Cutaneous T-cell lymphomas may present with a clinical course that is incongruent with the associated histologic findings. Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma classically presents as an abrupt eruption of disseminated ulcerated annular plaques with aggressive behavior and a poor prognosis. Herein we describe a vulvar primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma with a locally aggressive clinical course that was strikingly responsive to radiation therapy. As aggressive therapy involving systemic chemotherapy is indicated for primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, appropriate clinico-pathologic correlation is crucial for preventing potentially excessive or insufficient therapeutic intervention. Our case also highlights the pivotal role of both radiation therapy and infection control in the management of aggressive cutaneous vulvar lymphomas.