Understanding Pediatric Klippel-Trenaunay Syndrome and Its Rarer Manifestations

Pediatric Klippel-Trenaunay syndrome represents a complex congenital vascular overgrowth disorder that classically presents with capillary malformations, venous abnormalities, and soft-tissue or bony hypertrophy. However, deep intramuscular vascular lesions rarely appear in children. Consequently, these atypical presentations can confound treating physicians. In most clinical scenarios, patients demonstrate the classic superficial triad early in life. Nevertheless, extensive skeletal muscle invasion can simulate aggressive neoplasms or skeletal dysplasias. A recent pediatric case involving a twelve-year-old boy highlights this clinical challenge. The patient experienced chronic right lower extremity swelling from birth alongside recurrent bouts of bacterial cellulitis. Additionally, he developed chronic cutaneous ulcers, persistent purulent wound drainage, and progressive lower-limb asymmetry. Prior to definitive multidisciplinary assessment, the patient underwent four separate soft-tissue excisions without lasting relief. Laboratory evaluation demonstrated severe microcytic hypochromic anemia and markedly elevated inflammatory markers due to chronic secondary infection. Therefore, clinicians must recognize that atypical tissue overgrowth may penetrate deep fascial compartments. While classic cutaneous manifestations usually guide the diagnosis, atypical intramuscular anomalies demand thorough systematic investigation to avoid dangerous diagnostic delays and inappropriate surgical interventions.

Clinical Features and Diagnostic Pitfalls of Deep Intramuscular Involvement

Deep soft-tissue vascular anomalies present substantial diagnostic dilemmas for pediatricians and surgeons alike. Specifically, intramuscular cavernous malformations create firm, palpable masses that clinicians frequently misinterpret as primary musculoskeletal tumors. Moreover, repetitive thrombotic episodes within low-flow vascular channels trigger localized inflammatory responses and tissue fibrosis. In this reported pediatric case, physical examination revealed bilateral nodular ulcerated lesions, marked soft-tissue hypertrophy, and localized macrodactyly. Furthermore, the presence of palpable subcutaneous calcifications complicated the clinical picture. These calcified vascular concretions or phleboliths often resemble osseous lesions on superficial physical examination. In addition, persistent venous hypertension and secondary lymphatic disruption generate cutaneous skin changes that mimic chronic infectious dermatoses. Because the patient suffered recurrent episodes of cellulitis, chronic purulent discharge masked the underlying vascular etiology. Consequently, repeated surgical excisions took place before clinicians investigated the deeper vascular architecture. Hence, pediatric specialists must maintain a high index of suspicion whenever soft-tissue swelling fails to resolve with standard wound care. Recognizing these critical physical features early prevents progressive functional morbidity, systemic infection, and unnecessary operative procedures.

Distinguishing Pediatric Klippel-Trenaunay Syndrome from Maffucci Syndrome

The presence of calcified vascular lesions alongside progressive limb hypertrophy immediately raises suspicion for other rare congenital syndromes. In particular, clinicians often consider Maffucci syndrome because it features multiple cavernous hemangiomas or venous malformations accompanied by hard calcified nodules. However, Maffucci syndrome fundamentally requires the coexistence of multiple enchondromas, which are benign cartilaginous tumors situated within bone metaphyses. Therefore, differentiating pediatric Klippel-Trenaunay syndrome from Maffucci syndrome hinges on detailed skeletal radiological evaluation and histopathology. In the reported child, comprehensive radiographic and magnetic resonance imaging demonstrated no signs of enchondromas or bone marrow pathology. Furthermore, definitive histopathological analysis of the resected tissue revealed classic benign cavernous vascular channels lined by endothelial cells without malignant proliferation. In contrast, Maffucci syndrome carries a high risk of secondary malignant transformation into chondrosarcomas. Thus, establishing an accurate distinction significantly alters long-term oncologic surveillance and therapeutic planning. Clinicians can confidently rule out dysplastic cartilaginous disorders by integrating imaging modalities with microscopic tissue verification, ensuring appropriate conservative and surgical management.

Imaging Protocols: Doppler Ultrasonography and Contrast-Enhanced MRI

Accurate characterization of complex vascular anomalies relies on systematic and sequential imaging modalities. Initially, Doppler ultrasonography serves as an invaluable, non-invasive first-line tool for evaluating hemodynamic flow patterns. In this pediatric case, duplex sonography confirmed patent deep veins alongside extensive superficial venous dilatation, incompetent perforating vessels, and marked venous reflux. Furthermore, ultrasound readily detected calcified cavernous lesions and soft-tissue hypertrophy without evidence of high-flow arteriovenous shunts. Subsequently, contrast-enhanced magnetic resonance imaging provided indispensable anatomical resolution of deeper structures. The scans revealed extensive intramuscular malformations infiltrating the gastrocnemius and tibialis muscles. Notably, the adjacent bone marrow and articulation spaces remained completely unaffected. Magnetic resonance imaging clearly delineated the precise margins of soft-tissue involvement, which is essential for planning surgical debulking. In addition, this advanced modality effectively excluded visceral vascular involvement and deep venous thrombosis. Therefore, combining Doppler sonography with high-resolution magnetic resonance imaging establishes an accurate diagnostic blueprint. This multimodality imaging strategy guides subsequent surgical interventions, particularly in resource-limited clinical environments where specialized molecular diagnostics remain unavailable.

Management Strategies: Surgical Debulking and Conservative Care

Managing advanced pediatric vascular malformations requires a balanced approach combining targeted surgical intervention and meticulous conservative care. When extensive intramuscular lesions cause progressive physical deformity, intractable ulceration, or chronic infection, surgical debulking becomes necessary. In this challenging case, surgeons carefully excised the symptomatic intramuscular masses while establishing adequate wound drainage. Concurrently, medical teams administered culture-directed intravenous antibiotics to eradicate chronic bacterial colonization and resolve secondary cellulitis. Following successful debulking and infection control, the surgical team achieved primary healing with uneventful postoperative recovery. Nevertheless, complete surgical extirpation of extensive low-flow intramuscular malformations remains impractical due to high risks of neurovascular damage and excessive hemorrhage. Consequently, long-term conservative surveillance forms the cornerstone of post-surgical rehabilitation. Clinicians recommend graduated compression garments to counteract venous pooling, reduce dependent edema, and alleviate chronic pain. Additionally, routine surveillance monitors for late complications such as deep venous thrombosis, thrombophlebitis, or recurrent ulceration. Ultimately, this coordinated multidisciplinary strategy optimizes limb function, controls chronic symptoms, and ensures durable quality of life for growing pediatric patients.

Frequently Asked Questions

How do clinicians differentiate KTS from Maffucci syndrome in children?

Clinicians differentiate Klippel-Trenaunay syndrome from Maffucci syndrome through combined radiographic, clinical, and histopathologic evaluations. Maffucci syndrome specifically features multiple enchondromas alongside vascular malformations, whereas Klippel-Trenaunay syndrome causes limb hypertrophy, superficial varicose veins, and capillary stains without true cartilaginous tumors. Therefore, magnetic resonance imaging and plain radiographs confirm the absence of skeletal enchondromas, while histological evaluation demonstrates benign cavernous vascular channels without neoplastic cartilage proliferation.

Why is magnetic resonance imaging crucial for intramuscular vascular malformations?

Contrast-enhanced magnetic resonance imaging provides exceptional soft-tissue resolution necessary for assessing complex intramuscular vascular lesions. It precisely maps the anatomical boundaries within affected muscle groups, such as the gastrocnemius and tibialis muscles, while ruling out marrow invasion. Furthermore, magnetic resonance venography evaluates patency in the deep venous system and identifies aberrant drainage pathways. This comprehensive anatomical detail guides surgical debulking safely and prevents catastrophic neurovascular injury during operative interventions.

What are the primary treatment goals for pediatric patients with symptomatic KTS?

Primary treatment goals focus on alleviating symptoms, preserving functional limb mobility, and preventing life-threatening secondary complications. Clinicians prioritize controlling recurrent cellulitis through targeted antibiotic therapy, optimizing wound care, and debulking severely symptomatic intramuscular masses. Subsequently, long-term conservative management utilizes graduated elastic compression therapy, physical rehabilitation, and regular duplex monitoring. This multidisciplinary protocol minimizes dependent venous hypertension, reduces localized edema, and lowers the lifetime risk of thromboembolic events.

Disclaimer: This content is for informational and educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Medical knowledge is constantly evolving. Refer to the latest local and national guidelines for clinical practice.

References

Shah SS et al. Deep Intramuscular Vascular Malformations in Pediatric Klippel-Trenaunay Syndrome Mimicking Maffucci Syndrome: A Case Report. Clin Case Rep. 2026 Nov undefined. doi: 10.1002/ccr3.73825. PMID: 42964341.
StatPearls. Klippel-Trenaunay-Weber Syndrome. Treasure Island (FL): StatPearls Publishing; 2023.
Alomari AI, et al. Clinical Practice Guidelines for Klippel-Trenaunay Syndrome. Boston Children's Hospital Vascular Anomalies Center; 2016.