January 2019

Signalment Slide A (JPC #1414004):  A female rhesus monkey (Macaca mulatta)

HISTORY:  This monkey had a poor appetite for several months. 

HISTOPATHOLOGIC DESCRIPTION:  Colon with adjacent mesentery and lymph node:  Transmurally disrupting and markedly expanding the wall of the colon up to 12 mm, primarily affecting the tunica muscularis and submucosa, and extending into the mesentery are multiple, unencapsulated, infiltrative islands of tortuous endometrial glands surrounded by abundant, densely cellular endometrial stroma.  The endometrial glands are lined by simple to pseudostratified columnar, ciliated epithelial cells with a moderate amount of clear to pale eosinophilic cytoplasm and prominent basilar vacuolation.  Nuclei are anti-basilar and oval with finely stippled chromatin and frequently exhibit nuclear regimentation.  The endometrial stroma is composed of spindle cells with indistinct cell borders, scant eosinophilic, fibrillar cytoplasm and an oval to elongate nucleus with finely stippled chromatin.  Rarely glands contain moderate numbers of macrophages, neutrophils, erythrocytes, and cellular debris.  Endometrial stroma within the mesenteric adipose tissue surrounds a focus of hemorrhage, degenerate neutrophils and necrotic debris and is bound by haphazardly arranged reactive fibroblasts and collagen.  The mesenteric lymph node contains increased histiocytes within the paracortical and medullary sinuses, which often demonstrate erythrophagocytosis (draining hemorrhage).

MORPHOLOGIC DIAGNOSIS:  Colon and adjacent mesentery:  Endometriosis, rhesus macaque (Macaca mulatta), nonhuman primate.

CONDITION:  Endometriosis

Signalment Slide B (JPC #1850940):  A 9-year-old female Siamese cat

HISTORY:  This cat had intermittent vomiting. 

HISTOPATHOLOGIC DESCRIPTION:  Uterus:  Diffusely the inner circular layer of the myometrium is thickened up to 1.5 cm by islands of endometrial glands and endometrial stromal elements (adenomyosis), which disrupt and replace smooth muscle bundles.  The epithelium of glands occasionally forms papillary fronds, and ectatic lumina often contain variable amounts of eosinophilic homogenous material (secretory product) admixed with cellular debris and moderate numbers of neutrophils and macrophages.  The uterine lumen contains a large dense aggregate of degenerate neutrophils admixed with necrotic debris and sloughed epithelial cells (pyometra).  The endometrium is multifocally thickened up to two times normal by mildly hyperplastic, ectatic and tortuous endometrial glands (cystic endometrial hyperplasia).  There is multifocal squamous metaplasia of the endometrial epithelium and glandular epithelium with scattered intracellular edema.  There are rare lymphocytes, plasma cells and neutrophils within the uterine stroma.

MORPHOLOGIC DIAGNOSIS:  Uterus:  Adenomyosis, with multifocal cystic endometrial hyperplasia, and suppurative endometritis (pyometra), Siamese, feline.

CONDITION:  Adenomyosis









Gross differential diagnosis for uterine wall lesions and/or serosa of abdominal viscera:

Histologic differential diagnosis:



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