Multicentric ganglioneuroma in a steer.

Ganglioneuroma and neuroblastoma are tumors of similar origin; the latter is a rapidly growing, undifferentiated malignant type which may mature and differentiate into the former, a well-differentiated and usually benign type. Though both are neuroectodermal tumors, ganglioneuromas are composed of medullated or non-medullated nerve fibers and distinct mature ganglion cells [ 151, and in man, are found especially along the paravertebral line in the thorax and abdomen [ 11. Ganglioneuroma is a rare tumor in both domestic [9] and laboratory [ 131 animals. Most reports have concerned the benign tumor in rats [5, 1 I , 141, hamsters experimentally exposed to ethylnitrosourea precursors [ 121, dogs [7, lo], pigs [lo], horses [8, 101 and man [ 10, 151. Ganglioneuromas in cattle and buffalo also have been reported [4, 6, 9, 101. In cattle, most tumors developed from abdominal sympathetic plexus or elsewhere in the autonomic nervous sytem [9]. One tumor in a ten-month-old Hereford steer was located over the first lumbar segment of the spinal cord [4], while ganglioneuromas in three buffalo were found on the bulbar conjunctiva [6]. Described here is a ganglioneuroma in an apparently normal five-year-old Brahman steer which had multiple lesions on serosal surfaces and one lesion in a sternal lymph node. Numerous pedunculated, pale, firm, discrete tumors varying in size from 1 to 12 cm in diameter were found at slaughter on the parietal pleura, peritoneum, greater omentum, and spleen (figs. 1 , 2). The tumors were more frequent in the abdomen than in the thorax. A similar nodular tumor was observed in one sternal lymph node (fig. 3 ) . No other lesions were reported. The adrenal glands were not submitted for detailed examination, thus the possibility of adrenal lesions cannot be excluded. Representative portions of all lesions were fixed in 10% buffered neutral formalin, embedded in parafin, sectioned at 6 Fm, and stained with hematoxylin and eosin (HE), cresyl violet, Alcian blue-methyl green pyronin [3], Luxol fast blue and Glee’s silver impregnation. Histologically, the tumor in all locations consisted of Schwann’s cell cords which stained poorly with Luxol fast blue and formed interlacing fascicles resembling a neurofibroma. In