Pheochromocytoma--pathohistologic and immunohistochemical aspects

Pheochromocytoma originates in chromaffin cells of the adrenal medulla. Its incidence is similar in both sexes and most frequent between the ages of thirty and fifty. Multiple and bilateral pheochromocytomas constitute 5 to 10 percent of all cases. Pheochromocytoma occurs sporadically or is related to family syndromes such as: syndrome of multiple endocrine neoplasia--MEN IIA and IIB, neurofibromatosis (von Recklinghausen's disease), von Hippel-Lindau's disease, Sturge-Weber's syndrome, and tuberous sclerosis. Cases in a family usually occur at a younger age and are mostly bilateral and with more aggressive biological behaviour. The aim of the study was to make histomorphological and immunohistochemical analyses of 52 pheochromocytomas. These cases are the surgical material from the Centre of Endocrine Surgery, Institute of Endocrinology, Diabetes, and Metabolic Disorders, Clinical Centre of Serbia, Belgrade, over the period from 1974 to 1997. Frozen and fixed sections, which were cut from paraffinembedded material and stained by both hematoxylin-eosin and PAS, were used in order to make pathohistological diagnoses. The expression of chromogranin A, S-100 protein and ACTH was examined using the PAP method, while neuronspecific enolase (NSE), synaptophysin and neurofilament were examined by the APAAP method with appropriate antibodies (DAKO). The patients were between 4 and 65 years of age (average age 38.5) and there were 28 females (63.64%) and 16 males (36.36%). The largest pheochromocytoma had the diameter of 12 cm, and weight of pheochromocytomas in question was from 13.5 to 370 grams, the average weight being 83.4 grams. On gross examination, the tumours proved to be well-defined, either by fibrous capsule, or by adrenocortical tissue. The cross-sections of tumours were mainly of pale red-grayish colour, and showed numerous foci of necrosis, haemorrhage and cystic softening. Histological appearance of pheochromocytomas was with significant irregularities in shapes and dimensions of the cells and their patterns. Pheochromocytes were mostly of polygonal shape (45 cases, 86.54%), whereas in 7 cases (13.46%) fusiform cells were evident. Cells were arranged, either in trabeculae intermingled with thin-walled sinusoids, or in small alveolae circumferenced by fibrovascular stroma. PAS positive hyaline globules were often present in the cell cytoplasm and also extracellularly. Cellular and nuclear pleomorphism, binuclear and multinuclear cells, as well as gia