Synchronous Primary Central Nervous System and Pulmonary Lymphoma in a 7-Year-Old Female with Unspecified T-Cell Immunodeficiency.

Primary central nervous system lymphoma (PCNSL) is rare in children with immunocompromise as an important risk factor. A 7-year-old girl with unspecified T-cell immunodeficiency presented with left-sided weakness and was found to have a right-sided frontal lobe mass on imaging. The mass was resected; histopathology and molecular studies evidenced diffuse large B-cell lymphoma. Prior chest imaging had revealed left upper lobe mass, and repeat chest imaging revealed multiple pulmonary nodules, initially concerning for metastasis. Video-assisted thoracoscopic surgical wedge resection of the lung mass was performed; the molecular profile was distinct from the PCNSL, suggesting synchronous de novo lymphomagenesis of brain and pulmonary primaries.