Cribriform - Predominant Adenoid Cystic Carcinoma of the Naso ethmoidal – Orbital Region With Skull - Base and Intracranial Extension: A Rare and Challenging Presentation

Background: Adenoid cystic carcinoma (ACC) affecting the sinonasal and orbitofacial compartments is rare and usually diagnosed at an advanced stage because of nonspecific early symptoms.ACC is classically neurotropic, with perineural invasion (PNI) being a major adverse prognostic factor.We report a rare presentation of a massive cribriform-predominant ACC of the right naso-ethmoido-orbital region with skullbase and intracranial extension but without histologic perineural or vascular invasion.Case presentation: a 27-year-old man from Senegal and builder by occupation, developed a progressive right palpebral swelling in 2015 and underwent an undocumented exenteration in 2017.Recurrence manifested as painful right orbital swelling with bilateral nasal obstruction and anosmia.An endonasal biopsy in August 2024 confirmed ACC.He was referred to our center in Rabat in January 2025.Clinical exam revealed a 9-cm right fronto-orbital mass with purulent discharge and a right nasal cavity occluded by an ulcerated polypoid tumor.MRI showed a 103 × 111 × 91mm heterogeneous mass filling the ethmoid/maxillary/frontal complex with bone lysis, pachymeningeal enhancement, orbital obliteration, cavernous sinus and cavernous ICA involvement, and extension to the nasopharynx.He underwent subtotal excision with skullbase repair (multilayer fat graft + bio glue) and packing; directed healing followed by skin grafting.Final pathology: cribriform-predominant ACC, greatest axis ≈10 cm, no perineural invasion, no vascular emboli.Adjuvant concurrent radio chemotherapy was delivered.Conclusion: This case illustrates the biological heterogeneity of ACC: exceptional tumor bulk and multi-compartment invasion can coexist with absence of PNI.Multidisciplinary management combining maximal safe resection, skull-base repair and adjuvant radiotherapy/ chemoradiotherapy is essential.Long-term surveillance is mandatory given ACC's propensity for late local recurrence and distant metastases.Molecular profiling may further refine prognosis and guide future targeted therapies.