Poland syndrome is a disorder in which affected individuals are born with missing or underdeveloped muscles on one side of the body, resulting in abnormalities that can affect the chest, shoulder, arm, and hand. The extent and severity of the abnormalities vary among affected individuals.
Poland syndrome has been estimated to occur in 1 in 20,000 newborns. For unknown reasons, this disorder occurs more than twice as often in males than in females. Poland syndrome may be underdiagnosed because mild cases without hand involvement may never come to medical attention.
Poland syndrome is a birth defect characterized by an underdeveloped chest muscle and short webbed fingers on one side of the body (1). Short ribs, less fat, and breast and nipple abnormalities may also occur on that side (2). Typically the right side is involved. People generally have normal movement and health.
The cause is unknown. One theory is that it is due to disruption of blood flow during development before birth. The condition is generally not inherited from a person’s parents. No genes that contribute to the disorder have been identified. Diagnosis is based on symptoms. Often people remain undiagnosed and some may not realize they are affected until puberty (1).
Treatment depends on the severity and may include the surgical correction. About 1 in 20,000 newborns are affected. Males are affected twice as often as females. It is named after Alfred Poland, who described the condition when he was a student in 1841 (3).
Mild cases of Poland syndrome without hand involvement may not be evident until puberty when the differences (asymmetry) between the two sides of the chest become more apparent. By contrast, severely affected individuals have abnormalities of the chest, hand, or both that are apparent at birth. In rare cases, severely affected individuals have abnormalities of internal organs such as a lung or a kidney, or the heart is abnormally located in the right side of the chest (dextrocardia).
Rarely, chest and hand abnormalities resembling those of Poland syndrome occur on both sides of the body, but researchers disagree as to whether this condition is a variant of Poland syndrome or a different disorder.
Causes
The cause of Poland syndrome is unknown. Researchers have suggested that it may result from a disruption of blood flow during development before birth. This disruption is thought to occur at about the sixth week of embryonic development and affects blood vessels that will become the subclavian and vertebral arteries on each side of the body. The arteries normally supply blood to embryonic tissues that give rise to the chest wall and hand on their respective sides. Variations in the site and extent of the disruption may explain the range of signs and symptoms in Poland syndrome. Abnormality of an embryonic structure called the apical ectodermal ridge, which helps direct early limb development, may also be involved in this disorder.
Rare cases of Poland syndrome are thought to be caused by a genetic change that can be passed down in families, but no related genes have been identified.
Genetics
Most cases of Poland syndrome are sporadic, which means they are not inherited and occur in people with no history of the disorder in their families. Rarely, this condition is passed through generations in families. In these families the condition appears to be inherited in an autosomal dominanace pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder, although no associated genes have been found.
Other Names for this Condition
- Poland anomaly
- Poland sequence
- Poland syndactyly
- Poland’s anomaly
- Poland’s syndrome
- Unilateral defect of pectoralis major and syndactyly of the hand
Treatment
Technique
The complete or partial absence of the pectoralis muscle is the malformation that defines Poland syndrome. It can be treated by inserting a custom implant designed by CAD (computer-aided design) (4). A 3D reconstruction of the patient’s chest is performed from a medical scanner to design a virtual implant perfectly adapted to the anatomy of each one. The implant is made of medical silicone unbreakable rubber. This treatment is purely cosmetic and does not make up for the patient’s imbalanced upper body strength.
The Poland syndrome malformations being morphological, correction by custom implant is the first-line treatment. This technique allows a wide variety of patients to be treated with good outcomes. Poland Syndrome can be associated with bones, subcutaneous and mammary atrophy: if the first, as for pectus excavatum, is successfully corrected by a custom implant, the others can require surgical intervention such as lipofilling or silicone breast implant, in a second operation.
Surgery
The surgery takes place under general anesthesia and lasts less than 1 hour. The surgeon prepares the locus to the size of the implant after performing an 8-cm axillary incision and inserts the implant beneath the skin. The closure is made in two planes.
The implant will replace the pectoralis major muscle, thus enabling the thorax to be symmetrical and, in women, the breast as well. If necessary, especially in the case of women, a second operation will complement the result by the implantation of a breast implant and/or lipofilling.
Lipomodelling is progressively used in the correction of breast and chest wall deformities. In Poland syndrome, this technique appears to be a major advance that will probably revolutionize the treatment of severe cases. This is mainly due to its ability to achieve the previously unachievable quality of reconstruction with minimal scarring.
References
- Poland syndrome. Genetic and Rare Diseases Information Center (GARD) – an NCATS Program (2016).
- Poland syndrome. Genetics Home (9 October 2018).
- Poland Syndrome. NORD (National Organization for Rare Disorders) – 2007.
- Annales de Chirurgie Plastique Esthétique. 55: 471–480.
