[Maurice Klippel (1858–1942), neurologist and psychiatrist, general medicine chief at Hôpital Tenon in Paris, France]

[Paul Trénaunay (1875–????), neurologist in Paris, France]

= rare sporadic (nonhereditary) combined capillary-venous malformation of trunk + extremities in association with limb overgrowth characterized by a triad of:

1. Port-wine nevus = unilateral large flat infiltrative cutaneous capillary malformation often in dermatomal distribution of affected limb; may fade in 2^nd–3^rd decade
2. Congenital varicose veins / venous malformation affecting superficial + deep venous system = megaveins on lateral aspect of affected limb; usually ipsilateral to capillary malformation
   1. superficial venous system: ectasia of small veins, persistent embryologic veins, large venous malformations
   2. deep venous system:” aneurysmal dilatation, aplasia, hypoplasia, duplications, venous incompetence
3. Gigantism = overgrowth of distal digits / entire extremity (especially during adolescent growth spurt) involving soft-tissue + bone (most variable of the 3 classic features)

VARIANT:Klippel-Trénaunay-Weber syndrome = associated with (4) arteriovenous fistula

Incidence:>1,000 cases reported

Pathogenesis:

failure of regression of large caliber superficial lateral venous channel at 6 weeks GA (= fetal lateral limb bud vein) → varicosity → impaired venous return → tissue overgrowth

Age: usually manifest at birth; M÷F = 1÷1

Associated with:

• polydactyly, syndactyly, clinodactyly, oligodactyly, ectrodactyly, congenital dislocation of hip
• vascular malformation of colon, rectum, bladder (1–10%)
• spinal hemangiomas + AVMs
• hemangiomas in liver / spleen
• lymphangiomas of limb

Location: one lower limb in 75–95% (10–15 x more common than upper extremity); bilateral in <5%; lower limb ± upper limb; extension into trunk may occur

• pain in usually thicker + longer extremity
• spontaneous cutaneous hemorrhage
• chronic venous insufficiency
• cutaneous lymphatic vesicles, lymphorrhea
• elongation of bones:
  • leg-length discrepancy
  • increased metatarsal / metacarpal + phalangeal size
• cortical thickening
• circumferential soft-tissue hypertrophy (at birth / later in life)
• phleboliths in pelvis (bowel wall, anterior wall of urinary bladder) ← prior hemorrhage / thrombus
• pulmonary vein varicosities
• cystic lung lesions

CT / MR:

• slow uptake of contrast material in visceral vascular malformations during delayed phase

Venogram:

• extensive dilation of superficial veins
• enlarged perforating veins
• aplasia / hypoplasia of lower extremity veins (18–40%): ? selective flow of contrast material up the lateral venous channel may fail to opacify the deep venous system
• incompetent valveless collateral venous channels (? persistent lateral limb bud vein = Klippel-Trénaunay vein) arises near the ankle + extends a variable distance up the extremity and drains into deep femoral vein / iliac veins (in >66%)

Color Doppler US:

• deep venous malformations of femoral vein (common)

Lymphangiography:

• hypoplasia of lymphatic system

Cx: stasis dermatitis, thrombophlebitis, cellulitis, deep venous thrombosis, pulmonary embolism, infected lymphangitis ± sepsis, bloody stool, hematuria, epistaxis, Kasabach-Merritt syndrome (= consumptive coagulopathy)

Rx:

1. conservative: application of graded compressive stockings, pneumatic compression devices, percutaneous sclerosis of localized venous malformations / superficial varicosities
2. surgical: epiphysiodesis, excision of soft-tissue hypertrophy, vein stripping, life-threatening bleeding

DDx:

1. Parkes-Weber syndrome congenital persistence of multiple microscopic AV fistulas + spectrum of Klippel-Trénaunay-Weber syndrome (pulsatility, thrill, bruit)
2. Neurofibromatosis (café-au-lait spots, axillary freckling, cutaneous neurofibromas, macrodactyly ← plexiform neurofibromas, wavy cortical reaction, early fusion of growth plate, limb hypertrophy not as extensive / bilateral)
3. Beckwith-Wiedemann syndrome (aniridia, macroglossia, cryptorchidism, Wilms tumor, broad metaphyses, thickened long-bone cortex, advanced bone age, periosteal new-bone formation, hemihypertrophy)
4. Macrodystrophia lipomatosis (hyperlucency of fat, distal phalanges most commonly affected, overgrowth ceases with puberty, usually limited to digits)
5. Maffucci syndrome (cavernous hemangiomas, soft tissue hypertrophy, phleboliths, multiple enchondromas)
6. Cutis marmorata telangiectatica congenita
7. Servelle-Martorell syndrome