(25) Pityriasis lichenoides developing into mycosis fungoides

Pityriasis lichenoides and its subtypes

Pityriasis lichenoides represents a unique group of inflammatory skin disorders that include pityriasis lichenoides et varioliformis acuta (PLEVA), febrile ulceronecrotic Mucha-Habermann disease (a subtype of PLEVA), and pityriasis lichenoides chronica. The history, epidemiology, clinical features, pathophysiology, and treatment of this group of conditions are reviewed in this manuscript.

Mycosis fungoides--type cutaneous T-cell lymphoma arising before 30 years of age. Immunophenotypic, immunogenotypic and clinicopathologic analysis of nine cases

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 large-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 beta-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.

Mycosis fungoides beginning in childhood and adolescence

Mycosis fungoides is a form of cutaneous T cell lymphoma usually occurring in mid to late adulthood. We report 12 patients with mycosis fungoides whose eruption began before age 20 years, including one patient with histologic documentation at 5 years of age. The onset of mycosis fungoides during the first two decades may be more common than is generally recognized and should be included in the differential diagnosis of chronic dermatoses in children and adolescents.