DIFFERENTIATING NEUROBLASTOMA OF PITUITARY-GLAND - NEUROBLASTIC TRANSFORMATION OF EPITHELIAL ADENOMA CELLS - CASE-REPORT

The authors report the case of a 40-year-old woman with a 12-year hist ory of irregular menses, amenorrhea, infertility, galactorrhea, a slig htly elevated prolactin level, and a slowly growing pituitary adenoma. She developed recent onset of visual symptoms, prompting craniotomy f or removal of an intrasellar tumor. Following surgery, her vision and prolactin levels returned to normal. Light microscopic and immunohisto chemical examination of the turner revealed it to be a neuroblastoma, which was immunohistochemically positive for synaptophysin, S-100 prot ein, and oxytocin. The neoplasm contained prolactin-positive neuroblas tic and pituitary epithelial cells. No other pituitary hormones were f ound. Electron microscopy demonstrated two cell types: one with freque nt neuritic processes containing neurosecretory granules and showing s ynaptic specialization, and another one compatible with epithelial ade nohypophyseal cells. A few cells had ultrastructural features that wer e transitional between neuronal cells and granulated epithelial cells. Agranular folliculostellate cells were also identified. Immunoelectro n microscopy demonstrated prolactin granules in the cytoplasm of the e pithelial cells, in a few transitional cells, and in scattered neuriti c processes. Ultrastructural and immunohistochemical features of the t umor suggested a transformation of pituitary epithelium to neuroblasti c cells. Hyperprolactinemia and associated clinical symptoms may in pa rt be attributed to selective prolactin secretion by neoplastic cells that were differentiating into adenomatous pituitary cells and, to a l esser extent, to cells differentiating into a neuroblastic line. Compr ession of pituitary stalk might also have been a contributory factor t o the increased prolactin levels. Moreover, the oxytocin produced by t he neuroblastic cells was considered an additional stimulus for prolac tin secretion by neoplastic cells or by the normal pituitary.