Solitary Osteochondroma in a Ring-Tailed Lemur (Lemur catta)

A 20-y-old, male, ring-tailed lemur (Lemur catta) presented with a large, firm mass on the proximal caudolateral left femur. The animal displayed no clinical signs associated with the mass. Radiographs revealed a mineralized mass protruding from the femur, with an intact femoral cortex. Histopathology diagnosed osteochondroma in view of the presence of a peripheral layer of cartilage with progressive endochondral ossification and typical remodeling of bony trabeculae. The mass grew quickly after the initial biopsy, and a second surgery to debulk 95% of the tumor was performed. Histopathologic features of the larger samples were similar to those of the initial biopsies, with the cartilage layer being discontinuous and development of bone from some borders progressing directly from a periost-like layer. Nineteen months after the second surgery, the mass had regrown and extended further proximally on the femur toward the epiphysis, but the animal remained asymptomatic, and additional debulking was not attempted. This report is the first description of an osteochondroma in a prosimian and describes unique behavior of the tumor compared with osteochondromas found in humans, dogs, and cats.

Surgical correction of an arteriovenous fistula in a ring-tailed lemur (Lemur catta)

A 10-y-old ovariohysterectomized ring-tailed lemur (Lemur catta) was presented for exacerbation of respiratory signs. The lemur had a history of multiple examinations for various problems, including traumatic lacerations and recurrent perivulvar dermatitis. Examination revealed abnormal lung sounds and a femoral arteriovenous fistula with a palpable thrill and auscultable bruit in the right inguinal area. A diagnosis of congestive heart failure was made on the basis of exam findings, radiography, abdominal ultrasonography, and echocardiography. The lemur was maintained on furosemide until surgical ligation of the fistula was performed. Postoperative examination confirmed successful closure of the fistula and resolution of the signs of heart failure. Arteriovenous fistulas are abnormal connections between an artery and a vein that bypass the capillary bed. Large arteriovenous fistulas may result in decreased peripheral resistance and an increase in cardiac output with consequent cardiomegaly and high output heart failure. This lemur's high-flow arteriovenous fistula with secondary heart failure may have been iatrogenically induced during blood collection by prior femoral venipuncture. To our knowledge, this report is the first description of an arteriovenous fistula in a prosimian. Successful surgical correction of suspected iatrogenic femoral arteriovenous fistulas in a cynomolgus monkey (Macaca fascicularis) and a rhesus macaque (Macaca mulatta) have been reported previously. Arteriovenous fistula formation should be considered as a rare potential complication of venipuncture and as a treatable cause of congestive heart failure in lemurs.

Evaluation of the aged female baboon as a model of pelvic organ prolapse and pelvic reconstructive surgery

OBJECTIVE

This study examines the baboon as an animal model of pelvic organ prolapse (POP) by describing the pelvic floor anatomy and adapting human clinical assessment tools.

STUDY DESIGN

The pelvic anatomy of an adult female baboon was observed at necropsy, and comparisons were made to the human and squirrel monkey. The pelvic organ prolapse quantification (POP-Q) system was used to assess vaginal support in 12 living adult baboons, including 6 young, reproductive-age, nulligravid females (4.8 +/- 0.5 years) and 6 older, multiparous females (23.0 +/- 0.5 years).

RESULTS

The female baboon pelvic anatomy was found to have similar architecture to the human and squirrel monkey female. Six multiparous females with mean parity of 5 (range 2-8) showed no evidence of POP or differences in POP-Q measurements from 6 nulliparous females.

CONCLUSION

The POP-Q system can be used to assess female baboon vaginal support. In a sample of baboons, pelvic support loss consistent with POP was not identified. As the pelvic anatomy is similar to the human female, the baboon may prove useful for evaluating surgical materials and for modeling pelvic floor reconstructive surgeries.

Interstitial cell tumor in a black-and-white ruffed lemur (Varecia variegatus variegatus)

A 14.5-yr-old, male black-and-white ruffed lemur (Varecia variegatus variegatus) presented for acute enlargement of the left testicle and hemiscrotum. Physical examination also revealed poor pelage quality with short guard hairs, sparse undercoat, and areas of alopecia. Increased aggression was also reported. A unilateral, open orchiectomy was performed, with the left testicle, epidydymis, associated vaginal tunic, and attached spermatic cord removed. Microscopic evaluation was consistent with an interstitial cell tumor, with many morphologic features similar to this neoplasm in people. No overt histopathologic criteria of malignancy were present. Following orchiectomy, gradual improvement in pelage quality was noted and was considered almost normal by 5 mo postoperative. In contrast with the aggressive preoperative behavior, the lemur was extremely submissive for 3 mo following the surgery. Gradual return to normal behavior and social status occurred over the next 2 mo. Multiple follow-up examinations and radiographs revealed no evidence of metastasis, and biopsy of the remaining testicle 4 mo later revealed no evidence of neoplasia. Serial measurements of testosterone and estradiol revealed levels within the range of those for other ruffed lemurs, as were repeated measurements taken of the remaining testicle. At 19 mo postoperative, the lemur had a coat quality considered nearly normal and maintained its historical social position in the lemur group without abnormal aggressive behavior.