Continuing Education Activity

Poland syndrome consists of anatomic anomalies that include the absence of the sternocostal head of the pectoralis major muscle with other varied manifestations that include hypoplasia or absence of the pectoralis minor muscle as well as digital anomalies such as syndactyly. Other anomalies include the absence or hypoplasia of the ipsilateral breast, excavatum deformities, and rib aplasia. Defects are overwhelmingly unilateral and more commonly affect the right side. This activity reviews the cause, presentation of Poland syndrome and highlights the role of the interprofessional team in its management.

Objectives:

• Describe the physical features of Poland syndrome.
• Review the work up of a patient with Poland syndrome.
• Outline the treatment and management options available for Poland syndrome.
• Describe interprofessional team strategies for improving care coordination and outcomes in patients with Poland syndrome.

Introduction

Poland syndrome consists of anatomic anomalies that include the absence of the sternocostal head of the pectoralis major muscle with other varied manifestations that include hypoplasia or absence of the pectoralis minor muscle as well as digital anomalies such as syndactyly.[1] Other anomalies include the absence or hypoplasia of the ipsilateral breast, excavatum deformities, and rib aplasia.[1] Defects are overwhelmingly unilateral and more commonly affect the right side.[2] Bilateral manifestations, although exceedingly rare, have also been described.[3] Many variations of the syndrome have been described, from mild hypoplasia of the pectoralis major musculature to severe hypoplasia of the thoracic wall.[4] Upper limb defects also vary from mildly syndactyly to severe brachysyndactyly.[4][1]

Etiology

The etiology of Poland syndrome is not well understood and is thought to arise from abnormalities relating to the subclavian arteries and branch vessels during embryogenesis, reducing perfusion to the affected ipsilateral side of the chest wall.[5] Findings of vascular hypoplasia of the subclavian vessels and branch vessels support this etiology, suggesting hypoperfusion of the developing limb bud during embryogenesis as the cause of Poland syndrome.[5] A teratogenic etiology has also been suggested because research shows an association with maternal smoking and cocaine use.[6][7] History of misoprostol administration has been implicated.[8]

Epidemiology

Poland syndrome affects about 1 in 36,000 to 50,000 newborns, with males more likely to be symptomatic than females.[9] Furthermore, right-sided predominance occurs more frequently in men than women.[10] Cases usually are sporadic, with rare familial cases also described in the literature.[11] Given the likelihood that Poland syndrome is often underdiagnosed and under-reported, the exact incidence is not definitively known, and incidence rates are usually estimated.[12]

History and Physical

Patients with Poland syndrome usually present for cosmetic and aesthetic complaints and are usually asymptomatic.[13] In pediatric patients and cases with more severe deformities, a more thorough history and physical examination are warranted. Patient history of cardiopulmonary complaints, although rare, can be important given the association of dextroposition and lung herniation with Poland syndrome.[10][14]

The physical evaluation for Poland syndrome includes an assessment of the anterior chest wall and associated anatomic limb abnormalities.[15][16] Evaluation of the anterior chest wall includes palpation to asses for asymmetry of the chest wall musculature as well as evaluation for osseous and cartilaginous deformities of the rib cage.[17] Evaluation for absence or hypoplasia of the costosternal pectoralis major muscle and the pectoralis minor muscle can usually be diagnosed with visual inspection and palpation.[18] Overlying soft tissues of the chest wall also tend to be thinner than normal.[1] Nipple absence or hypoplasia is frequently seen, and regional alopecia of the anterior chest wall and axilla can often be appreciated.[19] Breast asymmetry and hypoplasia, including a higher position of the breast of the affected side, can be seen in female patients.[20] Physical examination to evaluate the muscular caliber of the serratus, latissimus dorsi, and trapezius should be performed as hypoplasia of these muscles can also be present.[21] Evaluation of the latissimus dorsi is important, especially in the setting of a planned surgical intervention.[21] A cardiopulmonary examination to evaluate for dextroposition, especially in the setting of left-sided Poland syndrome, should also be performed.[22]

Visual inspection and the physical examination of the ipsilateral limb is important because those limb anomalies are present in most cases, specifically syndactyly; hypoplastic metacarpals and phalangeal abnormalities of the index, middle, and ring fingers most commonly affected.[23] In a pediatric patient, the association with Klippel-Feil and Mobius syndromes warrants a physical examination to evaluate for other manifestations including abnormalities of the cervical spine and craniofacial abnormalities should be performed.[24][25]

Evaluation

Prenatal sonographic evaluation can demonstrate unilateral limb defects and unilateral chest wall asymmetry and should prompt evaluation for other associated anatomic defects.[26] In an adult patient, although physical examination is usually sufficient in the diagnosis of Poland syndrome, further evaluation with CT can be performed, especially in the setting of surgical planning or further evaluation for associated cardiopulmonary abnormalities to include lung herniation.[27] On mammogram, hypoplasia of the unilateral breast and hypoplasia of the pectoralis major are often appreciated.[28] Chest radiograph findings of a unilateral hyperlucent thorax are classically seen. Ultrasound of the chest wall can also be used to evaluate for defects of the pectoralis major and minor musculature.[29]

Treatment / Management

Surgical intervention, although rarely necessary, can be indicated for reasons including paradoxical movement of the chest wall, hypoplasia or aplasia of the female breast, and cosmetic indication for men and women with chest wall asymmetry.[30] Chest wall reconstruction in the setting of severe rib hypoplasia and aplasia can also serve as an operative indication.[30] The operative course varies and depends on the degree of deformity as well as the patient’s age and gender.[31] Usual operative strategies include a muscle flap as well as breast augmentation in women.[23] Bone grafts can be used in the setting of sternal and rib defects.[30] Given that the ipsilateral latissimus dorsi muscle can potentially be hypoplastic in a patient with Poland syndrome, the contralateral latissimus dorsi muscle would serve as the next viable option for a muscle flap procedure.[32] Syndactyly release can usually be performed in a pediatric patient without significant complications and can be performed with or without a skin graft.[33]

Differential Diagnosis

Differential diagnosis of Poland syndrome in female patients includes normal breast asymmetry.[34] Although not usually necessary, further evaluation with imaging to include CT can help differentiate breast asymmetry secondary to Poland syndrome by evaluating the anatomy of the pectoralis major muscle.

An incidentally noted absent pectoralis muscle on CT scan could also be secondary to a surgically absent pectoralis major muscle.[35] In the setting of an incidentally noted radiograph finding of a unilateral hyperlucent hemithorax, the differential diagnosis includes airway obstruction, Swyer-James syndrome, a mastectomy, a unilateral large bullae, and pneumothorax.[36]

Complications

The majority of patients with Poland syndrome are asymptomatic and have few functional manifestations.[37][38] Prognosis usually depends on the degree of surgical intervention performed and varies depending on the severity of the syndrome. Complications that have been described in the literature usually are not different from similar procedures done for other indications.[39]

Enhancing Healthcare Team Outcomes

In the setting of asymptomatic cases, a primary care physician and a radiologist often are the sole members of the healthcare team involved in diagnosing and educating the patient on this presenting complaint. In the setting of planned surgical intervention, a primary care physician often in coordination with a surgeon, is involved in assessing the patient's health status before surgery.[40] A radiologist can potentially play a role in assisting a surgeon on the degree of hypoplasia and absence of the pectoralis muscles as well as the degree of hypoplasia of the latissimus dorsi; this often can help guide surgical approach based on the degree of severity.[41] In the setting of severe cases of aplasia of the chest wall, a coordinated approach between a pulmonologist, a radiologist, and a cardiothoracic surgeon is important in guiding reconstruction as well as post-surgical follow up.