[Morphological criteria of the malignancy of pheochromocytoma].

Morphological features of the chromaffin tissue tumours removed surgically were studied in detail. The complex of the histological and cytological signs characterizing morphological criteria of the pheochromocytoma malignancy is recommended to be used in the everyday diagnostic practice. It is suggested that pheochromocytomas should be divided into the three main variants which seem to be stages of the neoplastic process: so-called benign, borderline malignant, and malignant tumours. The latter may be metastasizing or without visible metastasis but having all the features of morphological malignancy identical to those in the metastasizing neoplasms. The group of the borderline malignant pheochromocytoma is of importance not only theoretically but practically as well, since it complements our concepts of the neoplastic process dynamics and in many cases may be the indication of the possible prognosis of the disease.