Three-month-old boy with multiple birthmarks and hypertrophic left arm.
Infant was born at 38 weeks' gestation to a 33-year-old gravida 2, para 1 after an uncomplicated pregnancy and normal spontaneous vaginal delivery. Birth weight, 3.45 kg; length, 53 cm. Both parents healthy, nonconsanguineous. No family history of growth abnormalities. Father had port-wine stains on nape and chest.
Weight, 6.93 kg; length, 63 cm; head circumference, 39.5 cm. Length of left shoulder to left wrist was 21 cm, whereas that from right shoulder to right wrist was 19.75 cm. Left mid-arm circumference and midforearm circumference, 17.5 cm and 17 cm, respectively. Right mid-arm circumference and mid-forearm circumference, 16 cm and 14.5 cm, respectively. Multiple red birthmarks, especially on the chest, abdomen, left arm, left forearm, and left hand. Remaining examination findings normal.
"WHAT'S YOUR DIAGNOSIS?"