PMC4739142_01
Appearance of the stallion before (a) and after (b) the onset of pituitary pars intermedia dysfunction
(PPID). The stallion had already molted by May 31, 2013, at the age of 20 years (a), but it had not molted
by May 31, 2014, at the age of 21 years (b).
jes-26-125-g001.jpg
PMC4739142_01_jes-26-125-g001.jpg
fig_001
A male Thoroughbred stallion that had been at stud since 9 years of age was initially examined by the author for persistent hirsutism and delayed molting in May (spring) 2014 at the age of 21 years (Fig. 1a and 1b).
CT scan cross-sectional findings of the enlarged pituitary gland of the stallion. The lengths in the
vertical and horizontal directions were 2.05, and 2.72 cm, respectively.
jes-26-125-g002.jpg
PMC4739142_01_jes-26-125-g002.jpg
fig_002
Following computed tomography imaging of the head, the pituitary gland was observed to be enlarged (Fig. 2).
Macroscopic findings of the stallion's enlarged pituitary gland, which protruded from the pituitary
fossa.
jes-26-125-g003.jpg
PMC4739142_01_jes-26-125-g003.jpg
fig_003
The crucial macroscopic findings were swelling of the pituitary gland (3.8 x 3.0 x 2.2 cm), which protruded from the pituitary fossa (Fig. 3), and atrophy of the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis; Fig. 4).
Vertical section of the stallion's pituitary gland. Pituitary adenoma was noted in the intermediate lobe
and the excluded anterior and posterior lobes. The open arrows indicate the boundary of the anterior lobe
and intermediate lobe.
jes-26-125-g004.jpg
PMC4739142_01_jes-26-125-g004.jpg
fig_004
The intermediate lobe was hyperplastic in the vertical section (Fig. 4).
Histopathological image of the tumor cells that were derived from the intermediate lobe in the pituitary.
The tumor cells had an oval nuclei and a highly spindle-shaped cytoplasm that was amphophilic and/or
eosinophilic, and the alignments of cells were radial at the center of small vessels with a palisade or
acinar alignment.
jes-26-125-g005.jpg
PMC4739142_01_jes-26-125-g005.jpg
fig_005
The tumor cells had an oval nuclei and a highly spindle-shaped cytoplasm that was amphophilic and/or eosinophilic, and the alignments of cells were radial at the center of small vessels with a palisade or acinar alignment (Fig. 5).
PMC4739142_02