[Macrophage activation syndrome revealing subcutaneous T-cell lymphoma in a 16-year old adolescent]. / Syndrome d'activation macrophagique révélant un lymphome T sous-cutané chez un adolescent de 16 ans.

Macrophage activation syndrome (MAS) is a multisystemic disorder resulting from an over-activation of the immune system leading to a more or less diffuse macrophagic infiltration into the tussues. Clinical signs including fever, hepatosplenomegaly, adenopathy are associated with abnormal values in laboratory test results (bi or pancytopenia, hepatic cytolysis, elevated LDH levels, coagulopathy) and hemophagocytosis. In children, it can be primary or secondary to several disorders. We report the case of a 16-year old patient admitted to the Department of Pediatrics with febrile leukopenia associated with impaired general condition and circular erythematous lesions spread to the lower limbs. The diagnosis of macrophage activation syndrome was retained based on clinical signs, laboratory test results and cytological results. Skin biopsy of these lesions showed subcutaneous panniculitis-like T-cell lymphoma. The purpose of this study is to insists on the peculiarities of this clinical case given the rarity of this type of subcutaneous T-cell lymphoma, much more in this age group. We want to highlight the importance of suspecting subcutaneous T-cell lymphoma in patients with MAS associated with subcutaneous erythematous lesions because this could be life threatening.