Histologic assessment of response to intraocular injection of amphotericin B in advanced rhino-sino-orbital mucormycosis

Objectives Rhino-sino-orbital mucormycosis (RSOM) is a life-threatening, emergent medical and surgical condition with high mortality. Although direct intraorbital delivery methods of amphotericin B have been explored, clear guidelines for its administration and dosing are lacking. We conducted this prospective study to determine the role of intraorbital amphotericin B (IOAB) in the management of advanced RSOM and assessed histologic changes in response to IOAB administration. Methods Patients with advanced orbital disease were offered treatment with IOAB before exenteration. Individuals who refused IOAB and underwent orbital exenteration made up a control group. Hematoxylin-eosin–stained slides of orbital exenterations were reviewed and representative whole slide images were captured. Areas of necrosis, inflammatory cell infiltrate, and fibrosis were annotated as indicators of tissue inflammatory response, quantified and estimated as a percentage of the total area of the tissue. A semiquantitative assessment of fungal load was conducted. Results The control group (n = 9) showed statistically significantly greater mean area (P = .004) and percentage area (P = .002) of tissue destruction, angioinvasion (P = .02), and optic nerve invasion (57% vs 33%; P = .31) compared with the intervention group (n = 9). Fungal load was low in test cases but high in most of the control group (P = .15). Inflammation of ocular structures was absent in 5 test cases but present in all control group cases (P = .008). Conclusions The considerably lower tissue destruction, fungal load, angioinvasion, and invasion of the optic nerve in orbital exenteration specimens following administration of IOAB indicates a promising role in the treatment of patients with RSOM and advanced involvement of the orbit.