(A) Klippel-Trénaunay syndrome
(B) Parkes-Weber syndrome
(C) Rendu-Osler-Weber syndrome
(D) Sturge-Weber syndrome
(E) von Hippel-Lindau disease

The correct response is Option E.

Patients with von Hippel-Lindau disease have hemangiomas affecting the retina and hemangioblastomas of the cerebellum and visceral organs. Seizures and mental retardation may also be associated.

Klippel-Trénaunay syndrome is characterized by a port-wine stain (typically involving one extremity) overlying venous and lymphatic malformations.

Parkes-Weber syndrome is similar to Klippel-Trénaunay syndrome but is differentiated by the presence of arteriovenous fistulas.

Rendu-Osler-Weber syndrome, or hereditary hemorrhagic telangiectasia, is an autosomal dominant disorder characterized by multiple ectatic vessels involving the skin, mucous membranes, and visceral organs. Epistaxis, hematuria, hematemesis, and melena are frequently associated.

Sturge-Weber syndrome is associated with a large vascular malformation, usually a port-wine stain, in the distribution of the first and second branches of the trigeminal nerve (V1 and V2). Other findings include focal motor seizures, hemiparesis, and visual field defects, especially glaucoma. Mental retardation may result from leptomeningeal venous malformations.

References
1. Boyd JB, Mulliken JB, Kaban LB, et al. Skeletal changes associated with vascular malformations. Plast Reconstr Surg. 1984;74:789.
2. Burns AJ, Mulliken JB. Cutaneous vascular anomalies, hemangiomas, and malformations. In: Georgiade GS, Riefkohl R, Levin LS, eds. Textbook of Plastic, Maxillofacial and Reconstructive Surgery. 3rd ed. Baltimore, Md: Williams & Wilkins; 1997:178-197.
3. Mulliken JB. Cutaneous vascular anomalies. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;5:3191-3274.
4. Young AE. Venous and arterial malformations. In: Mulliken JB, Young AE, eds. Vascular Birthmarks: Hemangiomas and Malformations. Philadelphia, Pa: WB Saunders Co; 1988:196-214.

A 26-year-old man has had progressive enlargement of the left arm over the past 10 years. A photograph is shown above. Neurapraxia of the median and ulnar nerves developed recently. The right arm decompresses when he lifts his hand over his head.

Which of the following is the most likely diagnosis?

(A) Arteriovenous malformation
(B) Capillary malformation
(C) Hemangioma
(D) Lymphatic malformation
(E) Venous malformation

The correct response is Option E.

This patient most likely has a venous malformation, which is characterized by compressibility and a propensity to fill with blood when the patient changes body positions. It is usually larger and extends deeper than its superficial structure indicates, and it frequently intertwines with neurovascular components, which may affect the function of the involved extremity. When a venous malformation is associated with thrombosis, pain may result.

Arteriovenous malformations are high-flow lesions characterized by rapid blood flow through multiple feeding vessels. Pulsations and temperature changes in the affected area are associated, but dermal involvement is minimal. A bruit or thrill is heard on auscultation.

Capillary malformations, or port-wine stains, have abnormalities limited to the capillaries in the dermis. These lesions are present at birth and do not regress spontaneously. If left untreated, cobblestoning, ectasia, and progressive
darkening may occur. Patients with facial port-wine stains involving the first (ophthalmic) or second (maxillary) divisions of the trigeminal nerve (V1 and V2) are at significantly greater risk for ocular or nervous system involvement.
Hemangiomas typically appear shortly after birth and proliferate for several months before spontaneously regressing. They are characterized by proliferative primitive endothelial cell nests in syncytial masses, with and without vessel lumens.

Lymphatic malformations can be superficial or deep. Superficial lymphatic malformations are comprised of anomalous lymphatic remnants that manifest as clear vesicles. Deep lymphatic malformations appear similar to hemangiomas but are soft and compressible on palpation. Bony overgrowth is associated.

References
1. Mulliken JB. Cutaneous vascular anomalies. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;5:3191-3274.
2. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plast Reconstr Surg. 1982;69:412-422.

Which of the following vascular lesions is characterized by an arteriole central vessel?

(A) Macular stain
(B) Port-wine stain
(C) Pyogenic granuloma
(D) Spider angioma
(E) Strawberry hemangioma

The correct response is Option D.

Spider angioma, or arteriolar malformation, is a small vascular malformation that contains a central blanching arteriole vessel. Spider angiomas occur on the face in both children and adults. Obliteration of the central feeding arteriole is the goal of treatment; otherwise, the lesion will continue to enlarge. Laser therapy or electrocautery is recommended.

Macular stains are typically seen on the skin of neonates and are not true vascular nevi.

Port-wine stains are capillary vascular malformations of the face that are seen at birth and grow commensurately with the child.

Pyogenic granulomas are reparative vascular lesions commonly seen on the head and neck in children. Because these lesions receive their blood supply primarily from capillaries, they are not true vascular malformations.

A strawberry hemangioma is a venous malformation that is typically seen at birth and enlarges during the first few months of life. These lesions do not grow commensurately with the child.

References
1. Achauer BM, Vander Kam VM. Vascular lesions. Clin Plast Surg. 1993;20:43-51.
2. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plast Reconstr Surg. 1982;69:412-420.

Histopathologic examination of a proliferating hemangioma is most likely to show each of the following characteristics EXCEPT

(A) decreased 17-beta estradiol binding sites
(B) increased collagenase activity
(C) increased quantity of mast cells
(D) multilaminate basement membrane
(E) plump endothelial cells

The correct response is Option A.

Hemangiomas are true benign neoplasms that have plump, rapidly dividing endothelial cells and an increased quantity of mast cells on histopathologic examination. These mast cells produce heparin, which is believed to be the primarily stimulus for migration of capillary endothelial cells. The number of mast cells begins to decrease as the hemangioma involutes.

During the proliferation phase of a hemangioma, the levels of circulating 17-beta estradiol are increased. In addition, the number of binding sites for 17-beta estradiol is actually increased, not decreased. Collagenase activity is increased in all enlarging hemangiomas as the endothelial cells destroy the basement membrane to allow for the formation of new capillary tubules. A multilaminate basement membrane is also observed.

In contrast, vascular malformations exhibit flattening of the endothelium, thinning of the basement membrane, and a normal quantity of mast cells.
References
1. Ausprunk DH, Folkman J. Migration and proliferation of endothelial cells in preformed and newly formed blood vessels during tumor angiogenesis. Microvasc Res. 1977;14:53.
2. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants & children: a classification based on endothelial characteristics. Plast Reconstr Surg. 1982;69:412.
3. Sasaki GH, Pang CY, Wittliff JL. Pathogenesis and treatment of infant skin strawberry hemangiomas: clinical and in vitro studies of hormonal effects. Plast Reconstr Surg. 1984;73:359.
4. Stal GH, Hamilton S, Spira M. Hemangiomas, lymphangiomas, and vascular malformations of the head and neck. Otolaryngol Clin North Am. 1986;19:769.

A 38-year-old man has a pulsatile mass on the volar aspect of the distoradial forearm three weeks after sustaining a stab wound to the forearm. At the time of injury, he controlled the bleeding successfully by applying pressure to the wound and did not seek treatment. Which of the following is the most likely diagnosis?

(A) Aneurysm
(B) Arteriovenous fistula
(C) Pseudoaneurysm
(D) Ulnar artery thrombosis
(E) Vascular malformation

The correct response is Option C.

The most likely diagnosis is pseudoaneurysm, which has occurred secondary to trauma in the area of the radial artery. This patient sustained a stab wound to the forearm that immediately began to bleed. Although he controlled the bleeding at the time of injury, a pulsatile mass developed subsequently. Because obtaining a biopsy specimen can result in significant hemorrhage in these patients, it is important to carefully review preceding history, which is consistent with pseudoaneurysm in this situation.

This patient’s history is not consistent with a true aneurysm, and examination findings rule out an arteriovenous fistula.

Ulnar artery thrombosis is also known as hypothenar hammer syndrome because it occurs secondary to localized trauma in construction workers or other persons who strike objects with their hands. Typical symptoms include pain, paresthesia, decreased temperature, color changes, pallor, and numbness of the ulnarmost digits.

Vascular malformations are usually present at birth, but may develop and enlarge over time. A thrill or bruit is frequently associated, and color changes may occur.

References
1. Angelides AC. Ganglions of the hand and wrist. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:2171-2183.
2. Koman LA, Ruch DS, Smith BP, et al. Vascular disorders. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:2254-2302.

A 4-year-old boy has a 4 ( 8-cm compressible mass of the soft tissue of the volar forearm that has enlarged over the past year. He also has worsening pain in the forearm. Physical examination shows intact skin over the forearm; a thrill can be palpated over the mass. The mass does not decompress fully with elevation of the arm.

Which of the following is the most appropriate diagnostic study?

(A) Plain radiographs
(B) Bone scan
(C) Contrast-enhanced CT scan
(D) MR angiography
(E) Contrast angiography

The correct response is Option D.

In this 4-year-old boy who has a high-flow vascular malformation of the volar forearm, the most appropriate diagnostic study is magnetic resonance imaging with intravenous gadolinium, also known as magnetic resonance angiography (MRA). Noninvasive imaging studies are most appropriate in young patients with suspected vascular malformations. MRA delineates baseline tissue involvement and is used to distinguish between low-flow and high-flow lesions.

Plain radiographs are appropriate for detecting skeletal alterations resulting from vascular malformations, but would not be diagnostic. Duplex ultrasonography is a simple noninvasive technique that can define flow characteristics, but is cumbersome in young patients and cannot be used to accurately assess the degree of involvement of other soft-tissue structures. Contrast-enhanced CT scans do not provide the necessary resolution for evaluation of vascular malformations. Because contrast angiography is invasive, it is reserved for more extensive evaluation of high-flow malformations, preoperative planning, and/or superselective embolization.

References
1. Holder LE, Merine DS, Yang A. Nuclear medicine, contrast angiography, and magnetic resonance imaging for evaluating vascular problems in the hand. Hand Clin. 1993;9:85-113.
2. Upton J, Coombs CJ, Mulliken JB, et al. Vascular malformations of the upper limb: a review of 270 patients. J Hand Surg. 1999;24A:1019-1035.