{"id":"PBD-0095","number":44,"hints":["A 16-year-old boy is referred for colonoscopy with a haemoglobin of 5.9 g/dL and years of fresh blood in his stool.","It was called haemorrhoids when he was six and he has had no regular care since; he is at the clinic this week for cellulitis.","Veins stand engorged around his anus, and CT shows one huge tortuous vein draining the splenic and left iliac veins, wound around the rectum.","The rectum is carpeted with polyps to 10 cm above the anus, dilated vessels crossing their tips. There is no arteriovenous fistula anywhere.","On examination he has light red stains over his trunk and the outer side of both legs, a right arm thicker than the left and an overgrown second toe.","The affected tissue carries a somatic PIK3CA variant at 3q26.32."],"answer":{"name":"Capillary-lymphatic-venous malformation with segmental distribution","aliases":[],"alsoAccepted":["CLVM with segmental distribution","KTS","Klippel-Trénaunay syndrome","angioosteohypertrophy syndrome","haemangiectatic hypertrophy","Klippel-Trenaunay-Weber syndrome","Klippel-Trenaunay-Weber syndrome, Isolated cases","Weber-Klippel-Trenaunay"],"hiddenAliases":[],"mondo":"MONDO:0007864","orpha":"ORPHA:90308","omim":["149000"],"gene":["PIK3CA","AGGF1"],"locus":"3q26.32","inheritance":"Multigenic/multifactorial; Not applicable","prevalence":"<1 / 1 000 000","definition":"A rare congenital complex vascular malformation syndrome characterized by capillary malformations manifesting as wine stains and venous varicosities typically prominent along the lateral aspect of the lower extremities, associated with overgrowth of a limb (most commonly a leg, less frequently other regions of the body), involving bone and/or soft tissues. The diagnosis is usually made in presence of at least two of these three features. Lymphatic malformations are also observed, while arteriovenous fistulas are absent. Patients present recurrent painful thrombophlebitis, venous thrombosis, and sudden venous hemorrhage."},"date":"2026-09-24","today":"2026-09-24","nextRollover":"2026-09-25T03:00:00.000Z"}