Nasal chondromesenchymal hamartoma of infancy clinically mimicking meningoencephalocele.

We report a typical case of nasal chondromesenchymal hamartoma (NCMH) of infancy, which extended to the orbit and intracranium through the skull base. The nasal mass was incidentally found in a 5-month-old otherwise healthy boy who had recently developed ptosis of the left eye. On neuroimaging, there were defects in the left ethmoid bone of the anterior cranial fossa and medial orbital wall. A round heterogeneous mass was found in the left nasal cavity. Solid portions were strongly enhanced. The preoperative diagnosis was nasal glioma or encephalocele. After frontal craniotomy, the mass was separated from the cranial basal dura. Through the transnasal approach, the mass was dissected from the left orbital content and removed. NCMH is a rare benign lesion and histopathological analogue of the mesenchymal hamartoma of the chest wall, having unique pathology: islands of hyaline cartilage, somewhat calcified or ossified hyalinized collagenous trabeculae and abundant myxoid stroma. Its occurrence in the nasal cavity was identified in 1998. The recognition of this entity is necessary to avoid misdiagnosis of the frozen section and for appropriate surgery.