Gaucher or pseudo-Gaucher? The challenge of several diseases colliding in a pediatric patient.

We present here an unusual case in which 3 distinct, apparently unrelated clinical entities were diagnosed in a pediatric patient. A 6-year-old female, previously diagnosed with neurofibromatosis type 1, presented with a mediastinal T-cell lymphoblastic lymphoma; the metabolic and molecular confirmation of Gaucher disease were obtained after typical Gaucher cells were found in the patient's bone marrow after a staging biopsy. The morphological and ultrastructural findings leading to the incidental diagnosis of this rare metabolic disorder are illustrated. In addition, we discuss the possible pathogenetic relationships among these 3 distinct clinical entities, as well as the challenges in the differential diagnosis of bone marrow histiocytic infiltrations in patients with hematologic malignancies.