A 9 year old female patient who from the age of 3 years presented with protrusion at the level of the nasal root. In the last year, prior to admission, an increase in this deformity was detected, which caused cosmetic alterations and anxiety with schooling problems.
Physical examination revealed only a frontal bulge over the nasal root, with no pain on palpation or other relevant pathological findings.

Cranial computed tomography (CT) and magnetic resonance imaging (MRI) showed deformity of the frontal sinus, with no occupation of the sinus; sinus walls of normal thickness. No intracranial lesions were found. There was also a concomitant right parietal lesion compatible with fibrous dysplasia.

The hormonal study revealed levels within the normal range for her age.
The patient underwent surgery and a coronal incision was made, exposing the frontal bone and nasal root and revealing a bulging of the frontal sinus. Multifragmentation and remodelling of the anterior wall of the sinus was performed, preserving the mucosa, using an ultrasonic scalpel. The bone defect was reconstructed with resorbable mesh (polylactic and polyglycolic acids). In addition, the parietal lesion was resected and remodelled, replacing the internal cortex.

The patient had no postoperative complications and had a favourable evolution. The subsequent cosmetic result was optimal. The histological study of the parietal lesion was non-pathological. The patient was followed up clinically for only one year, due to moving home for family reasons, and there was no evidence of recurrence or discomfort in the region of the operation.