Neonatal macrocephaly: cerebral PNET (Primitive Neuro Ectodermal Tumor) or neuroblastoma as an infrequent cause: a case report and a review of the literature

Case presentation: We report a male term newborn with a congenital macrocephaly, 3.5 standard deviation above median noted at birth. The antenatal history, including ultrasonography was reported to be normal. The head circumference was measured between 10th and 50th percentile at 21 weeks 3/ 7 and 30 weeks 5/ 7, respectively. Postnatal adaptation was complicated by poor respiratory effort and the baby had to be intubated at 8 minutes of age.

On clinical examination at admission to our unit we noted: A wide and tense anterior fontanel, splayed sutures without external bruising or swelling, a normal inspection of the spine and a provocable gag reflex, bilaterally 3mm wide and isoreactive pupils and general hypotonia with all extremities spontaneously and symmetrically moved were described.

Initial imaging investigation was performed with a head ultrasound. There was a large intra- parenchymal mass in the right cerebral hemisphere with a compressed right lateral ventricle and a massively dilated right lateral temporal horn, as well as an enlarged and laterally displaced right frontal horn. All ventricles showed signs of ventriculitis. These findings were investigated further with a CT scan and a MRI. The initial differential diagnosis included teratoma and neuroblastoma with a communicating hydrocephaly. A decompression had to be performed and the histology showed the findings of a Primitive Neuro Ectodermal Tumor (PNET) or neuroblastoma. The cytogenetic analysis showed a previously reported abnormal clone with structural rearrangement involving chromosomes 1 and 15 and tetraploidy with unstable number of chromosomes (ISCN Nomenclature: 92, XXYY,? t (1;15) (p36; q24)/ 46, XY/ 92, XXYY), a mutation previously described.

Discussion and review of the literature: The reported incidence of neonatal brain tumors is between 1.4 and 3.6 per 100,000 live births. The most commonly reported findings in a review of 250 cases of previously published congenital brain tumors were macrocephaly (28.7%), hydrocephalus (17.3%), detection by imaging pre- or postnatally (12.2%) and stillbirth (10.4%). Classically reported signs of intracranial hypertension reported in older children are very rarely present. In a previous review of 230 cases, 23 patients had an associated dysmorphic feature of various and nonspecific type.

Conclusion: Congenital macrocephaly should be investigated carefully. The most frequent pathologies found, include hydrocephaly and intra- or extracranial hemorrhage. An initial head ultrasound seems to be adequate as a screening method. Should there remain some uncertainty after a CT scan, better imaging results are obtained with a MRI and when a tumour is found, the definite diagnosis will be secured by histopathology.

Key words: macrocephaly, hydrocephalus, neuroblastoma, PNET