Myelomonocytic Leukemia in an Orangutan

Abstract

We report a ca se of spo n ta neous my elom on ocytic leukemi a in a n ora ngu ta n ( Pongo pygma eus). We believe thi s is th e first rec orded hematogen ou s m ali gn ancy in thi s spec ies. A Bly mp ho id cell line producin g an E BV-like herpes virus [l Z] was derived from the o ra ng u ta n.The ora ngu tan , a wild-born 13-year-old fem al e, had been at the Los Angeles Z oo since 1965. III health was first noted in F ebrua ry 1976 a nd she was kill ed 8 months la ter a fter a clin ica l co u rse characterized by slow deterioration . Sh e rece ived neither che mo the rapy , radiotherapy, nor blood transfu sion s. The hem oglobin was co ns isten tly ab out 6.0 gm /dl, plat elets were increased in number and the white blood cell co u n t ran ged between 7,000 a nd 26,000 with primitive mon onuclear cells rep eatedly found in th e peripheral blood a nd bone marrow . Cy to chem ica l stud ies on peripheral blood buffy co a t and bon e marrow indicated th e diagn osis o f myel omon ocyti c leukemia by sho wing th at ma ny o f th e a bno rm a l mon onuclear cell s stained stro ng ly for histi ocytic-m on ocytic ma rkers (ac id ph osphat ase and non spe cifi c es te rase) and for gr anulocyti c markers (Sudan black B, per oxid ase and chlo roaceta te es teras e). The persisten ce of adequate me gakaryoc yte s de sp ite de creased er ythro-a nd gran ulop oie sis in th e bone m arrow, together with the mi ld clinical signs a nd lack o f detectable orga no mega ly o r ade no pa thy , sugges ted a su ba cute form o f thi s di sease.G ross findings a t a u to psy we re unremark ab le a part from two incidental hyd at id cysts in th e liver, o ne active and o ne inactive . Spleen, liver a nd lymph nodes wer e not en la rged , unduly soft, o r di scolored nor we re leukem ic infiltrate s visible in a ny tissue . T he bon e marrow from multiple sites wa s gen erally pale and sclero tic.T issue sec tions, sta ine d with hemat oxylin and eos in aft e r fo rmalin fixati on a nd par affin embedding, sho wed unequivocal mic ro scopi c ev ide nce o f myelopro liferative di sea se. In virtu all y every o rgan, including the brain, perivascular mon onuclear leukemi c infiltrates wer e not ed ( fig . I, 2). Leukemic cell s infiltrated the bon e m arrow, lymph nodes, and splee n to a m ajor extent, de spite th e lack of o rga n en largement. In th e bone marrow the leukemic infiltrates were spotty and the intervening marrow sho wed di ffu se sligh t fibrosis a nd an ove ra ll paucity o f normal hematop oietic ce lls. In th e lymph nodes a nd sp lee n th e infiltrates occur red p rimarily in the medullary co rds and red pulp, resp ectiv ely, wi th so me spa ring o f residual lymphoid nodules. T he only infiltra tes in the live r a nd kidney were perivascular in the port al tra cts and medulla, respe ctively. C h loro ac etate esterase stai ni ng of spleen a nd lymph node sec tio ns confirmed the gr anulocytic nature o f the leu kem ic infiltrate . Extra med u llary hematopoiesis wa s not noted at any site. Sec tion s of th e inactive...

Neoplasms and Proliferative Disorders in Nonhuman Primates

“…There is also a report of a 13-year-old wild-caught female orangutan that developed subacute myelomonocytic leukemia. An Epstein-Barrlike herpesvirus was isolated from lymphocytes from this animal, and no retroviral activity (by reverse transcriptase) was found [36]. The single benign hematopoietic tumor in this survey was a splenic hemangioma.…”

Neoplasia and Proliferative Disorders of Nonhuman Primates

“…Spontaneous leukemias are uncommon and include the following: eosinophilic myelocytoma in an owl monkey (A. trivirgatus) ; erythroleukemia in a chimpanzee (P. troglodytes) (McClure et al, 1974); monocytic leukemia in a galago (Galago argentatus) (Holscher et al, 1984); and granulocytic leukemia in a white-handed gibbon (H. lar) (DePaoli et al, 1973). Cases of myelomonocytic leukemia have been reported in an orangutan (P. pygmaea) (Gardner et al, 1978) and a capuchin monkey (C. apella) (Bennett et al, 1981). Myeloproliferative disorders have been described in a cotton-top tamarin (S. oedipus) (Kirkwood and James, 1983) and a pygmy marmoset (P. pygmaea) (Lowenstine, 1986).…”

A Chimpanzee Genome Project Is a Biomedical Imperative: Figure B1.

“…Although the numbers of welldocumented autopsies on great apes are relatively small (in the hundreds), several factors suggest that this apparent difference is not due to ascertainment bias. First, there are several reports of apes having leukemias and lymphomas (Manning and Griesemer 1974;Gardner et al 1978), which comprise only a minority of malignancies in humans. Second, although age is certainly a factor affecting carcinoma incidence, great apes often live into their forties and fifties (and even sixties) in captivity.…”