Ganglioneuromas in the Adrenal Medulla of F344 Rats

Abstract

Abstract. Of 60,048 aging F344 rats, 28 had ganglioneuromas of the adrenal gland. The rats were between 58 and 122 weeks old; 25 of them between 93 and 122 weeks when the tumors were found. The neoplasms were composed of large or small typical ganglion cells with a large pale nucleus and a prominent, often eccentric, nucleolus. The ganglion cells usually were distributed throughout the medullary tumor and surrounded by various numbers of supporting cells, including Schwann's cell types, and capsular or satellite cells. Often there was no clear-cut border between ganglion cells and neoplastic pheochromocytes. Electron microscopy of re-embedded tissues showed neurosecretory granules and cytoplasmic areas with an extensive rough endoplasmic reticulum (Nissl substance) in the ganglion cells and axons. The Schwann's cells were surrounded by a basement membrane and formed long cytoplasmic extensions around the axons. Almost all ganglioneuromas were associated with neoplastic pheochromocytes which usually were located at the edge of the tumors.Tumors of neurogenic origin (neuroblastoma, ganglioneuroblastoma, ganglioneuroma) are the most common solid abdominal neoplasms found in children [1,2,5,12,16,22,23]. Forty percent of them arise in the adrenal medulla [6]. We do not presently have a model system for studying the pathogenesis of these tumors in animals. None of the known cancer-inducing agents has produced a significant number of tumors of this type in the abdominal cavity of experimental animals, nor do they often occur spontaneously in untreated animals [7][8][9][10]19,20].Histological data on more than 60,000 F344 rats had accumulated from past bioassays. From these, we reviewed the morphology of 28 ganglioneuromas diagnosed histologically from adrenal gland tumors of F344 rats. The tumor samples were retrieved from the bioassay experiments conducted in the NCI Carcinogenesis Testing Program from 1972 to 1979 [13], and included material from chemically treated and untreated (control) rats. Materials and MethodsThe rats had been obtained when 6 weeks old from commercial suppliers and studied for 2 years [9]. Necropsies were done on all animals found dead and on those that were moribund 614

Endocrine Glands

“…238 Mixed forms pheochomocytoma and ganglioneuromas are also occasionally seen, suggesting a common histogenesis. 238 Mixed forms pheochomocytoma and ganglioneuromas are also occasionally seen, suggesting a common histogenesis.…”

A Spontaneous Ganglioneuroma in the Adrenal Medulla of a Young Wistar Hannover Rat

“…This was thought to be an extremely rare case, especially because of the young age of this animal, considering the very low spontaneous occurrence of ganglioneuroma in older rats such as those in two-year carcinogenicity studies (Haseman et al 1998;Pace et al 2002;Reznik et al 1980).…”

Activation of primary sensory neurons by the topical application of capsaicin on the epidermis of a re‐innervated organotypic human skin model

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