Clinical Presentation

The majority of low-risk neuroblastomas are discovered incidentally. An asymptomatic abdominal neu-roblastoma may be palpated during a routine physical examination or revealed in utero by prenatal ul-trasonography. A posterior mediastinal neuroblas-toma may be serendipitously seen on a chest film performed in a child with suspected pneumonia. Low-risk neuroblastomas may also cause signs and symptoms that prompt medical investigations. Relatively common direct mass effects in low-risk cases include progressive abdominal distention, cervical adenopa-thy, Horner's syndrome, and acute paraplegia. Systemic symptoms associated with low-risk cases include watery diarrhea from vasoactive intestinal pep-tide release by neuroblasts, tachycardia from excessive catecholamine production, and opsoclonus-my-oclonus-ataxia, which is thought to result from an autoimmune phenomenon mediated by antibodies cross-reacting with antigens on neuroblasts and on cells in the cerebellum (see Chap. 13).

In contrast to the marked preponderance of abdominal primaries in high-risk disease, up to 50% of stage-1 and stage-2 neuroblastomas are extraabdominal. Adrenal primaries and liver lesions occur in 80-90% of stage-4S cases, while morphologic evidence of bone marrow involvement is seen in ~35% of cases and subcutaneous nodules are present in 15% of cases (DuBois et al. 1999).

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