What might be a reason for performing a bone marrow biopsy in an infant with a mass and elevated urinary metabolites?

Performing a bone marrow biopsy in an infant with a mass and elevated urinary metabolites is often indicative of a possible neuroblastoma because this type of cancer can arise from neural crest cells and is frequently associated with elevated levels of metabolites such as vanillylmandelic acid (VMA) and homovanillic acid (HVA) in the urine. A bone marrow biopsy can help determine the extent of the disease and whether it has metastasized, which is crucial for staging and treatment planning.

In cases of neuroblastoma, the biopsy can reveal the presence of malignant neuroblasts, confirming the diagnosis and informing on how aggressive the cancer might be. This is particularly important in pediatric cases where early detection and intervention can significantly impact outcomes.

Other options do not align with the typical diagnostic use of a bone marrow biopsy for the signs presented. Ruling out iron-deficiency anemia would usually involve peripheral blood tests rather than a biopsy. Confirming a diagnosis of leukemia would indicate the need for a biopsy, but it is not primarily linked to elevated urinary metabolites as seen in neuroblastoma cases. Lastly, assessing for vitamin deficiency is more appropriately conducted through other laboratory tests rather than a bone marrow biopsy, which is more invasive and not standard for that purpose