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Figure 1. The left breast, areola, and nipple are absent.

Alfred Poland¹ described unilateral absence of the pectoralis major, serratus anterior, and abdominal external oblique muscles on autopsy examination of a 27-year-old man who also had cutaneous syndactyly of the hand on the same side. The syndrome that carries his eponym has been expanded, but it most commonly refers to the association of a congenital unilateral absence of the pectoralis major muscle and syndactyly of the ipsilateral upper extremity.

The constitutive mark of the condition is the absence of the pectoralis major muscle, present in 100% of the cases.² In a series of 599,109 live births, a unilateral pectoralis major muscle defect was found in 27 neonates, 12 of whom also had hypoplasia and/or syndactyly of the ipsilateral hand.³ The incidence of Poland syndrome is estimated to be approximately 1 in 20,000, with about 10% of patients with syndactyly demonstrating features of the syndrome.⁴ More than 75% of the defects associated with this syndrome are present on the right side.⁵

In addition to the muscle abnormalities, other chest findings may include underdevelopment or absence of the breast and nipple-areola complex; abnormalities of the anterior ribs, clavicle, and scapula; axillary bands or webs; and lung herniation.⁶ Upper-extremity abnormalities reported with this syndrome include brachydactyly and syndactyly, absent phalanges or digits, and hypoplasia of the forearm, wrist, or hand.^2,4,6 Additional defects reported sporadically include hemivertebrae, renal anomalies, dextrocardia, and Sprengel deformity.

In his 1841 autopsy note, Poland¹ referred to the hypoplastic appearance of the thoracic vessels supplying the intercostal spaces. Others have postulated that the underlying cause of this disorder is a congenital vascular maldevelopment in which arterial vasospasm or vessel malformation could result in hypoxia to one side of the fetus as the limb bud develops adjacent to the chest wall.⁷ Bouvet et al⁸ described stenosis of the left subclavian artery in a child with Poland syndrome affecting the left side and demonstrated a consistent decrease in the velocity of systolic blood flow to the affected side. Galvango et al⁹ described internal thoracic artery hypoplasia in another patient with this syndrome.

Intrauterine insults, resulting in the formation of thrombi or thrombotic emboli within the placenta, have also been suggested as a cause of Poland syndrome.⁶ Vasospasm induced by various drugs has also been postulated as a possible mechanism of inducing adverse effects on the developing fetus.¹⁰ An inheritable component to Poland syndrome may also exist. Darian et al⁶ described a family in which 3 women had absence of the right pectoralis major muscle and hypoplasia of the ipsilateral breast, and 2 men had hypoplasia or agenesis of the right pectoralis major muscle. Although none of the family members had upper-limb abnormalities, the other features were felt to be consistent with Poland syndrome, making this the 14th known family with this disorder described in the world literature.

Most patients with Poland syndrome do not require surgical procedures to correct muscle or chest wall deformities. Breast reconstruction and augmentation should be considered after full development for women with amastia or hypoplasia of the breast. Latissimus dorsi muscle flaps have been used in the reconstruction of absent pectoralis major muscles.¹¹ Surgical treatment of syndactyly and other hand anomalies generally improves functional capacity and cosmetic appearance.

Accepted for publication March 16, 1999.

Corresponding author: James Edmiston, MD, Department of Family Medicine, North Shore Hospital, Miami, FL 33125.