Neuroblastoma in monozygotic twins - a case of probable twin-to-twin metastasis

Concordance for neuroblastoma in monozygotic twins has been reported only r arely, and the cause of the shared pathology has not been established. We d escribe a case of infant monozygotic twins developing tumours that were mor phologically, clinically and molecularly indistinguishable, but with a dela y of 6 months between times of presentation. Both tumours were metastatic a nd had amplification of MYCN and deletion at 1p36. Twin 1, who developed ne uroblastoma first, had constitutional karyotype abnormalities in at least 5 % of peripheral blood mononuclear cells involving 1p and 3p, and a deletion of 1q44 in 21% of cells. Twin 2 had a normal constitutional karyotype and lacked rearrangement or deletion of these regions. We propose an acquired n euroblastoma predisposition specific for twin 1, and in utero metastatic sp read of tumour cells to twin 2 via the shared placental circulation. (C) 20 01 Cancer Research Campaign.