Poland syndrome: identifying and treating pectoralis major hypoplasia

Poland syndrome is a rare congenital condition characterised by unilateral atrophy of the pectoralis major muscle (on one side of the chest), along with various possible malformations of the upper torso that may cause impairment of the hand, the arm or the internal organs. A range of surgical solutions can now reduce the handicap caused by these abnormalities of the chest, the same-side upper limb or the breasts. Let us look at the symptoms and causes of this malformation and at the different procedures used to correct it.

What is Poland syndrome?

Poland syndrome (PS) is a genetic condition that takes the form of total or partial agenesis of the sternocostal heads of the pectoralis major muscle, leading to underdevelopment of the chest or of the breast. This malformation usually also causes an absence of the pectoralis minor muscle (hypoplasia), resulting in a chest asymmetry. It may also be accompanied by breast agenesis, in other words a failure of one breast to develop.
The condition owes its name to Sir Alfred Poland, a British medical student who gave the first anatomical description of it in 1841, based on the dissection of a case observed at Guy’s Hospital in London.
In the vast majority of cases, the malformation is unilateral only and most often affects the right side (in 75% of cases). Poland syndrome is a relatively rare condition (between 1 and 3 cases per 100,000 births) and mostly affects men, with a ratio of roughly 2 to 3 affected boys for every 1 girl.
Poland syndrome presents varying degrees of severity depending on the number and extent of the abnormalities observed, which can affect the arm and the ribs in particular. Depending on the type of abnormalities present, three clinical forms of this condition can be distinguished:

• a mild form (classified as type 1), characterised by an isolated abnormality of the pectoral muscle;
• a partial form (classified as type 2), which involves an abnormality of the pectoral muscle combined with a malformation of the upper limb or the rib cage;
• a complete form (classified as type 3), combining abnormalities of the pectoral muscle, the upper limb and the ribs.

What are the symptoms?

The clinical signs of Poland syndrome can be quite varied and may affect the muscle, bone or cartilage tissue, for example:

• incomplete growth of the shoulder muscles (most often the right shoulder), which appears less developed than the other shoulder because of an abnormality of subclavicular formation;
• a total or partial absence of the breast (aplasia or breast hypoplasia) in affected young girls, which may also be accompanied by abnormalities of the nipple-areola complex that can be a source of major self-consciousness, particularly at an age when self-image matters greatly. This is referred to as chest asymmetry;
• in children, Poland syndrome can take the form of more or less severe abnormalities of the upper limbs, which are then less developed than average (underdeveloped hands, fingers that are too short, or brachydactyly);
• Poland syndrome can also cause syndactyly, that is, the fusion or joining of the fingers (webbed fingers), which leads to the formation of « webbed digits » that can be particularly disabling and a source of daily self-consciousness;
• endocrine problems due to a dysfunction of the glands responsible for releasing hormones (fatigue, sexual disorders, nervousness, etc.);
• in the most severe cases, Poland syndrome can hinder the normal development of a number of organs (intestines, liver, ribs, diaphragm, gallbladder and even the heart), which then take up unusual positions. In rare cases the heart may, in particular, be located on the right (dextrocardia). These unusual placements, when limited to agenesis of the pectoralis major, cause no physical pain and no functional problem, as the other muscles (notably the trapezius or the latissimus dorsi) compensate. The absence of one or more ribs may, however, cause abnormal breathing.

How does Poland syndrome present in men?

Because the condition affects two to three times more boys than girls, Poland syndrome is one of the main causes of pectoral malformation in men. Agenesis of the pectoralis major on a single side creates a visibly asymmetrical chest: normal muscle definition on one side, and a hollow on the other in the upper part of the torso, beneath the collarbone. This absence of a pectoral muscle is often accompanied by an areola that is smaller, set too high and too far to the outside compared with the healthy side, with the nipple also appearing displaced.
Unlike simply poor pec genetics (where both muscles are present but poorly developed) or a muscular asymmetry that can be corrected through weight training, the hollow of Poland syndrome corresponds to a muscle that is genuinely absent: no amount of muscle-building can rebuild it. In men, correcting this misshapen torso therefore relies on fat transfer (lipofilling) and/or a custom-made implant to restore the contour of the pectoral muscle. When the asymmetry of the male chest is due to an excess of gland tissue rather than an absent muscle, the appropriate option is instead gynecomastia surgery: an assessment by the surgeon makes it possible to tell the two situations apart.

What are the causes of pectoral muscle atrophy?

The reasons behind Poland syndrome remain poorly understood and documented to this day. Although a genetic or embryonic origin is most often suspected, some studies have also suggested that it could result from blood-flow problems during pregnancy, with in particular poor vascularisation and atrophy of the arteries and veins that should carry blood to the pectoralis major muscle (the so-called subclavian artery interruption hypothesis, occurring around the sixth week of pregnancy).
The results of further studies have also shown that Poland syndrome could be attributed to a malformation of the rib cage during pregnancy.
Other studies further suggest that certain factors may increase the risk of congenital abnormalities such as Poland syndrome. This is the case in particular with:

• a family history of malformations;
• alcohol or drug use during pregnancy;
• a history of pregnancy complications such as gestational diabetes or exposure to chemical substances;
• a history of multiple pregnancy.

In some cases, Poland syndrome is caused by a genetic mutation passed on through autosomal inheritance (inherited from a single parent). Most often, however, the condition occurs sporadically, with no history found among the affected person’s family members: the risk of passing it on to one’s children therefore remains, in the vast majority of cases, very low.

Poland syndrome: diagnosis

A diagnosis of Poland syndrome is generally made at birth, because of the chest malformation visible to the naked eye. It is not, in fact, visible beforehand on prenatal ultrasound scans. At birth, in addition to the clinical examination, further imaging tests such as a chest X-ray, an MRI or an abdominal ultrasound may be carried out to determine the extent of the abnormality. They may also be used to rule out the possible presence of other conditions liable to cause similar symptoms, in particular neurological abnormalities.
In the mildest forms (type 1), where only the pectoral muscle is involved, the asymmetry may nevertheless go unnoticed in early childhood and only be spotted in adolescence, when the chest develops or when the breast, in a young girl, fails to form symmetrically.

What surgical solutions are there to treat this chest malformation?

Treatment of Poland syndrome relies mainly on plastic and reconstructive surgery techniques. To achieve convincing results, 2 to 3 procedures are generally performed at intervals of 3 to 6 months.

Plastic surgery to treat Poland syndrome

Cosmetic surgical procedures are carried out once growth is complete and aim to reconstruct or increase the volume of the breasts and the pectoral muscles, allowing teenagers to put their self-consciousness behind them. They consist mainly of 2 techniques:

• the placement of a breast implant, which involves positioning a breast implant made of silicone gum or elastomer that mimics the natural shape of the breast. The procedure takes place under general anaesthesia and the implant is usually custom-made with the help of 3D scanning (computer-aided design and manufacturing) so that it matches the chest perfectly and thus puts an end to the breast asymmetry. A breast augmentation with a custom-made implant can be supplemented by a fat graft to refine the result still further;

• performing a breast lipofilling using autologous fat transfer under general anaesthesia. This technique involves harvesting fat cells by liposuction from areas of the patient’s body where there is an excess (belly, hips, buttocks, knees, etc.) in order to reinject it into the underdeveloped breast after a centrifugation process designed to remove the fibrous residue. This biocompatible technique allows a precise breast reconstruction with very natural results. Fat grafting can also be used to complement the placement of a breast implant, in order to conceal the edges of the implant and fill the persistent hollow between the collarbone and the shoulder (the acromial junction). The aim is then to achieve symmetry with the opposite breast.

Other, less common solutions may nevertheless be used in specific cases. This is true, for example, of:

• reconstruction of the areola by means of a skin graft;
• tucking the latissimus dorsi flap under the skin of the chest;
• the use of a free flap to build up the chest;
• a symmetrising breast plasty;
• the use of skin expanders.

It should be noted, finally, that whatever procedure is carried out on the chest, it will have no functional purpose and will be purely morphological (it will not improve shoulder mobility). To overcome a functional problem, compensatory muscle-strengthening exercises will often be needed, with the help of a physiotherapist.

Reconstructive surgery to treat functional malformations

To correct malformations of the upper limbs, surgery can also be performed from a very young age. The first hand operations can in fact be carried out on children aged 6 to 12 months. It is then possible to separate fused fingers, provided their shape does not make the operation impossible (toe-phalanx grafts are now available for the most severe malformations). The operation will not enlarge the hand but will give the fingers the chance to develop normally during the child’s growth, thereby avoiding functional problems.
As for malformations of the rib cage, these generally improve with age and rarely require surgery. Breathing exercises and muscle strengthening of the arms and chest usually help to improve any breathing problems that may arise from Poland syndrome. Patients of this kind will, however, need to be monitored to prevent a possible progression towards scoliosis and to provide the appropriate treatment if necessary.

Care and support

Poland syndrome is a recognised congenital malformation: correcting it falls under reconstructive surgery rather than a purely cosmetic procedure. On that basis, some of the procedures may qualify for insurance coverage from the French national health insurance, subject to prior authorisation and depending on the severity of the condition. Care is by nature multidisciplinary: it brings together the plastic surgeon, sometimes the hand surgeon, and psychological support, since the impact of the condition on self-image is often at least as heavy as its physical consequences. Beyond the morphological result, patients report a major psychological benefit after correction, with a clear improvement in confidence and self-esteem.