Case Report: Atypical Fungal Endophthalmitis Caused by Thyridium hongkongensis

Introduction: Herein, we report a case of endophthalmitis caused by the dematiaceous fungal species Thyridium hongkongensis. Case presentation: A 52-year-old male presented with pain and vision loss in his left eye visited our institution. Initial examination revealed decreased visual acuity and signs of intraocular inflammation consistent with endophthalmitis. Treatment with intravitreal antibiotics and vitrectomy was subsequently initiated. However, worsening of symptoms was observed 1 month after initiation of treatment. Subsequent vitreous culture revealed that the causative pathogen was Thyridium hongkongensis (previously Phialemoniopsis hongkongensis). A diagnosis of fungal endophthalmitis with rhegmatogenous retinal detachment was consequently established. Comprehensive management, including systemic and intravitreal antifungal therapy along with vitrectomy, was subsequently initiated. Although intraocular inflammation subsided postoperatively, the retina remained detached, and the patient’s final visual acuity was poor. Conclusion: This case highlights the diagnostic and therapeutic challenges associated with fungal endophthalmitis caused by Thyridium hongkongensis. Early recognition and aggressive treatment are crucial; however, visual prognosis remains poor, particularly in cases complicated by marked intraocular inflammation and retinal detachment.