In-Service Exam
Lymphedema - 2003





PHOTO

The photograph shown above is of an otherwise healthy 7-year-old boy who has had progressive enlargement of the right upper extremity with pitting edema since birth. Radiographs of the right upper extremity show bone growth that is normal and equal to the left upper extremity. An enhanced MRI shows normal soft tissues.

This patient's findings are most consistent with

(A) Klippel-TrŽnaunay syndrome
(B) lymphatic malformation
(C) lymphedema praecox
(D) Milroy's disease
(E) proteus syndrome

The correct response is Option D.

The findings in this 7-year-old boy are most consistent with Milroy's disease, a rare, X-linked, autosomal dominant form of primary lymphedema that is diagnosed at birth. Unilateral pitting edema is seen in this patient and is in fact associated with all forms of lymphedema. Ocular manifestations have occurred in some patients. Radiographs will show normal bone growth and no hemihypertrophy of the affected extremity. MRI of the soft tissues may also be unremarkable.

Klippel-TrŽnaunay syndrome is characterized by limb hemihypertrophy, most frequently affecting the leg, and lymphovenous malformations, often with a cutaneous component. A T1-weighted MRI will show a slow-flow lesion. Lymphedema is seen in as many as 30% of these patients. In infrequent cases, limb hypoplasia has been present in place of hypertrophy. A gadolinium-enhanced MRI is needed to distinguish lymphovenous malformations from mere lymphatic or venous lesions.

Lymphatic malformations are composed of lymph-filled dysplastic vessels that can be classified as macrocystic, microcystic, or combined. Ultrasonography can be used to diagnose lymphatic malformations in utero or after birth. MRI will also aid in delineating a lymphatic malformation from lymphedema.

Lymphedema praecox is a noncongenital form of lymphedema; signs and symptoms usually first occur before puberty. Another form, lymphedema tarda, occurs in midlife.

Proteus syndrome is a sporadic condition characterized by vascular, skeletal, and soft-tissue abnormalities. Common findings include growth asymmetry and subcutaneous tumor-like structures, such as lipomas, Schwann cell structures, and lipomatosis. Associated vascular anomalies may include capillary malformations, lymphatic malformations, capillary venous malformations, and combined lymphovenous malformations, all of which will appear abnormal on MRI.

References
1. Pederson WC. Lymphedema of the extremities. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:1124-1130.
2. Puckett CL. Lymphedema of the upper extremity. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;7:5023-5031.