The role and contribution of clonality studies in the diagnosis of lymphoproliferative disorders.

OBJECTIVES

To explore the frequency, context and diagnostic impact of B- and T-lymphocyte clonality assay use in the assessment of possible lymphoproliferative disorders at a central haematopathology diagnostics hub.

METHODS

All cases reported by haematopathologists over a sixteen-month period were identified, n = 4462, and those which had clonality studies undertaken analysed further.

RESULTS

Clonality studies were requested in 9% of cases, directly contributing to a diagnosis being made in 79%. They were most frequently used to help distinguish reactive lymphoid infiltrates from low-grade B-cell lymphomas and in cases of possible T-cell lymphoma, facilitating a diagnosis being made in over 90% of these. In contrast when clonality assays were requested as a diagnostic adjunct in cases with an atypical cutaneous lymphoid infiltrate, and in occasional cases of lymphoid proliferations with Hodgkin-like cells or EBV-driven proliferations, a definitive final diagnosis was possible in less than 60% of cases.

CONCLUSIONS

Clonality studies were used in 9% of cases assessed for a possible lymphoproliferative disorder and had a differing impact depending on the differential diagnoses being considered. These findings can be used to guide access to clonality assays by highlighting the likelihood of an informative result in different diagnostic settings.