Progressive frontal intraosseous lipoma: Detection of the mosaic AKT1 variant discloses Proteus syndrome.

Proteus syndrome is a very rare disorder with progressive, asymmetrical, and disproportionate overgrowth of body parts with a highly variable phenotype. It is associated with mosaicism for the recurrent heterozygous somatic gain-of-function variant c.49G>A (p.Glu17Lys) in the protein kinase AKT1. We report on a girl with a progressive intraosseous lipoma of the frontal bone and additional, nonspecific features including mild developmental delay, strabism, and a limbal dermoid of the left eye. She did not fulfill the criteria for a clinical diagnosis of Proteus syndrome. However, mutation analysis of AKT1 in a lipoma biopsy revealed this specific activating variant. Several cases of progressive intraosseous lipoma of the frontal bone have been reported in the literature. Only in two of these observations, a tentative diagnosis of Proteus syndrome was made, based on additional clinical features, although without molecular-genetic verification. We conclude that oligosymptomatic Proteus syndrome should be considered in progressive intraosseous lipoma, as recognition of this diagnosis has relevant implications for genetic counseling and opens novel treatment options with AKT1 inhibitors rather than surgical procedures.

Late-onset Proteus syndrome with cerebriform connective tissue nevus and subsequent development of intraductal papilloma.

Proteus syndrome (PS) is a rare segmental overgrowth disorder caused by a mosaic activating variant in AKT1. The features of PS are often not present at birth but develop during the first few years of life. We describe a 55-year-old female, whose first symptom of overgrowth, a cerebriform connective tissue nevus, occurred at 19 years of age. We report the identification of the AKT1 c.49G > A p.(Glu17Lys) variant in this progressive lesion, the bony overgrowth, and recurrence after surgical intervention. In the sixth decade of life, this individual developed intraductal papillomas within her right breast which were confirmed to contain the same activating AKT1 variant as the connective tissue nevus. While similar neoplasms have been described in an individual with Proteus syndrome, none has been evaluated for the presence of the AKT1 variant. The tumor also contained two likely pathogenic variants in PIK3R1, c.1392_1403dupTAGATTATATGA p.(Asp464_Tyr467dup) and c.1728_1730delGAG p.(Arg577del). The finding of additional genetic variation putatively affecting the PI3K/AKT pathway in the neoplastic tissue may provide preliminary evidence of a molecular mechanism for tumorigenesis in PS. The late onset of symptoms and molecular characterization of the breast tumor expand the clinical spectrum of this rare disorder.

Proteus syndrome caused by novel somatic AKT1 duplication.

Proteus syndrome (PS) is a rare overgrowth disorder that presents with asymmetrical growth of the bone and fat tissues following a mosaic pattern mutation. The estimated worldwide incidence is approximately one in one million live births. Proteus syndrome causes disfigurement and psychological impact through its effects on somatic tissue. Due to its rarity and diversity of tissues involved, it represents a significant challenge to caregivers and multidisciplinary medical teams. Here, we report a Saudi girl, with a large left cervical mass discovered antenatally. This mass was identified as a growing cystic hygroma, and she had features of overgrowth and hemangiomas. Whole exome sequencing was negative from the blood lymphocytes and affected tissue sample.  However, deletion duplication analysis from tissue shows a novel mosaic somatic mutation of the AKT1 gene. Somatic mutation remains an obstacle, and the geneticist has an essential role in its management, providing an established genetic diagnosis, prognosis, and family counselling.

Pathogenic postzygotic mosaicism in the tyrosine receptor kinase pathway: potential unidentified human disease hidden away in a few cells.

Mutations occurring during embryonic development affect only a subset of cells resulting in two or more distinct cell populations that are present at different levels, also known as postzygotic mosaicism (PZM). Although PZM is a common biological phenomenon, it is often overlooked as a source of disease due to the challenges associated with its detection and characterization, especially for very low-frequency variants. Moreover, PZM can cause a different phenotype compared to constitutional mutations. Especially, lethal mutations in receptor tyrosine kinase (RTK) pathway genes, which exist only in a mosaic state, can have completely new clinical manifestations and can look very different from the associated monogenic disorder. However, some key questions are still not addressed, such as the level of mosaicism resulting in a pathogenic phenotype and how the clinical outcome changes with the development and age. Addressing these questions is not trivial as we require methods with the sensitivity to capture some of these variants hidden away in very few cells. Recent ultra-accurate deep-sequencing approaches can now identify these low-level mosaics and will be central to understand systemic and local effects of mosaicism in the RTK pathway. The main focus of this review is to highlight the importance of low-level mosaics and the need to include their detection in studies of genomic variation associated with disease.

Overgrowth syndromes and new therapies.

Overgrowth syndromes represent a diverse group of disorders with overlapping features. Interdisciplinary management by a team of experts in vascular anomalies is crucial for establishing the correct diagnosis and optimizing outcomes for these patients. Unique management considerations include increased risk for thrombosis and in some cases, cancer. In recent years, research has demonstrated that these disorders are primarily caused by somatic mutations in growth pathways, particularly the PI3K-mTOR pathway. This improved understanding had led to promising new therapies for this group of patients.

Ubiquitous expression of Akt1 p.(E17K) results in vascular defects and embryonic lethality in mice.

Proteus syndrome is a progressive overgrowth disorder with vascular malformations caused by mosaic expression of the AKT1 c.49G > A, p.(E17K) activating variant which was predicted to cause lethality if expressed ubiquitously. To test that hypothesis, we used the ACTB-Cre gene to activate a conditional Akt1 p.(E17K) allele in the mouse. No offspring that was heterozygous for both Cre and the conditional allele (ßA-Akt1WT/flx) was viable. Fewer than expected numbers of ßA-Akt1WT/flx embryos were seen beginning at E11.5, but a few survived until E17.5. The phenotype ranged from mild to severe, but generally ßA-Akt1WT/flx embryos had fewer visible blood vessels and more hemorrhages than their wild-type littermates, which was suggestive of a vascular abnormality. Examination of E13.5 limb skin showed a primitive capillary network with increased branching complexity and abnormal patterning compared with wild-type skin. By E15.5, wild-type skin had undergone angiogenesis and formed a hierarchical network of remodeled vessels, whereas in ßA-Akt1WT/flx embryos, the capillary network failed to remodel. Mural cell coverage of the blood vessels was also reduced in ßA-Akt1WT/flx skin compared with that of wild type. Restricting expression of Akt1E17K to endothelial, cardiac or smooth muscle cells resulted in viable offspring and remodeled vasculature and did not recapitulate the ßA-Akt1WT/flx phenotype. We conclude that ubiquitous expression of Akt1E17K suppresses remodeling and inhibits the formation of a normal skin vasculature. We postulate that this failure prevents proper circulation necessary to support the growing embryo and that it is the result of interactions of multiple cell types with increased AKT signaling.

Pharmacodynamic Study of Miransertib in Individuals with Proteus Syndrome.

Proteus syndrome is a life-threatening segmental overgrowth syndrome caused by a mosaic gain-of-function AKT1 variant. There are no effective treatments for Proteus syndrome. Miransertib is an AKT1 inhibitor that, prior to this study, has been evaluated only in adult oncology trials. We designed a non-randomized, phase 0/1 pilot study of miransertib in adults and children with Proteus syndrome to identify an appropriate dosage starting point for a future efficacy trial using a pharmacodynamic endpoint. The primary endpoint was a 50% reduction in the tissue levels of AKT phosphorylation from biopsies in affected individuals. We also evaluated secondary efficacy endpoints. We found that a dose of 5 mg/m2/day (1/7 the typical dose used in oncology) led to a 50% reduction in phosphorylated AKT (pAKT) in affected tissues from five of six individuals. This dose was well tolerated. Two of the six efficacy endpoints (secondary objectives) suggested that this agent may be efficacious. We observed a decrease in a cerebriform connective tissue nevus and a reduction in pain in children. We conclude that 5 mg/m2/day of miransertib is an appropriate starting point for future efficacy trials and that this agent shows promise of therapeutic efficacy in children with Proteus syndrome.

Soft-tissue vascular malformations and tumors. Part 2: low-flow lesions. / Malformaciones vasculares y tumores de partes blandas. Parte 2: lesiones de bajo flujo.

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Due to a lack of a complete understanding of the origin and histopathology of such lesions, this field has been traditionally obscured by the use of an unclear nomenclature. Knowledge of the classification and clinical and imaging characteristics of this group of lesions is paramount when managing these patients. The objective of this series of two articles is to review the current classification of vascular anomalies, to describe the role of imaging in their diagnosis, to summarize their distinctive histopathologic, clinical and imaging features, and to discuss the treatment options. High-flow lesions were discussed in the first article of this series. In this second article, we will focus on low-flow lesions, including complex syndromes with associated low-flow malformations.

Severe gynaecological involvement in Proteus Syndrome.

Proteus Syndrome is a rare complex overgrowth syndrome. We report a young female patient with Proteus Syndrome due to AKT1 mutation c.49G > A (p.Glu17Lys), presenting with a severe gynaecological involvement which necessitated a complete hysterectomy and a left adnexectomy. Cases of gynecological involvements in Proteus Syndrome are rare, not well known by physicians while they can be potentially severe.

Epidermal Nevi and Related Syndromes -- Part 1: Keratinocytic Nevi. / Nevus epidérmicos y síndromes relacionados. Parte 1: nevus queratinocíticos.

Epidermal nevi are hamartomatous lesions derived from the epidermis and/or adnexal structures of the skin; they have traditionally been classified according to their morphology. New variants have been described in recent years and advances in genetics have contributed to better characterization of these lesions and an improved understanding of their relationship with certain extracutaneous manifestations. In the first part of this review article, we will look at nevi derived specifically from the epidermis and associated syndromes.

Redundant plantar skin folds.

A 46-year-old female patient presented with photosensitivity, symmetric arthritis, episodic plantar pain and strikingly redundant plantar skin folds, likely due to lipoatrophy after recurrent episodes of plantar panniculitis. In this context, leukopenia with lymphopenia, thrombocytopenia and positive antinuclear antibodies were revelatory for systemic lupus erythematosus. However, a small cerebriform plantar collagenoma, along with discrete dysmorphic features with downslanting palpebral fissures and mild right ptosis, second and third syndactyly and a larger first right toe since childhood, and early-onset bilateral ovarian cystadenoma, suggested a minimal Proteus syndrome. Genetic confirmation could not be performed. As adipose tissue dysregulation may be a feature of Proteus syndrome, the possible mechanisms leading to localized lipoatrophy in this setting are discussed. This case enlights intriguing links between adipogenesis, inflammation and dysmorphology. From a practical point of view, finding and treating an over-imposed inflammation could help limit damage in a hamartomatous syndrome.

Lack of mutation-histopathology correlation in a patient with Proteus syndrome.

Proteus syndrome (PS) is characterized by progressive, disproportionate, segmental overgrowth, and tumor susceptibility caused by a somatic mosaic AKT1 activating mutation. Each individual has unique manifestations making this disorder extremely heterogeneous. We correlated three variables in 38 tissue samples from a patient who died with PS: the gross affection status, the microscopic affection status, and the mutation level. The AKT1 mutation was measured using a PCR-based RFLP assay. Thirteen samples were grossly normal; six had detectable mutation (2-29%) although four of these six were histopathologically normal. Of the seven grossly normal samples that had no mutation, only four were histologically normal. The mutation level in the grossly abnormal samples was 3-35% and all but the right and left kidneys, skull, and left knee bone, with mutation levels of 19%, 15%, 26%, and 17%, respectively, had abnormal histopathology. The highest mutation level was in a toe bone sample whereas the lowest levels were in the soft tissue surrounding that toe, and an omental fat nodule. We also show here that PS overgrowth can be caused by cellular proliferation or by extracellular matrix expansion. Additionally, papillary thyroid carcinoma was identified, a tumor not previously associated with PS. We conclude that gross pathology and histopathology correlate poorly with mutation levels in PS, that overgrowth can be mediated by cellular proliferation or extracellular matrix expansion, and that papillary thyroid carcinoma is part of the tumor susceptibility of PS. New methods need to be developed to facilitate genotype-phenotype correlation in mosaic disorders. © 2016 Wiley Periodicals, Inc.

Clinical and historical aspects of the Elephant Man: exploring the facts and the myths.

Joseph Merrick, the Elephant Man, presented to the Royal London Hospital in 1884 with an obscure condition that puzzled his contemporaries, and fascinates clinicians to this day. Throughout the 1900s, a number of theories were advanced to explain the numerous growths that covered his body: neurofibromatosis, Proteus syndrome, and a combination of childhood injury, fibrous dysplasia, and pyarthrosis. The debate continued throughout the 20th century without resolution. Today, new consensus on the genetic and clinical diagnosis of neurofibromatosis and Proteus syndrome has allowed advancements in the Elephant Man's diagnosis. Using recent clinical diagnostic criteria it is now possible to conclude that Joseph Merrick was in all likelihood suffering from Proteus syndrome. Nevertheless, details of his genotype remain unknown. Obtaining intact DNA from the Elephant Man's skeleton is challenging, yet it is possible that sequencing Merrick's genome could provide genetic confirmation of his clinical diagnosis, and shed light on the process of tumourigenesis.

Myocardial fat overgrowth in Proteus syndrome.

Proteus syndrome (PS) is a rare, mosaic disorder with asymmetric and distorting overgrowth of the skeletal system, skin, and adipose tissues. Cardiac abnormalities are rare in this syndrome and only two prior cases have been reported. Many patients with PS followed at our institution underwent transthoracic echocardiograms for preoperative evaluation or as work-up for associated pulmonary disease. Some were noted to have prominent, focal echodense areas in the myocardium. We further investigated cardiac findings in a cohort of children and adult patients with PS. Patients with abnormal echocardiograms were referred for cardiac magnetic resonance imaging, Holter monitoring, and exercise treadmill testing. Twenty children and adults with PS, age 24 months to 50 years old, underwent transthoracic echocardiograms. Seven patients (35%) had focal bright echodense areas within the myocardium suggesting fatty infiltration. The majority of patients had significant involvement of the interventricular septum. The cardiac characteristics of all patients with fatty infiltration on transthoracic echocardiograms were compared to Proteus patients without these findings. There were no significant differences in chamber sizes, mass, systolic or diastolic function. No increased risk of conduction defects or arrhythmias was found. This study shows that abnormal fat overgrowth is a common finding in the myocardium in patients with Proteus syndrome; however, it is not associated with functional derangements or arrhythmias. Further evaluation of a larger number of Proteus patients is needed in order to determine the frequency and prognosis of cardiac involvement. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Síndrome de Proteus: relato de casos / Proteus Syndrome: case reports

INTRODUÇÃO: A síndrome de Proteus é uma doença complexa e rara, classificada nos grupo das hamartoses. Foi primeiramente descrita em dois pacientes, em 1979, por Cohen e Hayden. Existe dificuldade no diagnóstico, sendo comum a confusão com síndromes de Klippel-Trenaunay-Weber, neurofibromatose ou Stuge-Weber. Apresentamos dois casos tratados no Serviço de Cirurgia Plástica e Reparadora da Universidade Federal do Paraná. MÉTODO: Paciente masculino (caso 1), que chegou ao serviço aos 6 anos de idade, tendo como principais apresentações lipomatoses e assimetrias. A segunda paciente (caso 2) deu entrada no serviço com 20 anos de idade e diagnóstico de síndrome de Klippel-Trenaunay-Weber, que posteriormente mostrou se tratar de síndrome de Proteus. CONCLUSÃO: A hipótese etiológica mais aceita para a doença é genética. Acredita-se que exista mosaicismo somático e que a doença seja letal no estado não mosaico. Morte prematura é bastante frequente. Entretanto, a sequela mais comum é a ocorrência de tumores incomuns. O cuidado dos pacientes portadores da síndrome é um desafio devido às suas consequências médicas e psicossociais.

INTRODUCTION: Proteus syndrome is a complex and rare disorder classified as a hamartomatous disease. It was first described in two patients in 1979, by Cohen and Hayden. Proteus syndrome is difficult to diagnose, and is often confused with Klippel-Trenaunay-Weber syndrome, neurofibromatosis, or Sturge-Weber syndrome. In this study we describe two patients who were treated at the Plastic and Reconstructive Surgery Service of the Federal University of Paraná. METHOD: A 6-year-old male patient (case 1) presented to the Service with lipomatosis and asymmetry, as the primary findings. A 20-year-old (case 2) was admitted to the Service with a diagnosis of Klippel-Trenaunay-Weber syndrome, which later was shown to be Proteus syndrome. CONCLUSION: The etiological hypothesis that is most accepted for this disease is genetic. It is believed that somatic mosaicism may occur during pathogenesis, which can be lethal in the mosaic state. Premature death is common. However, the most common sequelae are the occurrence of unusual tumors. The care of patients with this syndrome is a challenge due to medical and psychosocial consequences.

Proteus syndrome review: molecular, clinical, and pathologic features.

Proteus syndrome is caused by an activating AKT1 mutation (c.49G>A, p.Glu17Lys). Many variable features are possible in this mosaic disorder, including: (i) disproportionate, asymmetric, and distorting overgrowth; (ii) bone abnormalities different from those observed in other disorders; (iii) a characteristic cerebriform connective tissue nevus made up of highly collagenized connective tissue; (iv) epidermal nevi in early life, consisting of acanthosis and hyperkeratosis; (v) vascular malformations of the capillary, venous, or lymphatic types; (vi) dysregulated adipose tissue including lipomas, lipohypoplasia, fatty overgrowth, and localized fat deposits; (vii) other unusual features, including bullous lung alterations; specific neoplasms; a facial phenotype associated with intellectual disability and/or seizures, and/or brain malformations; and (viii) deep vein thrombosis, resulting in premature death. Concluding remarks address diagnostic criteria, natural history, management, psychosocial issues, and differential diagnosis.

Proteus syndrome revealing itself after the treatment of a bilateral subdural haematoma.

INTRODUCTION: Hypertrophy of the calvarium has different aetiologies, among them the rare Proteus syndrome. CASE REPORT: We report here the case of a young girl initially treated for relapsing right then left large chronic subdural haematoma, who progressively developed craniofacial hypertrophy consistent with the diagnosis of Proteus syndrome. Calvarium hypertrophy was shaved and remodelled combining midface advancement, essentially for cosmetic purposes. During the first calvarium remodelling, important bleeding of the bone required large volume of blood replacement. Haemostasis workup revealed platelets aggregation anomalies. Bleeding issues during subsequent surgeries were controlled with tranexamic acid and desmopressin acetate. DISCUSSION: Other manifestations of Proteus syndrome, such as a right hypertrophy of the face with hypoplasia of its middle third, a pigmented epidermal nevus and asymmetric limbs and scoliosis, appeared progressively over time. Blood and fibroblast phosphatase and tensin homolog mutation was not found. CONCLUSION: Literature review of operated patients with Proteus syndrome did not reveal an association with platelets anomalies. A complete haemostasis workup following this unexpected haemorrhagic complication is recommended for this rare pathology.