THORACIC NEUROBLASTOMA

Neuroblastomas are embryonal tumors of migrating neuroectodermal cells derived from the neural crest and destined for the adrenal medulla and sympathetic nervous system.
Neuroblastoma is used as a general term for all types of neuroblastic tumors.

· Neuroblastoma - (Schwannian stroma-poor)

· Ganglioneuroblastoma - intermixed (Schwannian stroma-rich)

· Ganglioneuroma - (Schwannian stroma-dominant)

· Ganglioneuroblastoma, nodular (composite, Schwannian stroma-rich/stroma-dominant and stroma-poor.

CLASSIFICATION OF NEUROBLASTOMA

1. Adrenal medulla (50%).

2. Extra-adrenal (sympathetic chain or ganglion).

• below the diaphragm (30%).
• in pelvic or visceral ganglia, paraganglia, or the organ of Zukerkandel.
• above the diaphragm (15-20%).
• in cervical or thoracic sites.
• 70-80% have involved regional lymph nodes or metastases at more distant sites at presentation.
• tumor may regress or mature spontaneously (in 5-10% of cases).
• about 20% of tumors are the result of a germinal mutation.
• a subset have an autosomal dominant pattern of inheritance.

ETIOLOGY

The etiology of neuroblastoma is unknown, but it appears unlikely that environmental exposure plays a major role. There have been a few reports of neuroblastoma associated with the fetal hydantoin, phenobarbitol or alcohol syndromes, suggesting that prenatal exposure to these substances may increase the risk of neuroblastoma. There have also been studies suggesting a weak association between neuroblastoma and paternal occupational exposure to electromagnetic fields, or maternal use of hair coloring products, but none of these associations has been confirmed. Moreover, no prenatal or postnatal exposure to drugs, chemicals or radiation has been either strongly or consistently associated with an increased incidence of neuroblastoma.

Although most of neuroblastomas appear sporadic, there has been a number of reports of familial neuroblastoma, as well as bilateral of multifocal disease, consistent with hereditary predisposition.

Constitutional chromosomal abnormalities have been described in lymphocytes of patients with neuroblastoma, although there is no apparent pattern. An interstitial deletion and a reciprocal translocation t(1;17) , both affecting 1p36, have been observed in patients with neuroblastoma. However, it is unclear if these 1p36 rearrangements contributed to neuroblastoma predisposition.

DIFFERENTIAL DIAGNOSIS

• Neuroblastoma
• Schwannoma
• Neurofibroma

REFERENCES

1. Berthold F, Sahin K, Hero B et.al. The current contributionof molecular factors to risk estimation in neuroblastoma patients. Europ J Cancer 1997;33: 2092-2097.
2. Brodeur GM, Pritchard J, Berthold F et.al. Revisions of the international criteria for neuroblastoma diagnosis, staging and response to treatment. J Clin Oncol 1993;17:1466-1477.
3. Schwab M, Shimada H, Joshi V, Brodeur, G. Neuroblastic tumours of adrenal gland and sympathetic nervous system. In: Kleihues P, Cavenee WK (eds) Pathology and genetics of tumours of the nervous system. International Agency for Cancer Research, IARC;1999.
4. Shimada H, Ambros IM, Dehner Lpet.al. Terminology and morphologic criteria of neuroblastic tumors: Recommendations by the International Neuroblastoma Pathology Committee. Cancer 1999;86:349-363.