[Subcutaneous nodules as a sign of malignant lymphoproliferative syndrome]

Skin involvement in children with malignant processes usually appears at the same time or after the diagnosis of the primary tumour. We present the case of a girl with cutaneous involvement prior to the diagnosis of a malignant lymphoproliferative process. A previously healthy 5-month old girl who presented with an inflammatory subcutaneous lesion on the right foot. During hospital admission due to bronchiolitis at 7 months with associated pancytopenia while the myelogram showed myeloid and megakaryocytic hypoplasia, the abdominal and foot ultrasound were normal. After completing corticoid therapy for her respiratory process and transfusional support, the foot lesion had disappeared at discharge. Two months later she had a local recurrence with associated scattered subcutaneous nodules. The skin biopsy confirmed malignant infiltration; the myelogram showed 6% blast infiltration, and both abdominal ultrasound and CT scan demonstrated lymph node involvement. Immunophenotype confirmed the diagnosis of Precursor B Cell Lymphoblastic Leukemia-Lymphoma. Although complete remission was achieved at the end of the induction chemotherapy according Euro-LB-02 protocol for stage IV, the patient presented a refractory leukaemia relapse thirteen months after diagnosis.

Malignancy should be suspected in the presence of a skin lesion with torpid evolution and biopsy should be considered. Differential diagnosis of malignant skin lesions in children, especially in infants, must include mainly secondary involvement of leukaemia, lymphoma, metastases of neuroblastoma or rhabdomyosarcoma and less frequently other primary processes. In our patient with an isolated cutaneous presentation, the progression of her malignant lymphoproliferative process could be modified by the corticotherapy given before the definitive diagnosis.