Cancer Risk in Klippel-Trenaunay Syndrome

Genetic Predisposition to Sarcoma: What Should Clinicians Know?

OPINION STATEMENT

Pathogenic germline variants in the setting of several associated cancer predisposition syndromes (CPS) may lead to the development of sarcoma. We would consider testing for a CPS in patients with a strong family history of cancer, multiple primary malignancies, and/or pediatric/adolescent/young adult patients diagnosed with other malignancies strongly associated with CPS. When a CPS is diagnosed in a patient with sarcoma, additional treatment considerations and imaging options for those patients are required. This applies particularly to the use of radiation therapy, ionizing radiation with diagnostic imaging, and the use of alkylating chemotherapy. As data and guidelines are currently lacking for many of these scenarios, we have adopted a shared decision-making process with patients and their families. If the best chance for cure in a patient with CPS requires utilization of radiation therapy or alkylating chemotherapy, we discuss the risks with the patient but do not omit these modalities. However, if there are treatment options that yield equivalent survival rates, yet avoid these modalities, we elect for those options. Considering staging imaging and post-therapy evaluation for sarcoma recurrence, we avoid surveillance techniques that utilize ionizing radiation when possible but do not completely omit them when their use is indicated.

Low risk of embryonic and other cancers in PIK3CA-related overgrowth spectrum: Impact on screening recommendations

The PIK3CA-related overgrowth spectrum (PROS) encompasses various conditions caused by mosaic activating PIK3CA variants. PIK3CA somatic variants are also involved in various cancer types. Some generalized overgrowth syndromes are associated with an increased risk of Wilms tumor (WT). In PROS, abdominal ultrasound surveillance has been advocated to detect WT. We aimed to determine the risk of embryonic and other types of tumors in patients with PROS in order to evaluate surveillance relevance. We searched the clinical charts from 267 PROS patients for the diagnosis of cancer, and reviewed the medical literature for the risk of cancer. In our cohort, six patients developed a cancer (2.2%), and Kaplan Meier analyses estimated cumulative probabilities of cancer occurrence at 45 years of age was 5.6% (95% CI = 1.35%-21.8%). The presence of the PIK3CA variant was only confirmed in two out of four tumor samples. In the literature and our cohort, six cases of Wilms tumor/nephrogenic rests (0.12%) and four cases of other cancers have been reported out of 483 proven PIK3CA patients, in particular the p.(His1047Leu/Arg) variant. The risk of WT in PROS being lower than 5%, this is insufficient evidence to recommend routine abdominal imaging. Long-term follow-up studies are needed to evaluate the risk of other cancer types, as well as the relationship with the extent of tissue mosaicism and the presence or not of the variant in the tumor samples.

Klippel-Trenaunay Syndrome, Segmental/Focal Overgrowth Malformations: A Review

Klippel-Trenaunay syndrome is an uncommon, infrequent, congenital disorder characterized by a triad of capillary malformation, varicosities, and tissue and bone hypertrophy. The presence of two of these three signs is enough to obtain the diagnosis. Capillary malformations are usually present at birth, whereas venous varicosities and limb hypertrophy become more evident later. The syndrome has usually a benign course, but serious complications involving various organs, such as gastrointestinal and genitourinary organs, as well as the central nervous system, may be observed. Recently, Klippel-Trenaunay syndrome has been included in the group of PIK3CA-related overgrowth spectrum (PROS) disorders. In terms of this disorder, new results in etiopathogenesis and in modalities of treatment have been advanced. We report here a review of the recent genetic findings, the main clinical characteristics and related severe complications, differential diagnoses with a similar disorder, and the management of patients with this complex and uncommon syndrome.

Current concepts of vascular anomalies

Vascular anomalies encompass a variety of malformations and tumors that can result in severe morbidity and mortality in both adults and children. Advances have been made in the classification and diagnosis of these anomalies, with the International Society for the Study of Vascular Anomalies establishing a widely recognized classification system. In recent years, notable progress has been made in genetic testing and imaging techniques, enhancing our ability to diagnose these conditions. The increasing sophistication of genetic testing has facilitated the identification of specific genetic mutations that help treatment decisions. Furthermore, imaging techniques such as magnetic resonance imaging and computed tomography have greatly improved our capacity to visualize and detect vascular abnormalities, enabling more accurate diagnoses. When considering reconstructive surgery for facial vascular anomalies, it is important to consider both functional and cosmetic results of the procedure. Therefore, a comprehensive multidisciplinary approach involving specialists from dermatology, radiology, and genetics is often required to ensure effective management of these conditions. Overall, the treatment approach for facial vascular anomalies depends on the type, size, location, and severity of the anomaly. A thorough evaluation by a team of specialists can determine the most appropriate and effective treatment plan.

[Rare tumors: Angiosarcoma]

Angiosarcomas are a rare subtype representing 1-2% of soft tissue sarcomas. Risk factors are rarely elucidated but radiotherapy and lymphedema are the most common ones, usually following local treatment for local breast cancer. Despite the improvement of our knowledge, the prognosis remains poor with 35-40% of 5 year-overall survival. Local treatment when feasible should include a R0 surgery completed with adjuvant radiation. When metastatic, front lines chemotherapies include doxorubicine or weekly paclitaxel. If possible, in oligometastatic patients, metastasectomy should always be considered allowing the best responses. The knowledge of angiosarcoma's biology is rapidly increasing and new biomarkers are emerging. The use of immunotherapy in particular subtypes including head and neck angiosarcomas shows promising results. The model of the angiosarcoma project, a patient-participating study, seems to be an excellent way to study rare tumors. We should focus our efforts on understanding the underlying molecular biology to propose the best precision medicine for those patients.

French national diagnosis and care protocol (PNDS, protocole national de diagnostic et de soins): cystic lymphatic malformations

Cystic lymphatic malformations (LMs) are rare chronic conditions which management differs according to the type (macrocystic LMs, microcystic LMs or both). Studies are lacking due to rarity of the pathology. We aimed to establish a French National Diagnosis and Care Protocol (PNDS: Protocole National de Diagnostic et de Soins), to provide health professionals with free open access synthesis on optimal management and care of patients with LMs ( https://www.has-sante.fr/upload/docs/application/pdf/2021-03/malformations_lymphatiques_kystiques_-_pnds.pdf ). The process included a critical review of the literature and multidisciplinary expert consensus. LMs are congenital but are not always discovered at birth. Nearly 75% of them are located in the head and neck because of the highly dense lymphatic system in this region. Physical examination (showing painless masses with normal skin color and depressible consistency, or cutaneous/mucosal lymphangiectasia) and color Doppler ultrasonography, usually allow for diagnosis. MRI (involving T2 sequences with fat saturation in at least two spatial planes) is the tool of choice for evaluating anatomical extension, characterizing lesions (microcystic and macrocystic), and before considering therapeutic management. A biopsy, coupled to a blood sample, can also be used for molecular biology analyses, to search for activating mutations of the PIK3CA gene, particularly with LM integrating in a syndromic form (CLOVES or Klippel-Trenaunay syndrome) but also in certain isolated (or common) LMs. The spontaneous evolution of LMs, in particular microcystic forms, is often toward progressive aggravation, with an increase in the number of vesicles, thickening, increased oozing and bleeding, while pure macrocystic LMs may regress due to "natural sclerosis", i.e. fibrosis secondary to an inflammatory reorganization after common infantile infections. In case of voluminous LMs or syndromic forms, functional and psychological repercussions can be major, deteriorating the patient's quality of life. LMs must be treated by physicians integrated in multidisciplinary teams, and be personalized. Management is a life-long process that involves one or several of these therapies: conservative management, physical therapy (compression), sclerotherapy, surgery, drugs such as mTOR inhibitors (sirolimus), that has shown efficacy in decreasing the volume of LMs, and, more recently, PI3K-inhibitors in syndromic forms. Psychological and social support is necessary, taking into account the patient and his family.

How we approach complex vascular anomalies and overgrowth syndromes

Vascular anomalies, both vascular tumors and vascular malformations, can occur in isolation or as part of syndromes including those which feature phenotypic overgrowth. To update what is known about vascular anomalies associated with overgrowth, PubMed was searched for "overgrowth syndromes and vascular anomalies or malformations." PubMed, OMIM, and the Rare Disease Database also were searched for specific diagnoses. We review individual overgrowth syndromes, provide a case-based approach to the clinical, radiographic, pathologic, and genetic basis for diagnosis, to complications of both the vascular anomalies and the overgrowth, and emphasize the need for a multidisciplinary approach to care.

Case Report: Primary Pleural Angiosarcoma in a Patient With Klippel-Trenaunay Syndrome

Klippel-Trenaunay syndrome (KTS) was demonstrated as a mosaic activating PIK3CA mutations related overgrowth syndrome. We present the first case of primary pleural angiosarcoma in a 17-year-old woman with a history of KTS. The combined targeted DNA and RNA sequencing revealed an activating mutation in PIK3CA in the tumor tissue. Our case suggested an association and perhaps a causal link between the two different PIK3CA-related genetic diseases.

Non-hotspot PIK3CA mutations are more frequent in CLOVES than in common or combined lymphatic malformations

Background

Theragnostic management, treatment according to precise pathological molecular targets, requests to unravel patients’ genotypes. We used targeted next-generation sequencing (NGS) or digital droplet polymerase chain reaction (ddPCR) to screen for somatic PIK3CA mutations on DNA extracted from resected lesional tissue or lymphatic endothelial cells (LECs) isolated from lesions. Our cohort (n = 143) was composed of unrelated patients suffering from a common lymphatic malformation (LM), a combined lymphatic malformation [lymphatico-venous malformation (LVM), capillaro-lymphatic malformation (CLM), capillaro-lymphatico-venous malformation (CLVM)], or a syndrome [CLVM with hypertrophy (Klippel-Trenaunay-Weber syndrome, KTS), congenital lipomatous overgrowth-vascular malformations-epidermal nevi -syndrome (CLOVES), unclassified PIK3CA-related overgrowth syndrome (PROS) or unclassified vascular (lymphatic) anomaly syndrome (UVA)].

Results

We identified a somatic PIK3CA mutation in resected lesions of 108 out of 143 patients (75.5%). The frequency of the variant allele ranged from 0.54 to 25.33% in tissues, and up to 47% in isolated endothelial cells. We detected a statistically significant difference in the distribution of mutations between patients with common and combined LM compared to the syndromes, but not with KTS. Moreover, the variant allele frequency was higher in the syndromes.

Conclusions

Most patients with an common or combined lymphatic malformation with or without overgrowth harbour a somatic PIK3CA mutation. However, in about a quarter of patients, no such mutation was detected, suggesting the existence of (an)other cause(s). We detected a hotspot mutation more frequently in common and combined LMs compared to syndromic cases (CLOVES and PROS). Diagnostic genotyping should thus not be limited to PIK3CA hotspot mutations. Moreover, the higher mutant allele frequency in syndromes suggests a wider distribution in patients’ tissues, facilitating detection. Clinical trials have demonstrated efficacy of Sirolimus and Alpelisib in treating patients with an LM or PROS. Genotyping might lead to an increase in efficacy, as treatments could be more targeted, and responses could vary depending on presence and type of PIK3CA-mutation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01898-y.

Oversupply of Limiting Cell Resources and the Evolution of Cancer Cells: A Review

Cancer prevention is superior to cancer treatment—indeed, understanding and controlling cancer risk is a key question in the fields of applied ecology and evolutionary oncology. Ecological cancer risk models offer the dual benefit of being generalizable across cancer types, and unveiling common mechanisms underlying cancer development and spread. Understanding the biological mechanisms of cancer risk may also guide the design of interventions to prevent cancer. Ecological considerations are central to many of these mechanisms; as one example, the ecologically-based hypothesis of metabolic cancer suppression posits that restricted vascular supply of limiting resources to somatic tissues normally suppresses the evolution of somatic cells toward cancer. Here we present a critical review of published evidence relevant to this hypothesis, and we conclude that there is substantial evidence that cancer risk does increase with an abnormal excess of limiting cell resources, including both dietary macronutrients as well as certain micronutrients.

Skin-Related complications of Klippel-Trenaunay Syndrome: a retrospective review of 410 patients

BACKGROUND

Little is known about skin-related complications in Klippel-Trenaunay syndrome (KTS), a complex vascular anomaly defined by capillary malformation (CM), venous malformation (VM) ± lymphatic malformation (LM) and limb overgrowth. Reported skin-related complications of KTS include ulceration, vascular ectasias (blebs), bleeding and infection.

OBJECTIVE

To determine the spectrum, prevalence and predictors of skin-related complications in KTS.

METHODS

A retrospective review of 410 patients fulfilling KTS criteria was performed to assess for the presence of skin-related complications.

RESULTS

Skin-related complications were present in 45% of patients. Most prevalent were CM-related complications including blebs, bleeding, thickening (25%), cellulitis (22%) and ulceration (21%). Features positively associated with skin-related complications were presence of LM (OR 17.17; P < 0.001), VM on the buttocks/perineum/genitalia (OR 1.92; P = 0.009), CM on the feet (OR 1.77; P = 0.039) and male sex (OR 1.63; P = 0.034). Features negatively associated with skin-related complications were CM on the trunk (OR 0.59; P = 0.029) and tissue hypertrophy of the hands (OR 0.27; P = 0.025).

CONCLUSION

Skin-related complications affect nearly half of patients with KTS. Those with lymphatic involvement or malformation presence in the undergarment area or feet are most at risk.

Periosteal new bone formation in Klippel-Trénaunay syndrome: a case report

BACKGROUND

Klippel-Trénaunay syndrome (KTS) is a complex congenital vascular disorder, typically accompanied by port-wine stains, varicose veins, and limb hypertrophy. This paper reports a rare and unusual clinical condition of periosteal reaction in a pediatric case of KTS. Although periosteal new bone formation is not rare in children, as is KTS, their dual occurrence or the presentation of the former due to KTS has not been previously documented. Our objective in this study is to highlight the potential association between periosteal new bone formation and KTS, as well as to help physicians consider this association when bone neoplasm has been ruled out.

CASE PRESENTATION

A 7-year old girl, initially presented with a persistent mild swelling in her left shank, with no abnormalities in the X-ray of the tibiofibular. However, after a few consults and examinations, 7 weeks later, a 17 cm-long periosteal new bone formation along the left tibia and diffused dilated vessels in the left shank were revealed by the radiological examination. Not knowing the true nature of the fast-growing lesion in a typical case of KTS was worrying. Therefore, a core needle biopsy was performed. The test demonstrated a possible parosteal hemangioma. Following further investigation through an excisional biopsy, and a pathological analysis, hyperplasia of the bone tissues with no tumor cells was revealed. Thereafter, an elastic stocking treatment was prescribed. During the first two-year follow-up, recurrence of the mass or sign of progression of KTS was not observed.

CONCLUSIONS

Periosteal new bone formation is a potential manifestation of KTS. Based on the conclusive pathological results of the excisional biopsy, invasive examinations and surgeries could be avoided in future KTS-subperiosteal lesion manifestations.

PIK3CA vascular overgrowth syndromes: an update

PURPOSE OF REVIEW

Over the past decade many previously poorly understood vascular malformation disorders have been linked to somatic activating mutations in PIK3CA, which regulates cell survival and growth via activation of the mTOR1-AKT pathway. The goal of this article is to describe and provide an update on the clinical features, complications, and management strategies for the PIK3CA-related overgrowth spectrum (PROS).

RECENT FINDINGS

PROS encompasses a heterogenous group of disorders with complications related to the tissues harboring the mutation. Vascular malformation syndromes, such as Klippel-Trenaunay syndrome and Congenital Lipomatous Overgrowth Vascular malformations Epidermal nevi and Skeletal abnormalities, have an increased risk of thromboembolic complications, which is accentuated postprocedurally. Asymmetric overgrowth, particularly of limbs, results in a high rate of orthopedic complications. Hypoglycemia screening in the neonatal period and ongoing monitoring for growth failure is recommended in megalencephaly capillary malformation due to its association with multiple endocrinopathies. Recently, sirolimus, an mTOR1 inhibitor, has shown promise in vascular anomalies and now PROS. PIK3CA direct inhibitor, Alpelisib (BYL719), was recently trialed with significant clinical benefit.

SUMMARY

As the pathogenesis of these conditions is better elucidated and targeted treatments are developed, recognizing the clinical features, comorbidities, and evolving therapeutic landscape across the PROS spectrum becomes more crucial for optimization of care.

Childhood Vascular Tumors

Vascular tumors in pediatric patients are an important entity for the clinician to recognize and correctly diagnose. They may present at birth or develop at any point during infancy, childhood, or adolescence. Most are benign, but even benign lesions may have significant morbidity without proper intervention. Malignant vascular tumors are also rarely seen in the pediatric population, and may be associated with various syndromes.