A unique case of phaeohyphomycosis subretinal abscess in a patient with arthropathy and lung pathology
A 67-year-old male presented to the emergency eye centre (EEC) complaining of a painful right eye of 5-day duration. The medical history included active rheumatoid arthritis. His regular medications included sulfasalazine, prednisolone, and methotrexate for his rheumatoid disease.\nClinical examination revealed a visual acuity (VA) of 6/9 with minimal conjunctival injection, anterior chamber (AC) cells 1+ and posterior synechiae (PS). A diagnosis of anterior uveitis was made and the patient was commenced on topical prednisolone 1% and topical cyclopentolate 1%. The response to this treatment was good and the steroids were slowly tapered over 1 month; however, before cessation of treatment, the anterior segment inflammation worsened. The patient represented with VA 6/36 and AC cells 3+, extensive PS and a posterior vitritis. Immediate management included a subconjunctival injection of mydricaine No. 2, the topical treatment was increased and an urgent referral was made to the uveitis service.\nAt review, 4 weeks after presentation, the anterior and posterior segment inflammation remained and a white mass was noted in the peripheral nasal retina [ upper plate], almost at the ora serrata. A diagnosis of presumed Toxoplasma chorioretinitis was made and treatment with pyrimethamine and sulfadiazine followed by oral clindamycin was initiated. On further questioning, it was discovered that there was the possibility of a previous pulmonary tuberculosis (TB) infection. The patient's previous employment was gold-mining. A chest X-ray showed apical lung scarring on the right. He had had no previous treatment for active tuberculosis. In view of concern over possible reactivation of TB with an increase in oral steroids, further investigations were performed. HIV testing was negative. Quantiferon and induced sputum sampling were also performed (all negative) and the dose of prednisolone was increased to 60 mg daily. Blood cultures were also negative and there was no serological evidence of Toxoplasma infection (toxoplasma latex <16).\nThe patient responded to oral steroids and clindamycin, with a reduction in intraocular inflammation and improved VA of 6/18 after 2 weeks treatment. However, when the oral prednisolone was gradually reduced and the clindamycin stopped (after 5 weeks treatment), there was an increase in intraocular inflammation and VA reduced to 3/60. A diagnostic pars plana vitrectomy was therefore performed with vitreous sampling, which revealed a chronic vitritis without infectious agent or neoplasia. No herpes family viruses or toxoplasma organisms were identified on polymerase chain reaction testing.\nIn order to clinch the diagnosis, combined cataract surgery, retinal biopsy, and intraocular oil tamponade was performed. The combined procedure facilitated access to the anteriorly located subretinal mass. Surgery was performed 4 months after the patient initially presented with acute anterior uveitis. The nasal sub-retinal mass was biopsied using a 23-gauge (23G) vitrector hand piece and samples sent to histopathology and microbiology. Haematoxylin and eosin stained sections revealed an abscess with occasional granulomata. Close inspection showed brown pigmented septate branching hyphae that stained strongly with Masson Fontana melanin stain and with a Periodic Acid Schiff (PAS) and silver stain [ middle and lower plates]. The presence of a melanin containing, septate, branching, and mycelial fungus on histopathology was diagnostic of phaeohyphomycosis infection, on morphology alone. Prolonged fungal culture of the biopsy was negative and 18S ribosomal subunit polymerase chain reaction (PCR) was also negative (most likely due to the presence of PCR inhibitors in the sample). The absence of a culture and PCR result did not permit precise speciation of the phaeohyphomycosis fungus. The patient was referred to the infectious diseases department and oral voriconazole therapy initiated. The patient remained under joint care and was treated with antifungal therapy for 6 months; however, no primary source of fungal infection was identified. Following retinal biopsy the patient developed a retinal fold secondary to proliferative vitreoretinopathy (PVR), which extended from the biopsy site to the optic disc. Vitrectomy, removal of silicone oil, epiretinal membrane peel, subretinal PVR removal and retinectomy were performed with laser retinopexy and intraocular gas tamponade. Unfortunately, the patient required two further operations for rhegmatogenous retinal detachment. Currently, the retina is flat with heavy silicone oil tamponade and the VA is 2/60. Further retinal biopsy taken during vitrectomy for retinal detachment revealed no fungal elements on microscopy and intravitreal amphotericin B was also injected perioperatively.