Isolated frontosphenoidal suture synostoses: report of two cases and literature review

Anterior plagiocephaly is most commonly attributed to unilateral coronal synostosis. However, isolated premature fusion of the frontosphenoidal suture (FSC) represents a rare and often misdiagnosed cause due to its overlapping clinical presentation. Accurate diagnosis is essential, as treatment strategies and prognoses differ significantly.

To present a comprehensive literature review of FSC and to report two novel clinical cases-one managed with open fronto-orbital advancement and the other with endoscopic suturectomy.

A systematic review of reported FSC cases was performed and supplemented by two patients treated at our institution. Diagnosis was established using cranial computed tomography (CT) with three-dimensional (3D) reconstruction. The first patient underwent open fronto-orbital advancement, while the second was treated with early endoscopic suturectomy.

In both patients, isolated fusion of the frontosphenoidal suture was confirmed with preservation of the coronal sutures. The first patient, diagnosed at 9 months of age, presented with typical signs of anterior plagiocephaly without the Harlequin sign, and underwent open surgery with excellent postoperative craniofacial symmetry. The second patient, diagnosed earlier due to subtle craniofacial asymmetry, was treated endoscopically with favorable aesthetic results and no postoperative complications.

FSC represents a rare and underrecognized cause of anterior plagiocephaly. High clinical suspicion is required in cases of atypical cranial asymmetry with open coronal sutures. Cranial CT with 3D reconstruction is essential for accurate diagnosis and identification of the suture involvement. Both open and endoscopic surgical approaches can achieve satisfactory outcomes when appropriately indicated.