1 Case Presentation
A 40-year-old male patient presented with a 5-month history of persistent right facial numbness and odontalgia. Histopathology confirmed chronic invasive fungal sinusitis (CIFS) complicated by extensive skull base osteomyelitis and ipsilateral internal carotid artery (ICA) stenosis. His comorbidities included poorly controlled type 2 diabetes mellitus, chronic renal insufficiency, and previous corticosteroid exposure. The patient received comprehensive endoscopic skull base debridement combined with long-term oral antifungal therapy and perioperative antibacterial agents, achieving satisfactory clinical recovery.
2 Surgical Procedure
The patient underwent endoscopic skull base surgery under general anesthesia, with an operative duration of 180 min and an estimated intraoperative blood loss of 150 mL. The core surgical goal was radical debridement of invasive fungal lesions while preserving vital anatomical structures, including the right ICA, cranial nerves, dura mater and orbital contents.
Surgical access was established via the right nasal cavity using 0° and 70° rigid endoscopes. Combined procedures included endoscopic skull base lesion resection, clival debridement, right trans-Caldwell-Luc maxillary lesion resection, complete endoscopic ethmo-sphenoid maxillary sinusotomy, and right medial orbital decompression. The surgical field exposed the right sphenoid sinus, pterygoid process, greater sphenoid wing, skull base and clivus, where widespread bony destruction was identified. Necrotic tissue extended deeply into the nasopharynx and parapharyngeal space.
All infected mucosa, devitalized soft tissue and sequestra were thoroughly debrided until healthy cortical bone was reached, with frozen section intraoperatively verifying complete removal of infected tissue. Doppler ultrasound precisely mapped the stenotic lacerum segment of the right ICA adjacent to lesions, which was fully protected throughout dissection. The exposed middle cranial fossa dura appeared mildly thickened but intact, with no cerebrospinal fluid (CSF) fistula identified. Medial wall decompression of the right orbit was performed to release soft tissue tension.
The right maxillary, ethmoid and sphenoid sinuses were widely marsupialized to maintain long-term drainage. After meticulous hemostasis, the surgical cavity was packed with hemostatic materials. No catastrophic vascular injury, CSF leak or neurological deficit occurred intraoperatively.
This surgery achieved gross total resection of soft tissue lesions within the right sphenoid sinus and controlled invasive disease of the skull base and pterygoid region, while fully preserving the ICA, cranial nerves, dura mater and orbital structures. Protection of these critical anatomical structures guaranteed operative safety and facilitated favorable early postoperative recovery.
Multimodal preoperative imaging (skull base CT and nasopharyngeal enhanced MRI) was fully documented to clarify surgical indications and the full invasive scope of lesions, providing anatomical evidence for personalized endoscopic skull base debridement planning.
Preoperative skull base CT revealed extensive irregular bone destruction involving the right sphenoid sinus, pterygoid process and greater wing of the sphenoid bone, accompanied by diffuse osteolytic lesions of bilateral upper alveolar processes and hard palate (Fig. 1a).
Complementary enhanced MRI further identified necrotic soft tissue lesions with restricted diffusion in the right sphenoid sinus, clivus and deep nasopharynx, which extended into the parapharyngeal space and induced mild thickening of the middle cranial fossa dura mater. Critically, the C3–C6 lacerum segment of the ipsilateral ICA adhered tightly to fungal lesions with mild luminal stenosis, posing a high risk of intraoperative vascular injury (Fig. 1b).
The bone and soft tissue invasion delineated on multimodal imaging directly guided surgical strategy: radical debridement of all infected mucosa, necrotic tissue and sequestra down to intact healthy cortical bone, concurrent orbital decompression to relieve orbital soft tissue compression, and real-time Doppler ultrasound localization for full protection of the stenotic ICA. All preoperative CT and MRI sequences (T1WI, T2WI, post-contrast series and diffusion-weighted imaging) are provided as supplementary figures to clearly demonstrate lesion distribution and surgical boundaries for readers.
The comprehensive overview of the diagnostic and therapeutic workflow for CIFS complicated by skull base osteomyelitis and internal carotid artery involvement, is shown in Supplementary Video 1.
Detailed postoperative serial imaging and clinical follow-up data are supplemented to objectively reflect therapeutic efficacy and safety:
Short-term postoperative imaging evaluation: 1-day postoperative MRI showed complete resection of soft tissue lesions in the right sphenoid sinus with stable residual inflammatory lesions at the sphenoid greater wing; no newly emergent skull base bone destruction, ICA rupture or intracranial hemorrhage was observed (Fig. 2).
At postoperative day-10, significant absorption of intraoperative packing materials and surgical cavity hemorrhage was confirmed, facial and eyelid soft tissue edema subsided obviously, bilateral sinus inflammation and right mastoid effusion were alleviated, and the stenosis of ICA remained stable without vascular wall injury (Fig. 3).
Postoperative complications: No major intraoperative or postoperative adverse events occurred, including massive vascular bleeding, cerebrospinal fluid (CSF) leakage, permanent cranial nerve dysfunction, intracranial infection or visual deterioration. The patient experienced only transient mild facial soft tissue swelling, which resolved within 10 days after surgery.
Improvement of clinical symptoms: The chief complaints of persistent right facial numbness and odontalgia were markedly relieved one week postoperatively. At discharge, nasal endoscopy showed no purulent discharge or recurrent fungal lesions; hypoesthesia distributed in the infraorbital and mental nerve territories was significantly ameliorated, without recurrent nasal itching or sneezing.
Postoperative histopathological examination serves as the gold standard to confirm invasive fungal infection, and combined special staining results are supplemented in detail. Specimens harvested from the right pterygoid process and skull base osteolytic lesions underwent routine HE staining, periodic-acid-schiff (PAS) and Gomori-methenamine-silver (GMS) fungal special staining. Microscopic observation revealed severe inflammatory infiltration, focal tissue necrosis, sequestrum formation, and massive septate fungal hyphae and spores with positive PAS and GMS staining, which pathologically verified the diagnosis of chronic invasive fungal sinusitis complicated with skull base osteomyelitis. Fungal elements were not detected in maxillary and sphenoid sinus mucosal samples, which indicated focal invasive growth of fungi limited to skull base bony structures rather than diffuse sinus mucosal involvement.
Standardized long-term antifungal therapy was administered postoperatively based on pathological confirmation of invasive fungal infection: oral voriconazole 200 mg twice daily as maintenance antifungal treatment, with a total treatment course of six consecutive months. Perioperative broad-spectrum intravenous antibiotics (piperacillin-sulbactam combined with levofloxacin) were used for 7 days to control secondary bacterial co-infection. Regular liver function monitoring every two weeks was arranged throughout the whole antifungal medication course to avoid voriconazole-induced hepatotoxicity.
3 Postoperative Pathological Confirmation of Fungal Infection
Postoperative histopathological examination represents the gold standard for diagnosing invasive fungal sinusitis, with detailed results of special staining provided herein. Specimens harvested from osteolytic lesions of the right pterygoid process and skull base underwent routine HE staining plus PAS and GMS fungal-specific staining. Microscopic analysis revealed severe inflammatory infiltration, focal tissue necrosis and sequestrum formation, alongside abundant septate fungal hyphae and spores with positive PAS and GMS staining. These findings pathologically confirmed CIFS accompanied by skull base osteomyelitis. Notably, no fungal elements were identified in mucosal specimens from the maxillary and sphenoid sinuses, indicating focal bony invasive growth of fungi rather than diffuse mucosal involvement of the paranasal sinuses.
4 Standardized Postoperative Antifungal Regimen
Based on pathological confirmation of invasive fungal infection, long-term targeted antifungal therapy was administered postoperatively. Oral voriconazole 200 mg twice daily was prescribed as maintenance antifungal treatment for a total continuous course of six months. Perioperative broad-spectrum intravenous antibiotics (piperacillin-sulbactam combined with levofloxacin) were administered for 7 days to control concomitant bacterial co-infection. Liver function tests were scheduled biweekly throughout the entire antifungal course to monitor voriconazole-related hepatotoxicity.
The Author(s). This article is published by Higher Education Press at journal.hep.com.cn.
This is an open access article distributed under the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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