PMC9339988_01
Pituitary adenoma, cat. Postcontrast transverse CT image of the skull in soft tissue window. An 8.6 by 8.3 by 6.8 mm mass (arrow) is noted at the anatomical region of the pituitary gland. A slice thickness of 0.62 mm was used.
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F1
Pituitary adenoma, cat. An imprint smear of the surgically excised pituitary mass revealed moderate numbers of neuroendocrine neoplastic cells arranged individually or in small aggregates. Cells have round to pleomorphic nuclei and a pale gray cytoplasm with poorly distinct borders and occasional vacuolization. The chromatin is finely stippled and contains multiple prominent nucleoli. Anisokaryosis is moderate to marked and occasional micronuclei are noted (arrow). Wright's-Giemsa, 10 x (upper left) and 50 x objective lenses.
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F2
Findings were interpreted as neuroendocrine neoplasia (Figure 2).
Pituitary adenoma, cat. (a) The center of the tissue contains a non-encapsulated mass consisting of nests and cords of a monomorphic population of cells compressing the peripheral parenchyma with scant, acute hemorrhage (4 x objective lens). (b) Densely-packed sheets of well-differentiated, brightly eosinophilic, granular cells with large central nuclei and prominent, single nucleoli (20 x objective lens). Hematoxylin-eosin.
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F3
Mitotic figures were rare (Figure 3).
Pituitary adenoma, cat. (a) The reticulin network is lost within the neoplasm and is still present in the compressed, peripheral pituitary tissue. (b) The cytoplasmic granules within the adenoma lack staining with PAS. (c) Clusters of cells throughout the adenoma have faint, cytoplasmic immunoreactivity to growth hormone (GH). GH positive control cells (inset).
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F4
Reticulin staining revealed a loss of reticular network within the neoplasm with respect to the compressed peripheral, non-neoplastic tissue (Figure 4), and the granules did not stain with PAS (Figure 4). Growth hormone immunohistochemistry revealed many clusters of cells with faint or weak cytoplasmic immunoreactivity within the neoplasm (Figure 4) similar to that in the control.