A 51-Year-Old Patient Develops Scaly Plaque on the Right Foot

A 51-year-old man slowly developed a 15 cm × 8 cm erythematous, notably indurated, and variably scaly plaque located on the medial and dorsal aspect of the right foot. By the time he sought medical attention, this minimally pruritic lesion had been present about 2.5 years. The rest of the cutaneous examination was unremarkable. Ipsilateral inguinal adenopathy was not detected. Several skin biopsies showed a similar pattern, consisting of hyperkeratosis and acanthosis accompanied by an intraepidermal clonal infiltrate of CD8+ atypical lymphocytes with pleomorphic nuclei, and a dense upper dermal infiltrate composed of more benign-appearing lymphocytes.

This clinical and pathological picture is most consistent with what disease entity?