disorder. Individuals with Proteus syndrome can develop emphysematous and cystic changes of the lung that may lead to progressive respiratory symptoms and require surgical intervention. This retrospective study seeks to quantify the radiographic features of Proteus syndrome-associated lung disease using computed tomography (CT) of the chest. The first method derives a Cystic Lung Score (CLS) by using a computer-aided diagnostic tool to quantify the fraction of cystic involvement of the lung. The second method yields a Clinician Visual Score (CVS), an observer reported scale of severity based on multiple radiographic features. The aim of this study was to determine if these measurements are associated with clinical symptoms, pulmonary function test (PFT) measurements, and if they may be used to assess progression of pulmonary disease.

RESULTS

One hundred and thirteen imaging studies from 44 individuals with Proteus syndrome were included. Dyspnea and oxygen use were each associated with higher CLS (p = 0.001 and < 0.001, respectively) and higher CVS (p < 0.001 and < 0.001). Decreases in percent predicted FVC, FEV1, and DLCO each correlated with increased CLS and CVS. The annual increase of CLS in children, 5.6, was significantly greater than in adults, 1.6. (p = 0.03). The annual increase in CVS in children, 0.4, was similar to adults, 0.2 (p = 0.36).

CONCLUSIONS

Proteus syndrome-associated lung disease is progressive. The rate of cystic progression is increased in children. Increased scores in CLS and CVS were associated with clinical symptoms and decreased pulmonary function. Both methods were able to detect change over time and were associated with clinically meaningful outcomes which may enable their use in interventional studies.

Cardiothoracic imaging findings of Proteus syndrome

In this work, we sought to delineate the prevalence of cardiothoracic imaging findings of Proteus syndrome in a large cohort at our institution. Of 53 individuals with a confirmed diagnosis of Proteus syndrome at our institution from 10/2001 to 10/2019, 38 individuals (men, n = 23; average age = 24 years) underwent cardiothoracic imaging (routine chest CT, CT pulmonary angiography and/or cardiac MRI). All studies were retrospectively and independently reviewed by two fellowship-trained cardiothoracic readers. Disagreements were resolved by consensus. Differences between variables were analyzed via parametric and nonparametric tests based on the normality of the distribution. The cardiothoracic findings of Proteus syndrome were diverse, but several were much more common and included: scoliosis from bony overgrowth (94%), pulmonary venous dilation (62%), band-like areas of lung scarring (56%), and hyperlucent lung parenchyma (50%). In addition, of 20 individuals who underwent cardiac MRI, 9/20 (45%) had intramyocardial fat, mostly involving the endocardial surface of the left ventricular septal wall. There was no statistically significant difference among the functional cardiac parameters between individuals with and without intramyocardial fat. Only one individual with intramyocardial fat had mildly decreased function (LVEF = 53%), while all others had normal ejection fraction.

Imaging of the rare cystic lung diseases

When discussing cystic lung diseases, a certain group of diseases tends to receive the majority of attention. Other less frequently discussed cystic lung diseases are also important causes of morbidity in patients. Etiologies include genetic syndromes, lymphoproliferative diseases, infections, exogenous exposures, and a developmental abnormality. This review article focuses on the clinical and imaging features of these other cystic lung diseases.

Clinical report: one year of treatment of Proteus syndrome with miransertib (ARQ 092)

A 20-yr-old man with Proteus syndrome (PS) and somatic mosaicism of the AKT1 c.49G > A p.(E17K) variant had asymmetric overgrowth of the right frontal and facial bones, asymmetric spinal overgrowth with thoracolumbar scoliosis, dilatation of the inferior vena cava, testicular cystadenoma, bilateral knee deformities, macrodactyly, and apparent intellectual disability. Miransertib (ARQ 092) is an oral, allosteric, selective pan-AKT inhibitor initially developed for cancer therapeutics, now being evaluated for the treatment of PS. After baseline evaluation, the patient started unblinded treatment of 10 mg oral miransertib daily (∼5 mg/m²/day), escalated to 30 mg daily (∼15 mg/m²/day), and then to 50 mg daily (∼25 mg/m²/day) after 3 mo of treatment. Adverse events included dry mouth, one episode of gingivostomatitis, and loose, painful dentition due to preexisting periodontal disease, all of which resolved spontaneously. After 11 mo of treatment, the patient reported improved general well-being, increased mobility of the ankle, spine, and hands, a subjective decrease in size of the right facial bone overgrowth, and reduced areas of cerebriform connective tissue nevi on the soles. Whole-body MRI findings were stable without apparent disease progression. We conclude that 1 yr of treatment with miransertib was beneficial in this case.

Cystic Lung Diseases: Algorithmic Approach

Cysts are commonly seen on CT scans of the lungs, and diagnosis can be challenging. Clinical and radiographic features combined with a multidisciplinary approach may help differentiate among various disease entities, allowing correct diagnosis. It is important to distinguish cysts from cavities because they each have distinct etiologies and associated clinical disorders. Conditions such as emphysema, and cystic bronchiectasis may also mimic cystic disease. A simplified classification of cysts is proposed. Cysts can occur in greater profusion in the subpleural areas, when they typically represent paraseptal emphysema, bullae, or honeycombing. Cysts that are present in the lung parenchyma but away from subpleural areas may be present without any other abnormalities on high-resolution CT scans. These are further categorized into solitary or multifocal/diffuse cysts. Solitary cysts may be incidentally discovered and may be an age related phenomenon or may be a remnant of prior trauma or infection. Multifocal/diffuse cysts can occur with lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, tracheobronchial papillomatosis, or primary and metastatic cancers. Multifocal/diffuse cysts may be associated with nodules (lymphoid interstitial pneumonia, light-chain deposition disease, amyloidosis, and Langerhans cell histiocytosis) or with ground-glass opacities (Pneumocystis jirovecii pneumonia and desquamative interstitial pneumonia). Using the results of the high-resolution CT scans as a starting point, and incorporating the patient's clinical history, physical examination, and laboratory findings, is likely to narrow the differential diagnosis of cystic lesions considerably.

Diffuse Cystic Lung Disease. Part II

The diffuse cystic lung diseases have a broad differential diagnosis. A wide variety of pathophysiological processes spanning the spectrum from airway obstruction to lung remodeling can lead to multifocal cyst development in the lung. Although lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis are perhaps more frequently seen in the clinic, disorders such as Birt-Hogg-Dubé syndrome, lymphocytic interstitial pneumonia, follicular bronchiolitis, and light-chain deposition disease are increasingly being recognized. Obtaining an accurate diagnosis can be challenging, and management approaches are highly disease dependent. Unique imaging features, genetic tests, serum studies, and clinical features provide invaluable clues that help clinicians distinguish among the various etiologies, but biopsy is often required for definitive diagnosis. In part II of this review, we present an overview of the diffuse cystic lung diseases caused by lymphoproliferative disorders, genetic mutations, or aberrant lung development and provide an approach to aid in their diagnosis and management.

Cystic lung lesions in newborns and young children: differential considerations and imaging

Numerous diverse entities produce cystic lung changes in neonates and young children. This review provides an evidence-based, age-appropriate, differential diagnostic framework to use when confronted with pulmonary cystic changes. The categories of diseases that have been discussed include congenital cystic bronchopulmonary malformations, neoplastic conditions, infections, collagen or soft tissue abnormalities, and mimics of cystic lung disease. An understanding of the pathophysiology, imaging appearance, and demographics of these entities is essential in guiding optimal care. Important educational points include differentiating bronchopulmonary malformations from neoplasms and the management and surveillance of lung cysts in young children.

[The Proteus syndrome: a rare cause of pulmonary emphysema]

INTRODUCTION

The Proteus syndrome is a rare genetic disease which is characterized by the overgrowth of tissues, especially bone, connective and adipose tissue. This condition is related to a somatic mosaic activating mutation in the AKT1 oncogene.

CASE REPORT

We report the case of a 25-year-old man, diagnosed with the Proteus syndrome at the age of 6 months. He exhibited an asymmetric overgrowth of the extremities leading to bilateral amputation of the legs at the age of 10 years. He was hospitalized for acute respiratory failure due to a bronchopulmonary infection. Severe bullous pulmonary emphysema, predominantly on the left, with mediastinal deviation, was diagnosed. The patient recovered with antibiotics. An assessment 2 months later revealed mild hypoxaemia (PaO2=75 mmHg) and severe airflow limitation (FEV1=1260 mL [28% th.], FEV1/V C=69%) with hyperinflation (TLC=7840 mL [107% th.], RV=6010 mL [253% th.]).

CONCLUSION

The Proteus syndrome is a very rare cause of pulmonary emphysema. The pathophysiology of emphysema in this syndrome is unknown. It can be hypothesized that the development of pulmonary cysts leading to emphysema may share the same AKT1 activation pathway with lymphangioleiomyomatosis.

Pulmonary manifestations in Proteus syndrome: pulmonary varicosities and bullous lung disease

We report on two patients with Proteus syndrome (PS), with emphasis on its pulmonary manifestations. The first patient was a 6-year-old girl diagnosed with PS at 5 years of age. The pulmonary abnormalities first observed at age 3 years and included streaky densities with accentuated vascular markings detected by chest radiography. The patient had persistent abnormalities on follow-up chest radiographs. Chest computed tomography (CT) scans showed diffuse pulmonary venous dilatations. The second patient was a 10-year-old boy diagnosed with PS at age 4 years. Chest radiography and CT scans showed patchy and streaky densities intermixed with small bullae, which were interpreted as pneumonia with post-inflammatory pneumatoceles. The patient developed diffuse enlargement of air spaces of the lungs at age 10 years with severe respiratory compromise. Although pulmonary manifestations in PS are uncommon, recognition of pulmonary vein malformation and the presentation of enlarged air spaces in the lungs at an earlier age are important for accurate diagnosis. The plain radiograph findings of accentuated vascular markings seen in patients with PS may appear similar to interstitial or chronic pneumonia. This report emphasizes the features of lung involvement in children with PS and suggests that specific attention be paid to pulmonary manifestations using chest CT scans. © 2011 Wiley-Liss, Inc.

The group of epidermal nevus syndromes Part I. Well defined phenotypes

The epidermal nevus syndromes represent a group of distinct disorders that can be distinguished by the type of associated epidermal nevus and by the criterion of presence or absence of heritability. Well defined syndromes characterized by organoid epidermal nevi include Schimmelpenning syndrome, phacomatosis pigmentokeratotica, nevus comedonicus syndrome, angora hair nevus syndrome, and Becker nevus syndrome. The molecular basis of these disorders has so far not been identified. By contrast, the group of syndromes characterized by keratinocytic nevi comprises three phenotypes with a known molecular etiology in the form of CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, type 2 segmental Cowden disease, and fibroblast growth factor receptor 3 epidermal nevus syndrome (García-Hafner-Happle syndrome), whereas Proteus syndrome is still of unknown origin. From this overview, it is clear that a specific type of these disorders cannot be classified by the name "epidermal nevus syndrome" nor by the terms "organoid nevus syndrome" or "keratinocytic nevus syndrome."

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to distinguish nine different epidermal nevus syndromes by their characteristic features, understand the practical significance of avoiding terms like "epidermal nevus syndrome" or "keratinocytic nevus syndrome" to define any specific entity within this group of disorders, and differentiate between nonhereditary traits and those bearing a genetic risk because of either Mendelian or non-Mendelian inheritance.

Proteus Syndrome: A Case Report

Proteus syndrome is a rare, sporadically occurring hamartomatous disorder with complex multisystem involvement and wide clinical variability. Clinical characteristics include craniofacial abnormalities; asymmetrical overgrowth of the trunk, limbs, and digits; lipomas; and vascular malformations. Cystic lung disease is noted in approximately 10 per cent of patients. These cystic malformations may lead to cystic pulmonary emphysema, which may cause significant morbidity for the patient. We describe the case of a 27-year-old woman with known Proteus syndrome who developed acute on chronic respiratory failure. Subsequent CT scan of the chest was significant for extensive bullous disease with nearly complete replacement of the right lung tissue. Our operative management and the patient's clinical course are described.

Proteus syndrome: high-resolution CT and CT pulmonary densitovolumetry findings

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.

Perioperative respiratory complications caused by cystic lung malformation in Proteus syndrome

A 7-year-old girl with Proteus syndrome, complicated with severe kyphoscoliosis and cystic lung malformation, developed respiratory complications during and after posterior spinal fusion under general anesthesia. We speculated that low oxygenation while in the prone position contributed to ventilation perfusion mismatch owing to the cystic lung malformation that existed predominantly in the right lung, and that postoperative respiratory failure was caused by initially increased bronchial mucous secretions and secondary persistent bacterial pneumonia. Cystic lung malformation rather than reduced respiratory function, although both can be a cause of mucous clearance impairment, should be considered as one of the predictive factors for perioperative respiratory failure in Proteus syndrome.

Proteus Syndrome with Multiple Genitourinary Abnormalities

Proteus syndrome is a rare hamartomatous disorder comprising a broad spectrum of congenital malformations and overgrowth of multiple tissues. Some rare urogenital malformations have been reported before. This case is unique for the presence of multiple genitourinary anomalies including retroperitoneal cystic mass, intra-abdominal testicle with hematoma and ureterovesical stricture apart from common clinic findings of proteus syndrome.

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.

Vascular low-flow malformations in children: current concepts for classification, diagnosis and therapy

Congenital vascular malformations (CVM) are made of dysplastic vessels with no cellular proliferation. Low- or slow-flow malformations (LFM) consist predominantly of venous and/or lymphatic vessels. Correct terminology is necessary for differentiating vascular malformations from tumours such as haemangiomas, in order to prevent ineffective or even adverse therapy. The role of the radiologist in the management of patients is two-fold: making the diagnosis with the use of ultrasound and magnetic resonance imaging, and performing sclerotherapy, which is the treatment of choice. Prior to sclerotherapy, percutaneous phlebography is necessary to visualize the dynamic situation inside the lesion and the flow into the adjacent vascular system. The double-needle technique is a useful therapy option reducing the risk of embolisation of the sclerosing agent. Large lesions might need subsequent surgical treatment. A multidisciplinary approach is substantial for optimal patient management.

Anesthesia for proteus syndrome

Proteus syndrome is a complex disorder comprising malformations and overgrowth of multiple tissues. The disorder is highly variable affecting tissues in a mosaic pattern. A 2-year-old boy with Proteus syndrome, with epidermal verrucal naevus, hyperplastic lesions of connective tissue, hyperostosis, overgrowth of tubular bones, bilateral inguinal hernia, and juvenile intestinal polyposis was scheduled for vertebral magnetic resonance imaging (MRI) for further evaluation of malignancies. In addition to the pathological findings of this syndrome, potential complications such as difficult intubation, pulmonary hypertension, and pulmonary thromboembolism necessitate a careful preoperative and anesthetic preparation. MRI was performed under general anesthesia. There were no anesthetic complications. There are few previous reports on anesthesia in a patient with Proteus syndrome.

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.

Sudden death caused by pulmonary thromboembolism in Proteus syndrome

We report 3 patients with Proteus syndrome (PS) who died suddenly from pulmonary embolism (PE). The first patient was a male diagnosed with PS at 12 years who had varicose veins, portal vein thrombosis, right iliac vein occlusion and recurrent PE. At age 25 years, he was admitted to the hospital with a severe headache. Despite therapeutic doses of warfarin, investigations for an acute episode of breathlessness showed PE and he was unable to be resuscitated. The second case was a 9-year-old male with PS who collapsed at home and could not be revived. Autopsy revealed that the cause of death was a PE associated with thrombosis of the deep veins (DVT). The third patient was a 17-year-old female undergoing inpatient treatment for sinusitis when she unexpectedly arrested. She could not be revived and a full autopsy revealed a large PE with no identified DVT. We conclude that PE is a serious complication of PS and recommend vigilance concerning the signs and symptoms of thrombosis and PE in individuals with PS, including children. Aggressive evaluation and treatment should be considered urgently in patients with PS and signs or symptoms of DVT.

Proteus syndrome: clinical and surgical aspects

The authors report a new case of Proteus syndrome with delayed diagnosis and they discuss the place of surgery in this syndrome.

Ocular manifestations in Proteus syndrome

We report on the ocular manifestations of a Proteus syndrome patient. Several of the manifestations are due to severe maldevelopment and malfunction of the neuroretina including strabismus, nystagmus, high myopia, and retinal pigmentary abnormalities. In reviewing the literature, strabismus and epibulbar tumors were recorded most commonly. Some articles about presumed Proteus syndrome are spurious; these have not been included here. Also, because of anecdotal and nonsystematic study of the eye and because of the ascertainment bias inherent in literature reports, numbers of cases of each ocular manifestation have not been tabulated.

Proteus syndrome: diagnostic criteria, differential diagnosis, and patient evaluation

Proteus syndrome is a complex disorder comprising malformations and overgrowth of multiple tissues. The disorder is highly variable and appears to affect patients in a mosaic manner. This intrinsic variability has led to diagnostic confusion associated with a dearth of longitudinal data on the natural history of Proteus syndrome. To clarify some of these issues, a workshop on Proteus syndrome was held in March 1998 at the National Institutes of Health, and participants developed recommendations for diagnostic criteria, differential diagnosis, and guidelines for the evaluation of patients. This is a review of those recommendations.

Pathology of lipomatous lesions in Proteus syndrome

Proteus syndrome is an extremely rare, complex hamartomatous disorder with markedly variable clinical expression. We present a case of Proteus syndrome with multiple disfiguring soft tissue masses that were present since early childhood. The lesions involved predominantly the right side of the body and included scoliosis, macrodactyly, and limited hyperostosis in the right foot. There was no evidence of cranial or skin lesions. The patient underwent multiple resections of soft tissue masses, including an amputation of the right foot because of severe gait disturbance. All specimens exhibited lipomatous lesions that were probably hamartomatous rather than neoplastic. She carried a diagnosis of neurofibromatosis for more than a decade, but a re-evaluation of clinical features and pathological findings prompted the diagnosis of Proteus syndrome. We believe that a more informed evaluation of the pathology material may help to identify this rare entity.

Proteus syndrome: new findings in seven patients

Seven children with Proteus syndrome (PS) are reported. The majority of clinical findings coincide with what is reported in the literature. New findings were blue sclerae, telecanthus, epiblepharon, endotropy, hemimegaly of the optic nerve, occipital dysmyelination and compression of the corpus callosum, craneosynostosis, decalcification and thinning of the cortical layer of long bones, and talipes equinus. The clinical findings, possible etiology, differential diagnosis, and treatment of PS are discussed.