Malignant Adrenal Tumors

Abstract

Malignant adrenal tumors are rare neoplasms of glandular tissue that have not been well studied largely due to their low incidence in the population. In the United States of America, adrenocortical carcinomas occur with an estimated annual frequency of two cases per million, while malignancies of chromaffin tissue, which constitutes the adrenal medulla and also exists at extra-adrenal paraganglionic sites, occur one-third to one-half as often [1]. These tumors are of particular interest because they are often functional. Adrenocortical carcinomas may cause hypercorticalism, hyperaldosteronism, adrenogenital syndrome, virilization, feminization, or precocious puberty; and malignant chromaffin tumors (malignant pheochromocytoma) may cause severe hypercortisolism as a manifestation of hypersecretory hormonal function. Treatment results and survival statistics in adrenal tumors are complicated by the lack of specific morphological characteristics or histologic criteria which correlate with malignant behavior. With the exception of anaplastic adrenocortical carcinoma, these tumors often appear extremely well differentiated (accounting for their hormone-producing function) and only in the presence of recurrence, local invasion, or dissemination can the malignancy of the tumor be confirmed. The overall 5-year survival rate for patients following resection of malignant tumors confined to the adrenal gland is approximately 40%. However, the presence of metastatic disease in the majority of patients means a much poorer prognosis with a life expectency of less than 3 years, although some individuals may survive long-term [1].