A 16-month-old, 2.65 kg male ruffed lemur (Varecia variegata variegata) was diagnosed with chronic recurrent multifocal osteomyelitis (CRMO) after being evaluated for shifting leg lameness over a 2 months period. Initial physical examination, complete blood count (CBC), serum biochemistry profile and survey radiographs of the thorax, abdomen, and rear legs were unremarkable. Radiographs of the left radius revealed multiple small lytic, punched out lesions in the diaphysis, and of the left tibia and fibula revealed a severe moth-eaten, lytic process affecting the entire diaphysis of the tibia, a single focus of lysis in the diaphysis of the fibula, and lysis in the calcaneus. Identical lesions were found on subsequent films involving the entire diaphysis of the left femur and proximal metaphysis of the right ulna. The tibial and ulnar lesions were biopsied using a Michelle trephine (Sontec Instruments, Englewood, CO, USA). A diagnosis of sterile pyogranulomatous osteomyelitis was made on histologic examination. No evidence of neoplasia or an infectious agent could be found on histologic examination of biopsy tissues with H&E, PAS, Gram and acid-fast stains. Biopsy material was negative for growth of aerobic, anaerobic, fungal, and mycobacterial organisms.
The diagnosis of CRMO-like disease was reached based on the criteria used in humans:2 clinical, radiographic and histologic signs with an absence of an infectious etiology. The decision was made to treat with nonsteroidal anti-inflammatories (NSAID), based on favorable response reported in humans,1 their ease of administration, and ready availability. The lemur received oral aspirin (10 mg/kg PO q24h for 7 months). During this time period there was resolution in his lameness and no new lesions were found on recheck radiographs taken at 8-week intervals. Radiographically, the lesions resolved slowly as their appearance became more sclerotic than lytic. Although post-treatment biopsies were not performed, 18 months after the first acute lameness attributed to CRMO-like disease, and 10 months after discontinuation of NSAID therapy, the lemur remains clinically asymptomatic.
1. Gallagher K, Roberts R, MacFarlane J, Stiehm E. Treatment of chronic recurrent multifocal osteomyelitis with interferon gamma. J Ped. 1997;131:470–472.
2. Girschick H, Krauspe R, Tschammler A, Huppertz H. Chronic recurrent osteomyelitis with clavicular involvement in children: diagnostic value of different imaging techniques and therapy with non-steroidal anti-inflammatory drugs. Eur J Pediatr. 1998;157:28–33.