Esthesioneuroblastoma – delayed postoperative radiosurgery for recurrence at short-term

Skull Base Region	Olfactory Groove
Histopathology	Esthesioneuroblastoma
Prior Surgical Resection	Yes
Pertinent Laboratory Findings	N/A

Case description

The patient was a 49-year-old male who presented with nasal obstruction and underwent a nasal septal reduction at an outside institution. Postoperatively, he developed progressive hyposmia and left-sided eyelid edema with midface pain. Antibiotic therapy was started without resolution of symptoms, and magnetic resonance imaging (MRI) demonstrated an ethmoid mass eroding through the cribriform plate into the frontal lobe. Transnasal endoscopic biopsy confirmed a Kadish C, Hyams grade 3 esthesioneuroblastoma. The patient underwent a craniofacial resection with positive margins ( Figure 2.5.1 ), followed by external beam radiotherapy (68.4 Gy in 38 fractions) with cisplatin sensitization. Imaging at 6 months revealed recurrence at the margin of radiotherapy field in the bilateral frontal lobes ( Figure 2.5.2 ), for which he underwent stereotactic radiosurgery (SRS) (6 isocenters, 4.9 cm ³ ; 18-Gy margin; 45-Gy maximum dose) ( Figure 2.5.3 ).

Radiosurgery Machine	Gamma Knife – Model C
Radiosurgery Dose (Gy)	18, at 50% isodose line
Number of Fractions	1

Critical Structure	Dose Tolerance
Optic nerve/chiasm	10 Gy maximum point dose <0.2 cc >8 Gy
Cavernous carotid artery	Tolerant, no evidence of SRS-induced stenosis