Pituitary adenoma-neuronal choristoma is a pituitary adenoma with ganglionic differentiation

Characteristics of ganglion cells in pituitary gangliocytomas

“…The precise relationship between this adenoma subtype and the more frequent occurrence of accompanying neuronal cells remains enigmatic, as appropriately stressed by Scheithauer et al 7 The possibility of a transdifferentiation from normal or adenomatous pituitary epithelial cells to neuronal cells is suggested by many authors. 7,9,12,14,[20][21][22] In particular, the presence of numerous cells with morphological features intermediate between pituitary adenoma and neurons was pointed out by Horvath et al 14 A support to the hypothesis of transdifferentiation is given by in vitro investigations showing the possibility of neuronal differentiation from pituitary cells under the influence of specific factors added to the culture media. 23,24 Moreover, in an acromegalic female patient, Ikeda et al were successful in demonstrating a monoclonality of both adenoma and neuron-like cells by an X-chromosome inactivation method.…”

“…The possibility of a transdifferentiation from normal or adenomatous pituitary epithelial cells to neuronal cells is suggested by many authors . In particular, the presence of numerous cells with morphological features intermediate between pituitary adenoma and neurons was pointed out by Horvath et al .…”

“…As an alternative hypothesis, based on experimental investigations identifying pituitary stem cells, Kontogeorgos et al suggested that, in some pituitary conditions, neuronal and adenomatous cells may derive from a common progenitor cell . A potential capacity of neuronal differentiation from pituitary adenoma cells is also suggested by a recent study by Nguyen and Lavi, showing the possible expression of nuclear neuronal antigen NeuN in common pituitary adenomas …”

“…The immunohistochemical finding, in all cases, of cytokeratins in the cytoplasm of a proportion of ganglion cells in our opinion seems to support the hypothesis expressed by some authors that a differentiation of pituitary adenoma cells into neuronal cells may occur. [7][8][9]12,16,17,21…”

Pituitary adenoma with adipose tissue: A new metaplastic variant

“…Nguyen et al suggest that the rare presence of ganglionic cells in pituitary adenomas is not the result of a separate lesion or collision of sellar tumors, as previously proposed, but a ganglionic neuronal differentiation in an endocrine neoplasm. The ganglionic cell may arise from uncommitted stem/progenitor cells that contain both neuronal and endocrine properties . For osseous metaplasia, it has been hypothesized that inflammatory, chemical or mechanical stimulation, like secondary ischemia induced by tumor compression effect, may result in the proliferation of mesenchymal cells, including not only the moderate hyperplasia of interstitial fibroblasts, but also the initiation of differentiation processes of progenitor cells into the osteoblast.…”