This retrospective review details the clinical findings of a large cohort of Japanese patients with intraocular lymphoma and finds that cytokine analysis of vitreous biopsy is a valuable tool for diagnosis.
The authors reviewed data from 217 patients with intraocular lymphoma diagnosed at 25 medical institutions in Japan. They analyzed results from analysis of vitreous samples, including cytology, cytokine measurements and the IgH gene rearrangement test.
The average age at onset was 63.4 years, with women outnumbering men (132 vs. 85 cases). During a mean observation period of 41.3 months, 69 patients developed lymphoma in one eye and 148 had bilateral involvement.
Intraocular lymphoma with involvement of the central nervous system (CNS) was most common, found in 60.8 percent of the patients, whereas intraocular lymphoma without involvement of other organs was found in 28.1 percent of patients. With respect to onset patterns, 82.5 percent of patients developed primary ocular lesions, whereas 16.1 percent developed primary CNS lesions preceding intraocular lymphoma.
Blurred vision and ataxia were the most common ocular and extra-ocular symptoms that prompted patients to seek medical examination. Vitreous opacification was the most common ocular finding.
The detection rates of malignant cytology, IL-10/IL-6 ratio greater than 1.0, and IgH gene rearrangements were 44.5, 91.7, and 80.6 percent, respectively. IL-10/IL- 6 ratio greater than 1.0 had the highest overall detection rate and was extremely high (≥ 90 percent) in patients with or without vitreous opacification.
The five-year survival rate was 61.1 percent. Although the high percentage of cases presenting without CNS involvement may have been an important factor accounting for this high survival rate, the authors also hypothesize that earlier diagnosis and treatment of primary intraocular lymphoma may help prevent CNS involvement. Also, the survival prognosis of intraocular lymphoma may be gradually improving due to improvements in diagnosis and therapeutic strategies.
The authors’ statistical analysis found that the interval between the onset of primary ocular lesions and subsequent onset of CNS lesions (21.7 months) was significantly longer than that between the onset of primary CNS lesions and subsequent onset of ocular lesions (12.5 months). This suggests that primary intraocular lymphoma tends to progress relatively slowly. Also that correct diagnosis may be delayed if the case is diagnosed as an intraocular inflammatory disorder of unknown etiology.
They conclude that cytokine analysis should be performed more frequently as a supplementary test to confirm a diagnosis of intraocular lymphoma.