Sindromul Poland - prezentare de caz şi review al literaturii

Introduction

The Poland syndrome is a rare congenital disorder that consists of unilateral agenesis or underdevelopment of pectoralis major muscle associated with thoracic and/or variable ipsilateral upper limb anomalies^(1,2).

The disease is estimated to occur in 1 to 3 per 100.000 newborns^(3,4). Poland syndrome tends to affect more male patients than female patients, with a ratio of 3:1, and in 75% of the cases the anomalies are present on the right side^(4,5,6).

Anomalies

In 1981, Poland reported a case of unilateral absence of the pectoralis major muscle in an individual who also had cutaneous syndactyly of the hand on same side. Since then, this syndrome has incorporated other associated anomalies such as^(6,7):

• Thorax: hypoplasia or absence of nipple and areola (athelia), agenesis of costal cartilages and rib cage diformities^(6,7,8), aplasia of one breast and underlying subcutaneous tissue in females, elevation of the shoulder blade (Sprengel deformity)^(2,8).
• Upper limb: shortening of the arm, underdevelopment of the forearm bones, varying degrees of syndactyly^(1,2,6). Some studies state that 10% of patients with syndactyly have other abnormalities of the Poland syndrome⁽⁶⁾.
• Hemivertebrae⁽⁶⁾.
• Dermatologic anomalies include: pectoral and axil­lary alopecia, absence of sweat glands and anhidrosis⁽⁹⁾.

In some rare cases, the disease is more severe and complex, and individuals have abnormalities of internal organs such as dextrocardia, diaphragmatic hernia and renal alterations^(2,3).

There have been described in the medical literature associations of Poland syndrome with Moebius syndrome (neurological disorder which is characterized by facial paralysis and the inability to move the eyes from side to side⁽¹⁰⁾), facio-auriculo-vertebral dysplasia and fronto-nasal dysplasia⁽⁴⁾.

Also, hematopoietic malignances like non-Hodgkin lymphoma and leukemia have been observed in Poland syndrome patients^(11,12).

Presentation

Although it is a congenital disorder, in mild cases without hand involvement, Poland syndrome may not be evident until puberty, when the differences between the left side and the right side of the chest become more evident⁽³⁾.

The physical examination has to determine the grade of breast and latissimus dorsi development. A useful maneuver is asking the patient to strain downward with his or her hand on the hip.

Also, extraocular muscle motion must be confirmed for excluding an associated Mobius syndrome.

The chest abnormalities may also require a radiograph of the torax or a CT-scan.

Lymph node examination and blood-cell count should assist the evaluation in order to discover a possible hematologic malignancy⁽¹¹⁾.

Etiology

The disease is defined as a “non-specific developmental field defect”⁽⁸⁾. The current hypothesis is that it occurs around the 6^th week of fetal development and is caused by a diminished or disrupted blood flow of the subclavian artery proximal to the origin of the thoracic artery but distal to the origin of vertebral artery. This way, it appears to be a deficiency of blood supply in the pectoral region and into the upper limb and therefore results into a partial loss of tissue in these regions^(6,8). This diminished arterial supply affects fetal growth at about the 46^th day of pregnancy, when the fetal fingers and pectoralis muscle are developing⁽⁸⁾.

The vascular event, known as subclavian artery supply disruption sequence (SASDS), occurs when the medial and forward growth of the ribs forces the subclavian vessel to take a U-shaped configuration⁽⁴⁾.

Another possible cause is stated by Martinez-Friaz et al. (1999) in a study that observed in smokers a two-fold higher risk of having Poland syndrome newborns due to the vasoactive properties of tobacco smoke that can produce congenital defects related to vascular disturbances⁽¹⁰⁾.
 

Most cases are sporadic, but there are several studies that suggest some degree of genetic transmission^(5,11). Different inheritance patterns have been observed in a study performed in 120 patients with Poland syndrome.

There were identified 14 rare copy number variations (CNV) in regions different from the common CNVs. There were seven genomic duplications and seven genomic deletions. These CNVs ranged from 0.04 to 4.71 Mb in size and the bioinformatic analysys of array-Comparative Genomic Hybridization data showed over-represented genes in different pathways involved in DNA binding, cell-adhesion, apoptosis. The analysis found a number of possible genes generating the anomalies of Poland syndrome patients and therefore these CNVs may represent risk factors or may contribute to Poland syndrome inheritance⁽⁵⁾.

Treatment

Because in most cases the functional disability is mild, the patients usually present later for evaluation and discussion on esthetic options. They usually require surgical treatment for chest deformity and breast asimmetry. The surgical options and timing of the intervention depend on breast development, degree of chest wall deformity and the existence of latissmus dorsi.

If breasts are not fully developed, the hypoplastic breast can be incrementally expanded with a temporary tissue expander implant placed subcutaneously since pectoralis muscle is absent, in order to match the unaffected breast development.

When the breast growth ends and the breast envelope is sufficiently stretched, the latissimus dorsi muscle can be used for reconstruction with or without a permanent implant, depending on the desired size. Latissimus muscle can be used to correct the absence of axillary line, and the infraclavicular flattening and can also provide subcutaneous filler to cover the edge of implant. On patients with minor assimetry of breast, a permanent implant expander correction can be performed (e.g., Becker implant)⁽¹¹⁾.

Regarding male patiens, the chest deformity can be corrected with latissimus dorsi flap since the age of 13-years-old⁽¹¹⁾.

Case report

We present the case of a full-term (39 weeks) newborn Romanian female, after a caesarian section performed in “St. Pantelimon” Emergency Hospital from Bucharest, with unilateral breast and chest wall asimmetry, along with upper limb abnormalities, located on the left side.

The parameters at birth were as follows: birth weight - 2660 g, length - 48 cm, head circumference - 33 cm, chest perimeter - 30 cm, and Apgar score - 9/10.

The mother was a non-smoker, primiparous and there was no family history of congenital malformations, syndromes or consanguinity.

The clinical examination of the thorax revealed left-right asymmetry, with congenital absence of the left pectoralis major muscle and agenesis of the left breast with associated athelia (Figure 1). The newborn had no breathing difficulties and the cardiovascular parameters were normal. Another abnormality was found in the left upper limb, as the patient was born with partial cutaneous syndactyly involving the third and the fourth fingers of the left hand.

The patient had a chest radiograph which showed the absence of the anterior costal arches from T3 to T10 vertebrae (Figure 2).
 

Discussion

Poland syndrome is a rare congenital disorder that in most cases is sporadic. Although recent genetic studies sustain the theory that there are several genes involved in different inheritance patterns, in our case the Poland syndrome occurred as a sporadic event as there was no evidence of congenital malformations in the patient’s family. However, taking into account this was the first newborn, future pregnancies of the same mother should be observed, because of the possibility of similar malformated newborns.

A particularity of this case is that the newborn is a female, despite the fact that in Poland syndrome males predominate by at least 3:1. Also, the patient had all the developmental anomalies located on the left side of the body, which represent 25% of the overall cases. Therefore, the rarity of this case increases significantly.

The risk factors remain unknown for this case, as there was no additional risk of Poland syndrome caused by smoking, since the mother had neither a history of smoking, nor has been passively exposed to cigarette smoke on long term.

We have to take into consideration that the patient is a newborn and that clinical manifestations of the disease may appear later in time, along with hematologic complications, so a close follow-up of the case has to be done for preventing sever alterations of the quality of life. The proper time for surgical reconstruction has to be carefully and multidisciplinary selected in order to achieve the best result.

Conclusions

We presented the case of a sporadic Poland syndrome in a Romanian female newborn, a very rare congenital disorder that involved the left side of the chest wall and left hand, which is an uncommon site of involvement, also with rib cage abnormalities but no respiratory or cardiac complications. However, the symptoms and complica­tions may occur later in time, therefore surgical treatment is not yet necessary, but will be taken into consideration at a proper age.