Diverticulosis and Colonic Leiomyosarcoma in an Aged Rhesus Macaque

Abstract

A clinically normal 30-year-old female rhesus macaque (Macaca mulatta) was acquired from the Harlow Primate Laboratory at the University of Wisconsin in Madison. In 1959, the macaque, then approximately 1 year old, arrived at the Harlow Laboratory where she gave birth to eight infants between 1964 and 1979. She was maintained at Harlow in either a nuclear family (one mate and offspring) or in single-caged housing and received a standard diet of Purina Monkey Chow with occasional fruit. Subsequent to acquisition by the Division of Comparative Medicine at Johns Hopkins University, she was euthanatized as a normal control in a study on aging.Gross examination revealed numerous diverticula randomly distributed along the length of the large intestine. These contained fecal material superficially in their lumina, with deeper, greenish-white solid cores (fecoliths). There was also a small, firm, 75 mm homogeneous tan colonic mass near the ileocecocolic junction that appeared to wrap around the wall of the colon and merge imperceptibly with the colonic musculature. It was unassociated with t e diverticula. Other gross findings included valvular endocar 'osis and pulHistologically, the diverticula were lined by normal-appearing but compressed colonic epithelium with a moderate nonsuppurative lamina proprial infiltrate. The walls of the diverticula were partially or totally absent of muscular layers at their deepest borders (Fig. 1); the muscularis mucosa and submucosal tissues abutted directly onto the peritoneal fat. The luminal cores consisted of a laminated hyalinized material without cellular definition near the epithelial border, with more superficial fecal material and mixed colonies of bacteria. The colonic mass (Fig. 2) consisted of a homogeneous population of spindle shaped cells arranged in interlacing, disorganized dense bundles or sheets that palisaded around the circumference of one bowel loop, directly abutting on the muscularis mucosa (Figs. 2, 3). There were also areas where tumor cells penetrated the muscularis mucosa and infiltrated the lamina propria. The cells had plump, vesicular, round to elongated nuclei, often with blunted, squarish ends, and multiple small nucleoli. Occasional enlarged and multinucleated cells were seen. Cell borders were indistinct but cytoplasm provided a eosinophilic background. Stroma was minimal. Mitotic figures were present but uncommon. With Masson's trichrome, the tumor cells were red, and with phosphotungstic acid hematoxylin they were muddy blue. No striations were observed. There was no evidence of vascular invasion or metastasis. monary anthracosis.

Nonhuman Primates

“…These blind pouches may increase with age and trap fecal matter predisposing animals to constipation and impaction (Bunton and Bacmeister, 1989). These blind pouches may increase with age and trap fecal matter predisposing animals to constipation and impaction (Bunton and Bacmeister, 1989).…”

What Is Your Diagnosis?

“…2 Diverticulosis of the colon is considered to be common in people from Western societies, described in up to 50% of the population more than 60 years of age. 3 It has also been reported in the vermiform appendix of people, although occurrence is rare.…”

Immunohistochemical and morphological features of a small bowel leiomyoma in a black crested macaque (Macaca nigra)

“…However, other kind of tumor such as schwannoma [5], gastrointestinal stromal [6,7], leiomyosarcoma [8] and a poorly differentiated sarcoma [9], were also reported.…”