This article goes through the fairly specific and unique condition of paediatric midline nasal dermoids. It goes through the epidemiology and then the embryology, reminding the reader that a protrusion of dura extends from the anterior cranial fossa through the foramen cecum, traversing the prenasal space, and apposes ectoderm at the site of the future rhinion. When the frontal and nasal bones subsequently fuse, the dural diverticulum involutes. Where exactly the regression fails would then determine whether a cyst, sinus or tract results. They are typically midline and can be found anywhere between the glabella and the columella. If inferior, they splay the lower lateral cartilages, widening the nose. They are firm, non-compressible and do not transilluminate (cf. encephalocele/glioma). A positive Furstenberg test is where the IJV is occluded and if the lesion enlarges, this is then an encephalocele. The lesion characteristically has a hair-lined tract, ending in a pit – if a hair protrudes from this then it is pathognomic for a dermoid. CT and MRI are the best modalities to help differentiate between differential diagnoses. Surgical technique is then determined on the site and presence of intracranial extension. These include open frontal craniotomy; rhinoplasty and direct excision through nasal dorsum incision; endoscopically assisted rhinoplasty or transnasal. Each technique is accompanied by a description of the steps and clinical photographs. Line drawings of the embryological process would have enhanced this interesting article further.
Nasal dermoids
Reviewed by Suzanne Jervis
Surgical management of nasal dermoid lesions.
CONTRIBUTOR
Suzanne Jervis
FRCS (ORL HNS), Shrewsbury and Telford Hospitals, NHS Trust, UK.
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