Ectopic low-grade adrenocortical carcinoma in the spinal region: immunohistochemical and molecular cytogenetic study of a pediatric case.

Ectopic adrenocortical neoplasms arising in the nervous system are very rare. We encountered an intradural, extramedullary case of an adrenocortical neoplasm of indeterminate malignant potential affecting a spinal nerve root in the distal lumbar region of a 5-month-old girl. The lesion recurred 6 months after the initial gross total resection. The tumor in both resections had increased mitotic activity (5/10 high power fields) and MIB-1 labeling indices of 23% and 33% at initial resection and recurrence, respectively. Both tumors demonstrated gains of chromosomes 5 and 12 by interphase cytogenetics, whereas insulin growth factor 2 was identified in the recurrent tumor by immunohistochemistry. This report demonstrates that ectopic adrenocortical tumors in the nervous system may exhibit clinicopathologic and cytogenetic features suggestive of adrenocortical carcinoma.