Perineural spread of rhino-orbitocerebral mucormycosis caused by Apophysomyces elegans
A 25-year-old male presented with complaints of gradually increasing painless hard swelling in the right maxillary region and paresthesia on the right side of face along distribution of trigeminal nerve over a period of 1 month. Patient had undergone functional endoscopic sinus surgery 2 years ago. On physical examination, there was no ulceration or induration of overlying skin. Laboratory investigations including hemogram and blood glucose levels were normal, and human immunodeficiency virus (HIV) serology was negative.\nMagnetic resonance imaging (MRI) revealed soft-tissue intensity lesion in the right premaxillary region, which was isointense on T1-weighted imaging and hypointense on T2-weighted imaging. Contiguous extension of lesion was noted along infraorbital nerve with widened infraorbital foramen, along the floor of orbit [], via the inferior orbital fissure into the pterygo-palatine fossa, through the foramen rotundum into the middle cranial fossa causing widening of foramen rotundum. In the middle cranial fossa, the lesion was limited to extradural space adjacent to cavernous sinus and Meckel's cave, with extension along the trigeminal nerve up to prepontine segment of trigeminal nerve []. Osseous destruction of the anterior wall of right maxillary sinus was seen with minimal mucosal thickening within. On contrast administration, the lesion showed homogenous enhancement [].\nOn imaging, among the differentials of fungal infection, lymphoma, and malignant lesions, fungal infection was favored. Biopsy was performed from premaxillary swelling, and fungal smear, cytology, and fungal culture were done. Histopathologic examination revealed granulomatous inflammation with giant cells. Giant cells showed intracytoplasmic nonseptate fungal hyphae which are highlighted by Grocott's methenamine silver (GMS) stain []. Fungal culture on water agar plate revealed sporangiophores which were long, unbranched, grayish brown, and with funnel-shaped apophyses. This morphology was indicative of A. elegans.\nSurgical debridement of the maxillary component was performed and systemic amphotericin B was administered. Follow-up MRI after 2 months revealed significant reduction of the lesion [].