Choroidal metastatic mucinous abscess caused by Pseudomonas aeruginosa: A case report

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) is considered a common pathogenic bacterium. Choroidal metastatic mucinous abscess caused by P. aeruginosa is rarely reported. CASE SUMMARY: We describe the diagnostic and treatment processes of a case involving a complex choroidal space-occupying lesion. Our analyses of early clinical manifestations revealed a high possibility of choroidal melanoma, as indicated by the choroidal space-occupying lesion and uveitis. Further magnetic resonance imaging results revealed no positive evidence for the diagnosis of choroidal melanoma. The exact properties of the space-occupying lesion could not be ascertained prior to surgery. However, the lesion was subsequently confirmed as a metastatic abscess by diagnostic vitrectomy. The occupying lesion was found to occupy 75% of the vitreous cavity in the surgery. The entire white viscous tissue was completely removed, and the necrotic retina was cleaned up. After surgery, microbiological culture revealed mucoid P. aeruginosa, which was sensitive to a variety of antibiotics. The bacterial infection grew and disseminated towards the outside of the eye. After the fifth injection, the left eye was successfully retained. CONCLUSION: This is a peculiar case because a huge, local, space-occupying lesion had formed due to the dissemination of low-toxic mucinous P. aeruginosa in the blood from the lungs to the choroid. After surgical removal, the bacteria were able to re-grow; thus, local infection re-spread following surgery. The patient lost vision, but we managed to retain the full structure of the eyeball and eliminated the focus of infection.