Paraneoplastic manifestations in children.

Paraneoplastic manifestations are signs and symptoms observed in patients with cancer, distant from the tumour or its metastases and not caused by invasion, obstruction or bulk mass. In children with cancer, paraneoplastic manifestations are rare and distinct from those observed in adults. Knowledge about paraneoplastic manifestations can be of great clinical importance because they may be the presenting sign of a tumour or its recurrence and hence facilitate early diagnosis. In contrast, they sometimes mask the symptoms of a tumour and cause diagnostic delay. In this review, paraneoplastic manifestations in children are described, including hypercalcaemia, Cushing syndrome, precocious puberty, opsoclonus/myoclonus, acquired von Willebrand disease, watery diarrhoea syndrome, and hypertension. The mechanisms causing these manifestations are also discussed.