A Reactive Peripheral Gamma-Delta T-cell Lymphoid Proliferation After a Tick Bite

Peripheral gamma-delta T-cell proliferations are encountered in reaction to certain infections and in primary malignancies. Identifying sources of benign reactions is key in avoiding unnecessary workup and surveillance of these aggressive malignancies. Borrelia infections have been implicated in a number of lymphoproliferative disorders, but rarely, if ever, in this setting. While gamma-delta T-cells are known to play a prominent role in the immune response to Borrelia infection, B-cell differentiation is encountered in the majority of Borrelia-associated proliferations. We present here a unique case of benign-appearing peripheral gamma-delta T-cell lymphoid proliferation in the setting of a tick-bite with subsequent erythema migrans-like skin findings.