Bronchogenic cysts are rare congenital malformations that result from abnormal budding of the tracheobronchial tree.

During embryonic development, the primitive foregut appears during the third week of gestation and divides into a dorsal portion, which elongates to form the esophagus, and a ventral portion, which differentiates to form the tracheobronchial tree. Errors in the development of the ventral foregut will result in bronchogenic cysts [1,2]. The developmental stage at which these errors occur determines the final location of the bronchogenic cysts [3]. Cutaneous presentations of these cysts are rare and are seen shortly after birth or in infancy [3]. They preferentially affect young male children and present clinically as exophytic lesions on the skin with most often the presence of fistulas. The most frequent location is the preseternal area [4].

Dermoscopic description of this entity has never been described to date. We report the case of a 2-month-old infant with no previous pathological history who presented with a rounded papule of normal skin colour measuring about 1 cm in diameter on the right lateral aspect of the neck resting on a slightly atrophic and scaly plaque with a small pertus at its lower part. Dermoscopic examination revealed an erythematous background, yellowish scales, a few leucotrichic hairs and coarse round whitish structures as well as a few linear vessels. The diagnosis of bronchogenic cyst is based on anatomopathological examination of the lesions with standard hematoxylin and eosin staining. The cyst wall is formed of smooth muscle and sometimes cartilage and shows tracheobronchial differentiation with a respiratory-type epithelium that includes columnar cells, ciliated cells, and mucus-secreting cells [4]. These cysts may be lined with fibrous tissue. Immunohistochemical study shows CK7 labelling with negativity for TTF-1, CDX-2 and CK20 in favour of a bronchogenic origin [5]. The round whitish structures may correspond histologically to cystic structures lined with fibrous tissue and smooth muscle, the linear vessels may be correlate to inflammation or vasodilatation of dermic vessels (Figures 1,2).

Figure 1: Clinical picture of a cutaneous bronchogenic cyst.