Poland syndrome

The Poland syndrome refers to a congenital unilateral absence of the pectoralis major muscle/ minor muscle and is a recognised cause of unilateral hyperlucent hemithorax. 

Epidemiology

Poland syndrome is usually sporadic, although rare familial cases have been described ¹.  It is rare with an estimated incidence of 1 : 36000 - 50000 ¹.There does not appear to be a side or gender predilection.

Although rare, an association with Möbius syndrome has been described (thus Poland-Möbius syndrome) ^3,5 as well as with Morning glory syndrome ⁵ and Pierre-Robin syndrome ⁵.

Clinical presentation

The abnormality is usually evident at birth due to asymmetry of the chest and frequent and ipsilateral abnormalities, most frequently syndactyly ². Spectrum of abnormalities includes:

• aplasia or hypoplasia of
  • pectoralis major (most common)
  • pectoralis minor
  • ipsilateral 2^nd to 5^th ribs
  • ipsilateral breast or nipple
• upper limb abnormalities
  • small hand and brachysyndactyly ⁶
  • simian crease of affected extremity

Pathogenesis

No definite cause has as yet been identified, although it is thought to result from an isolated vascular insult in early gestation (involving embyonic subclavian and vertebral arteries).

Radiographic features

Mammography

May be seen as hypoplasia of the breast or of the pectoralis major muscle (thus absent on MLO view).

Chest radiograph

On CXR it is one of the classic causes for a unilateral hyperlucent hemithorax, and should be considered when asymmetry of chest is not explained by other causes.

CT / MRI

Although clinical examination usually suffices to make the diagnosis, cross-sectional imaging will elegantly outline abnormalities. 

Treatment and prognosis

The condition is benign and depending on the degree of involvement of the upper extremity may be asymptomatic. Cosmetic re-constructive surgery may be considered (e.g. breast implant).

Etymology

It was first described by Sir Alfred Poland : English surgeon (1822 - 1872) in 1841, after he dissected the body of a convict named George Elt at Guy's Hospital ^1,4

Differential diagnosis

For hypoplastic breast / absent tissue on one side on mammography, consider

• amazia : absence of breast parenchyma and 
• amastia : absence of breast tissue
  • this can occur from a an excision of a pre-puberal breast bud or from chest wall irradiation during childhood

For a unilateral hyperlucent hemithorax on a chest radiograph see >>

• differential for a unilateral hyperlucent hemithorax