Background: Cutaneous T-cell lymphomas (CTCLs) rarely arise before 30 years of age; therefore the characteristics of these lymphomas are largely unknown.

Objective: Our purpose was to assess the clinical and pathologic aspects of CTCL in young persons.

Methods: We identified nine patients who had epidermotropic CTCL by 30 years of age and analyzed their lymphoma phenotypes and genotypes.

Results: The diagnosis of CTCL was made an average of 6 years after the reported onset of the lesion. Histologic examination revealed the mycosis fungoides (MF) form of CTCL, and none of the patients underwent conversion to nonepidermotropic or iarge-cell variants of CTCL. The immunophenotypes were typical of MF-type CTCL; seven of eight lymphomas tested were predominantly CD4⁺ although in only three were abnormal CD4/CD8 ratios present. All four cases tested were CD7⁻ (Leu-9⁻), and seven of eight specimens tested exhibited deficient Leu-8 expression. The loss of one or more pan-T-cell markers was found in four of eight patients tested. Clonal β-chain T-cell receptor gene rearrangements occurred in skin samples from four of eight tested cases.

Conclusion: A persistent eruption, even in youths and young adults, should be thoroughly evaluated for possible CTCL.