PP-029 Poland syndrome manisfesting as defective pectoralis major muscle and dextroscoliosis: a case report

Poland syndrome is a rare congenital anomaly of unknown etiology, with variable clinical manifestations. Classically, there is predominantly, unilateral aplasia or hypoplasia of the sternocostal head of the pectoralis major muscle and ipsilateral brachysyndactyly. Through this case report, we want to elaborate on the hypothesized origin, clinical presentation, and classification of Poland syndrome. The case report will also highlight the atypical presentation of ipsilateral absence of pectoralis major muscle without classical hand deformity in a female neonate.

We report the case of a newborn, female, outcome of normal vaginal delivery, born to 28 years old, gravida 5, parity 4, O positive mother at 38 weeks of gestation. Mother was unbooked, not investigated and did not go for regular antenatal visits. There is no history of consanguinity or maternal drug use during pregnancy. Baby had cried immediately after birth and the Apgar score at 1 and 5 minutes were 8 and 9 respectively. Baby weighed 3.2 kg at birth (50th - 90th percentile), length 51 cms (90th - 97th percentile), and head circumference 35.5 cms (90th percentile). Delivery room examination revealed asymmetric chest contour, with depression on the right side of the chest, and flattening of right pectoral region. No other obvious congenital malformation was detected.

Chest X-ray was suggestive of clear lung fields and relatively, mild dextroscoliosis with lower thoracic and upper lumbar level involvement. Cranial and abdominal ultrasonography were unremarkable. Echocardiography was normal. MRI and ultrasonography chest reported non-visualization of the right-sided pectoralis major muscle. Hence, a diagnosis of Poland syndrome involving right hemithorax in a female neonate was established.

Poland syndrome was first described by Alfred Poland in the year, 1840-1841. The incidence stands at 1:30,000, with a male preponderance. Classically, there is predominantly, unilateral aplasia or hypoplasia of the sternocostal head of the pectoralis major muscle and ipsilateral brachysyndactyly. Right hemithorax is involved in seventy five percent of the unilateral cases. Bilateral involvement of pectoralis major muscle have been infrequently reported in the literature. Other anomalies described include renal, vertebral, breast, anterior chest wall and lower limb malformation as well as lung herniation and dextrocardia. Vascular etiology has been hypothesized, wherein there is an interruption in the circulation of the subclavian and vertebral arteries during 6 weeks of gestation, a period associated with splitting of the two heads of pectoralis major and the development of tissues between the digits. There are also studies that have linked development of Poland syndrome to exposure to ergot alkaloids during the first trimester of pregnancy.