Clival Ectopic Pituitary Adenoma Mimicking a Chordoma: Case Report and Review of the Literature

Figure 4

Pathologic evaluation, all at 20x magnification. (a) Histologic sections demonstrate an epithelial neoplasm composed of monomorphic cells with increased nuclear to cytoplasmic ratios and prominent nucleoli. (b) Immunohistochemical staining positive for synaptophysin. (c) Prolactin diffusely and strongly labels the neoplastic cells. (d) The proliferation index is approximately 2% on Ki-67 staining.

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(b)

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