Primary Cutaneous B-Cell Lymphoblastic Lymphoma Arising from a Long-Standing Lesion in a Child and Review of the Literature.

Precursor B-cell lymphoblastic lymphoma (B-LBL) is a rare entity and primary cutaneous B-LBL is an even more uncommon diagnosis that typically affects children. A 4-year-old boy presented with a persistent rash on his left cheek for almost 2 years and was found to have primary cutaneous B-LBL. We report this case to emphasize that B-LBL should be in the differential diagnosis for an otherwise unimpressive persistent lesion in the head and neck region and review all reported pediatric cases of primary cutaneous B-LBL without extracutaneous involvement.