A 93-year-old male patient with suspected CTCL presented at our department. He had complained of generalized and recurrent eczematous lesions for 3 years and had been treated with intermittent topical steroids. The first histologic evaluation in January 2008 showed features compatible with small-plaque parapsoriasis. Psoralen–UV-A (PUVA) therapy had no effect. Five months later, the eruption had spread to more than 80% of the body surface and had become partially infiltrated. Findings from a new biopsy specimen revealed a subepidermal infiltrate composed of atypical small lymphocytes with a clinically significant degree of epidermotropism but no genuine abscess formation. The infiltrate consisted mainly of CD3+ T lymphocytes (with a CD4 to CD8 ratio of 1:2), and a clonal rearrangement for the γ-chain of TCR (TCR-γ) was observed. Findings from a screening for lymph nodes or visceral and bone marrow involvement were negative. No circulating Sézary cells could be detected, but the same clonal rearrangement of the TCR-γ was observed in the blood. The patient was considered to have stage IIIA CTCL (stage T4N0M0B0b according to the 2007 European Organisation for Research and Treatment of Cancer /International Society for Cutaneous Lymphoma criteria). In addition, he had complained of nail alterations over a 1-year period, which involved 9 of the 10 fingernails (Figure 1). Careful examination revealed anonychia (fingernail 2, right and left), onychomadesis (fingernails 1, 3, and 4, right; and fingernails 3 and 5, left), subungual distal hyperkeratosis (fingernail 1, left) and onycholysis (fingernail 5, right). Neither paronychium nor perionychium alterations were observed. There was also no discoloration or growth arrest, and the fourth left digit was normal. The patient denied any intake of systemic drugs, especially no cyclins. Histopathologic examination of a longitudinal nail biopsy (fingernail 1, left), involving the proximal nail matrix, revealed a horizontal bandlike lymphocytic infiltrate localized in the dermis of the nail bed and at the junction with the hyponychium. The atypical lymphocytes showed clinically significant epidermotropism with Pautrier microabscesses formation. No relevant modification of the proximal matrix was observed. The nail plate was proximally thin and became steadily substituted by hyperkeratosis distally (Figure 2). Periodic acid–Schiff (PAS) stains were negative for fungi. Immunostaining revealed a CD3+ lymphocytic infiltrate within the distal matrix, the nail bed, and the hyponychium. CD4 stained only one-third of the cells, whereas CD8 showed marked staining of the majority. The TCR-γ rearrangement showed identical clones in blood as well as in skin and nail materials (Figure 3).