Topical rapamycin as a treatment for fibrofolliculomas in Birt-Hogg-Dubé syndrome: a double-blind placebo-controlled randomized split-face trial.

BACKGROUND: Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disorder characterised by the occurrence of benign, mostly facial, skin tumours called fibrofolliculomas, multiple lung cysts, spontaneous pneumothorax and an increased renal cancer risk. Current treatments for fibrofolliculomas have high rates of recurrence and carry a risk of complications. It would be desirable to have a treatment that could prevent fibrofolliculomas from growing. Animal models of BHD have previously shown deregulation of mammalian target of rapamycin (mTOR). Topical use of the mTOR inhibitor rapamycin is an effective treatment for the skin tumours (angiofibromas) in tuberous sclerosis complex, which is also characterised by mTOR deregulation. In this study we aimed to determine if topical rapamycin is also an effective treatment for fibrofolliculomas in BHD. METHODS: We performed a double blinded, randomised, facial left-right controlled trial of topical rapamycin 0.1% versus placebo in 19 BHD patients. Trial duration was 6 months. The primary outcome was cosmetic improvement as measured by doctors and patients. Changes in fibrofolliculoma number and size were also measured, as was occurrence of side effects. RESULTS: No change in cosmetic status of fibrofolliculomas was reported in the majority of cases for the rapamycin treated (79% by doctors, 53% by patients) as well as the placebo treated facial sides (both 74%). No significant differences between rapamycin and placebo treated facial halves were observed (p = 1.000 for doctors opinion, p = 0.344 for patients opinion). No significant difference in fibrofolliculoma number or change in size of the fibrofolliculomas was seen after 6 months. Side effects occurred more often after rapamycin treatment (68% of patients) than after placebo (58% of patients; p = 0.625). A burning sensation, erythema, itching and dryness were most frequently reported. CONCLUSIONS: This study provides no evidence that treatment of fibrofolliculomas with topical rapamycin in BHD results in cosmetic improvement. TRIAL REGISTRATION: ClinicalTrials.gov NCT00928798.

Hypertrophy in labial capillary malformations: clinical and pathological findings in 11 patients.

Hypertrophy in capillary malformation (CM) may be present at birth or manifest itself later in life. To gain insight into the pathology of hypertrophic CM, we investigated a series of 11 excisional biopsies of hypertrophic lips.All biopsies showed dilated thin-walled microvessels in the superficial dermis without a neural component. However, large multinodular conglomerates of thick-walled vessels with a substantial increase in nerve fibers were found in the deeper parts of the lesions. These veins extended deep into the facial musculature. Hypertrophy in CM is caused by venous malformation underlying the CM. So CM associated with hypertrophy should be considered as Capillary Venous malformations.

The persistent embryonic vein in Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a congenital malformation syndrome with prominent vascular anomalies. A persistent embryonic vein (PEV) may be located on the affected leg(s) of patients with KTS. Our understanding of PEVs of the legs is limited and their nomenclature is confusing. The objective of this study was to obtain further insight in the prevalence, nomenclature and etiology of PEVs of the legs in KTS and to propose a standardized description of anomalous leg veins in KTS. We investigated 70 KTS patients for the presence of PEVs (lateral marginal vein, LMV) of the legs by duplex ultrasonography. We performed histopathological analysis of a surgically excised PEV (LMV) of a typical KTS patient, and we conducted an extensive literature study. Duplex ultrasonography showed LMVs in 12/70 (17.1%) patients. The terms used to describe PEVs in the leg are quite variable, while indicating only two types: lateral marginal vein (LMV) and persistent sciatic vein (PSV). The histology of the excised LMV showed remarkable similarity with that of varicose veins found in the general population. In conclusion, the prevalence of LMVs in our KTS cohort is 17.1%. Two PEVs can be found in the legs and we propose nomenclature based on anatomical criteria, thereby using only the terms persistent lateral marginal vein and persistent sciatic vein, combined with the patency of the deep venous system. We hypothesize that PEVs are most likely caused by a genetic defect leading to abnormal venous pattern formation, which is further supported by our histopathological findings.

Phenotypic variability in a family with capillary malformations caused by a mutation in the RASA1 gene.

Hereditary capillary malformations are known to be caused by mutations in the RASA1 gene. The associated phenotype is still subject of debate. The purpose of this study was to conduct a RASA1 mutation analysis in the family that led to the initial discovery of the 5q locus, and to delineate the associated phenotype. A novel truncating mutation was identified in all clinically affected individuals and in none of the unaffected members. The associated phenotype was widely variable; all individuals had multifocal CM with at least one area of high flow. Various additional features were observed, some previously reported and others novel, including limb overgrowth, varicosities, possible lymphatic malformations, localized hyperhidrosis and exercise induced redness. The cause of this wide intramutational phenotypic variability remains to be elucidated.

Chronic pulmonary embolism in Klippel-Trenaunay syndrome.

BACKGROUND: Klippel-Trenaunay syndrome (KTS) is characterized by vascular malformations and disturbed soft tissue or bony growth, involving one or more extremities. A high incidence of venous thromboembolism (VTE) has been reported in this disorder, along with cases of belated diagnosed chronic thromboembolic (CTE) pulmonary hypertension (CTEPH). We performed a cross-sectional study to investigate the prevalence of CTE in patients with KTS. METHODS: Those from our KTS patient cohort willing to participate were examined with a sequential diagnostic workup including perfusion scintigraphy, computed tomography, and echocardiography. RESULTS: Of 68 patients, 48 patients participated in the study (median age 43 years; 29 [60%] were female). Eleven patients (23%) had an abnormal perfusion scan result, of whom computed tomographic scanning showed signs of CTE in two patients (4.2%; 95% confidence interval [CI] 1.2%-14%); both patients had a history of VTE. Echocardiography showed no signs of CTEPH in these patients. In total, 23 patients (48%; 95% CI 35%-62%) had a history of superficial vein thrombosis and 8 patients (17%; 95% CI 8.7%-30%) had a history of deep vein thrombosis or pulmonary embolism, which was associated with more shortness of breath. LIMITATIONS: Echocardiography was only performed in patients with CTE. CONCLUSION: A large proportion of patients with KTS had a history of VTE. The prevalence of CTE in the total KTS cohort, however, appeared less alarming than previously assumed. Based on these results, we suggest that there is only a limited indication for CTEPH screening among patients with KTS. Nevertheless, awareness for CTEPH remains appropriate, especially among patients presenting with shortness of breath and a history of VTE.

A proposal for classification of entities combining vascular malformations and deregulated growth.

BACKGROUND: Agreement on terminology and nomenclature is fundamental and essential for effective exchange of information between clinicians and researchers. An adequate terminology to describe all patients showing vascular malformations combined with deregulated growth is at present not available. OBJECTIVES: To propose a classification of patients with vascular malformations, not restricted to the face, and growth disturbances based on simple, clinically visible characteristics, on which clinicians and researchers can comment and which should eventually lead to an internationally accepted classification. METHODS: Rooted in our joint experience we established a classification of vascular malformation not limited to the face, with growth disturbances. It is based on the nature and localization of the vascular malformations; the nature, localization and timing of growth disturbances; the nature of co-localization of the vascular malformations and growth disturbances; the presence or absence of other features. Subsequently a mixed (experienced and non-experienced) group of observers evaluated 146 patients (106 from the Netherlands; 40 from the UK) with vascular malformations and disturbed growth, using the classification. Inter-observer variability was assessed by estimating the Intra-Class Correlation (ICC) coefficient and its 95% confidence interval. RESULTS: We defined 6 subgroups within the group of entities with vascular malformation-deregulated growth. Scoring the patients using the proposed classification yielded a high inter-observer reproducibility (ICC varying between 0.747 and 0.895 for all levels of flow). CONCLUSIONS: The presently proposed classification was found to be reliable and easy to use for patients with vascular malformations with growth disturbances. We invite both clinicians and researchers to comment on the classification, in order to improve it further. This way we may obtain our final aim of an internationally accepted classification of patients, which should facilitate both clinical treatment and care of, as well as research into the molecular background of entities combining vascular malformation and deregulated growth.

Monozygotic twins discordant for vascular malformations and dysregulated growth.

There is a large group of disorders characterized by non-cranial vascular malformations and a dysregulated growth, of which the prototype may be Klippel-Trenaunay syndrome (KTS). The aetiology of KTS and vascular malformations-dysregulated growth (VM-DG) syndromes resembling KTS is obscure, but polygenic paradominant inheritance involving mutations or polymorphisms in two or more genes simultaneously, of which one (or more) are involved in (lymph)angiogenesis and the other(s) in growth regulation has been proposed for KTS and related VM-DG entities. This provides an explanation for the variability of the VM-DG syndromes through the numerous possible combinations of mutated genes involved. We report on three monozygotic female twins who are discordant for a VM-DG syndrome resembling KTS. We suggest that our observation is consistent with the concept of polygenic paradominant inheritance involving two or more genes. We discuss the published observations in twins discordant for other disorders associated with disturbed growth regulation such as Beckwith-Wiedemann syndrome and Silver-Russell syndrome, and the occurrence in cousins with KTS and Beckwith-Wiedemann syndrome, which are best explained by an imprinting disturbance. We propose that, similarly, disturbed imprinting plays a role in the pathogenesis of VM-DG syndromes in general, and suggest the same may hold for KTS in sensu strictu or Proteus syndrome. Further studies to investigate imprinting status in VM-DG syndromes, including KTS and Proteus syndrome, are warranted.

Baseline Quality of Life in patients with Klippel-Trenaunay syndrome.

BACKGROUND: Klippel-Trenaunay syndrome (KTS) is a congenital group of disorders characterised by vascular malformations (capillary malformation (CM), venous malformation (VM), and lymphatic malformation (LM)) and disturbed growth regulation. The burden caused by KTS symptoms can be evaluated using Quality of Life (QoL)-measuring questionnaires. This study aimed to assess the QoL in KTS patients using the Short Form Health Survey Questionnaire (SF-36) and Skindex-29 questionnaires, and to determine three grades of severity (mild, moderate and severe) according to the scores obtained. In addition, we compared the SF-36 results to those of a general Dutch population sample and a selected group of other chronic conditions. METHODS: KTS patients of the Dutch KTS foundation and of two medical centres answered SF-36 and Skindex-29 questionnaires. Control data of validated Dutch population SF-36 scores and literature-acquired scores for other diseases were available. RESULTS: A total of 78 patients were enrolled, of whom 34 (43.6%) were male; the mean age was 39.3 years (SD: 17.1; range: 12-78 years). The Dutch KTS group scored significantly lower than the general Dutch population on all SF-36 scales except Mental Health and Role Emotional. Furthermore, they scored significantly lower than other medical conditions on the Physical Functioning and Bodily Pain scales. According to the Skindex-29 results, KTS patients fall in the categories - symptoms: severe to very severe; emotions: diminutive to mild and functions: mild. The total score is lower than 40, indicating a negligible negative impact on QoL; however, new cut-off values are being calculated. CONCLUSIONS: Classification according to severity is important to educate patients accordingly, predict prognosis and set treatments. Especially in cases of severe KTS, physicians should not only be attentive to the physical aspects but also to the psychological and social aspects of KTS.

Vascular malformations as underlying cause of chronic thromboembolism and pulmonary hypertension.

We report four patients with chronic thromboembolic pulmonary hypertension (CTEPH) presumably due to recurrent pulmonary embolism from low-flow vascular malformations, and give a review of the literature. Venous malformations, such as those observed in Klippel- Trenaunay syndrome (KTS) can be associated with hypercoagulability, thrombosis and recurrent pulmonary embolism and ultimately CTEPH. Since many physicians appear unfamiliar with these potential complications, patients may experience a delayed diagnosis of this progressive and potentially life-threatening CTEPH.

Klippel-Trenaunay syndrome: diagnostic criteria and hypothesis on etiology.

Klippel-Trenaunay syndrome (KTS) is a congenital malformation syndrome involving blood and lymph vessels and disturbed growth of bone and soft tissues. The clinical presentation can be extremely variable. An extensive literature search showed that various authors used many different diagnostic criteria. Uniform diagnostic criteria are an absolute prerequisite for successful molecular studies and for comparisons between various studies on almost any aspect of the disorder. Based on data from 3 unusually experienced colleagues and our experience, we propose restrictive diagnostic criteria, which still respect the extremely variable nature of KTS. Important aspects are that growth can be both increased and decreased, very small arteriovenous fistula can be present, and varicosities do not need to be present. Several hypotheses regarding cause and pathogenesis in KTS exist, but none explains all KTS characteristics completely. We propose yet another hypothesis which is at variance with the hypothesis of paradominant inheritance.