RESUMEN
BACKGROUND: Cutaneous T-cell lymphoma can be associated with clinically significant nail alterations, the presentation of which can be protean and misleading. To date, only a few reports have demonstrated direct specific tumor infiltration of the nail bed, while little is known about the efficacy of topical treatments. OBSERVATIONS: We describe the case of a 93-year-old man presenting with Sézary syndrome who developed clinically significant nail alterations. Light microscopy studies and T-cell receptor rearrangement analysis demonstrated the presence of a specific lymphocytic infiltrate within the nail bed. The patient was given repeated courses of topical mechlorethamine, leading to a sustained complete remission of both skin and nail alterations. CONCLUSIONS: Specific nail involvement should be recognized and considered in all patients with cutaneous T-cell lymphomas. Topical mechlorethamine remains an attractive therapeutic option in cases of specific nail alterations, especially for situations in which systemic therapies are either not indicated or unlikely to be well tolerated.