Darier sign in a teenager with primary cutaneous marginal zone lymphoma.

Primary cutaneous marginal zone lymphoma (PCMZL) is a low-grade B-cell lymphoma that arises in the skin. An adolescent male presented with dermal nodules on the arms, legs, and back with a positive Darier sign, ultimately diagnosed as PCMZL. The nodules demonstrated a partial response to doxycycline in the setting of prior Lyme disease followed by a complete response to rituximab.