Peripheral T-cell lymphoma with eosinophilia presenting as monoarthritis: a case study.

Direct involvement of the joints is unusual in patients with non-Hodgkin's lymphoma (NHL). This may pose a diagnostic problem for pathologists, especially since synovial localization can disclose NHL. In the following case of T-cell NHL with eosinophilia, we point out the essential importance of clonality analysis on frozen tissue to distinguish between synovial NHL and specific inflammatory damage.