An unusual case of the congenital mesenchymal hamartoma of the neck associated with the midline cervical cleft in neonate.

Objectives: Hamartomas are non-neoplastic developmental anomalies, mostly congenital, characterized by uncontrolled, disorganized proliferation of local endogenous tissue, which can normally be found at the site of origin and are very often mesodermally derived. It is well known that hamartoma can be associated with congenital midline cervical cleft and therefore cause a variety of symptoms. In general, they are benign and indolent, but they can be the cause of complex morbidity if they are localized within specific regions, such as the head and neck, which represent highly sensitive and vulnerable areas. Case presentation: The reported case is unusual because of the presence of a congenital mesenchymal hamartoma along with the median cervical cleft, in a 1-day-old neonate, without the presence of any respiratory symptoms or associated congenital features. Although extremely rare, hamartomas should be included in the differential diagnosis of congenital neck masses, with emphasis on diagnostic approach, to avoid overly aggressive treatment and possible complications, such as infection, further mass growth, malignant transformation and compression of the adjacent neck structures. Conclusions: Appropriate and timely treatment of the hamartoma of the neck in neonates, with further follow-up is necessary to avoid an overly aggressive treatment and to distinguish benign from malignant lesions, which is necessary for successful curative outcome.