Lymphomatoid annular erythema: a new form of juvenile mycosis fungoides

Conflicts of interest: none declared. Sir, Mycosis fungoides (MF) may begin in childhood. Usually, juvenile forms of this T‐cell primary cutaneous lymphoma have clinical and histological features of the typical adult form. However, in children particularly, some clinical aspects may lead to an incorrect diagnosis. We report an unusual form of juvenile MF mimicking erythema annulare centrifugum (EAC). A 12‐year‐old girl presented with 'erythema annulare centrifugum' of 6 months' duration. The eruption began as ordinary erythematous papules localized on the trunk, hips and neck, without any scaling or vesiculation (Fig. 1). These asymptomatic lesions grew larger centrifugally with an advancing urticarial margin to form rings of about 10 cm in diameter. The centre of the rings was the colour of ordinary skin and discretely raised. In addition, two discrete hypopigmented patches could be seen on the back and the right arm. The lesions had no tendency towards spontaneous resolution. There was no evidence for familial EAC, nor arthropod bites. She had frequent migraines that were treated over a period of 8 months with dihydroergotamine, but the treatment was stopped 1 month before the appearance of the first lesions. No other medication was taken. There was no significant lymphadenopathy, nor hepatosplenomegaly, and her general condition was normal. Two biopsy specimens were taken from the edge of two rings and examined with direct immunofluorescence. Histological examination showed a proliferation of atypical lymphocytic cells in the upper dermis with epidermotropism and Pautrier microabscesses. Immunohistochemical staining revealed the prevalence of T lymphocytes with a predominance of CD4+ T cells (Fig. 2). Direct immunofluorescence was negative. Genotypic analysis of clonality by polymerase chain reaction (multiplex/denaturing gradient gel electrophoresis) revealed a monoclonal T‐cell rearrangement on both sites and a polyclonal profile on circulating lymphocytes. The diagnosis of cutaneous T‐cell lymphoma was confirmed. Laboratory studies revealed no abnormalities except a discrete CD8 lymphopenia (385 mm−3; normal 600–900); the search for Sézary cells was negative. Serology for viruses (Epstein–Barr, human T cell lymphotropic type 1, human immunodeficiency) and Lyme borreliosis was negative. Abdominal and pelvic computed tomographic scans and bone marrow biopsy specimen were normal. The final diagnosis was thus a stage IB MF. Treatment with topical chlormethine twice a week was started, which led to complete remission at the end of a 6‐month treatment. The treatment was then stopped, but a relapse took place, with histological confirmation 1 month later. The same local chemotherapy was reintroduced for another 6 months, with more modest efficacy this time. Psoralen plus ultraviolet A (PUVA) therapy was then carried out: 22 sessions of PUVA, i.e. 85 J in all, were administered which brought about a brief but complete remission. The patient is now 15 years old; topical chlormethine is still necessary twice a week to obtain clinical remission.