PREVALENCE OF MYD88 L265P MUTATION IN HISTOLOGICALLY PROVEN, DIFFUSE LARGE B-CELL VITREORETINAL LYMPHOMA

Myeloid differentiation primary response gene 88 (MYD88) is a universal adaptor protein in the innate immune system. When associated with a proline for leucine substitution mutation at position 265 (L265P), the protein becomes constitutively activated, amplifying the intracellular pro-inflammatory signal. Recently, we reported two cases of vitreoretinal lymphoma (VRL) that were positive for the mutation. The purpose of this study was to determine prevalence of the MYD88 L265P mutation in a larger series of VRL.

Retrospective chart review of 25 patients with histologically confirmed VRL evaluated at Mayo Clinic, Rochester, between January 2000 and March 2015. Paraffin-embedded blocks from the vitreous were submitted for polymerase chain reaction testing of the L265P mutation.

The mutation was positive in 82.4% of all VRL cases and 86.7% of primary VRL cases. The minimum necessary DNA concentration needed for the polymerase chain reaction assay was 4.93 ng/mL.

MYD88 gene analysis is a helpful ancillary tool for diagnosing VRL. It often requires fewer cells than flow cytometry or cytology and may be especially useful in early cases where a sufficient number of cells may not be available.