SHORT PAPER Pineocytoma in a Lowland Anoa (Bubalus depressicornis) J. Williams * , U. Hetzel * , J. Chatterton † and J. Chantrey * * Department of Veterinary Pathology, Faculty of Veterinary Science, University of Liverpool, Liverpool L69 7ZJ and † Chester Zoo, Caughall Rd, Upton, Chester CH2 1LH, UK Summary This report describes the first case of a pineocytoma in an 18-year-old female lowland anoa (Bubalus depressi- cornis). The tumour grossly appeared as a focal, non-infiltrative, yellowetan, encapsulated mass occupying the normal anatomical location of the pineal gland. Microscopical, immunohistochemical and electron micro- scopical findings were consistent with a diagnosis of pineocytoma an entity not previously described in this member of the buffalo subgenus species. Ó 2010 Elsevier Ltd. All rights reserved. Keywords: brain; Bubalus depressicornis; lowland anoa; pineocytoma In mammals the pineal gland develops from an evag- ination of the roof of the third ventricle and is located within the midline of the brain immediately rostro- dorsal to the superior colliculus and caudoventral to the stria medullaris, between the thalamic bodies. Its primary function is that of a neuroendocrine trans- ducer, central to controlling circadian rhythms with darkness inducing pinealocytes to synthesize melato- nin from tryptophan, which induces sleep, possibly through its effects on thermoregulation (Van Den Heuvel et al., 1997). In reptiles the organ is situated just beneath the surface of the skin and is directly con- nected to the parietal eye, functioning as a direct pho- toreceptive organ, whereas in mammals the organ receives afferent neuronal input from the retina via a subset of melanopsin containing retinal ganglion cells and the suprachiasmatic nucleus (Berson et al., 2002), stimulating release of melatonin in the hours of darkness. In seasonal breeding animals, the pineal gland is also implicated in the induction of sexual ac- tivity through recognition of seasonally increasing or decreasing day length (Arendt, 1998). The lowland anoa (Bubalus depressicornis) is a small ruminant of the family Bovidae and can have a life- span in captivity of up to 30 years. The lowland anoa is classified by the International Union for the Conservation of Nature and Natural Resources (IUCN) as endangered; wild populations are in de- cline due to habitat loss and hunting. Lowland anoas are native only to Sulawesi in Indonesia and the is- land of Buton off the south-eastern coast of Sulawesi. They are browsers of various forest habitats including mangrove, swamp and primary and secondary low- land forests. Despite their name, they have been found at elevations of up to 1,000 m above sea level in moun- tainous areas. They are thought to be a separate spe- cies to the mountain anoa (Bubalus quarlesi), although the exact relationship between these species is not established (Burton et al., 2005). The anoa in this case was an 18-year-old captive- bred female, 81 kg in body weight, which had been in the zoological collection for 8 years. She presented collapsed and in lateral recumbency in the outdoor enclosure. Clinical examination revealed reduced mentation with an inconsistent response to external stimuli, increased vocalization and rectal tenesmus. There was a clinical history of increased aggression and profuse, watery diarrhoea of 48 h duration. There had been intermittent episodes of diarrhoea, approximately once or twice per month, for the previ- ous 6 months. These episodes were not associated with haematochezia, tenesmus or any other adverse Correspondence to: J. M. Williams (e-mail: [email protected]). 0021-9975/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jcpa.2010.08.011 J. Comp. Path. 2011, Vol. 144, 227e230 Available online at www.sciencedirect.com www.elsevier.com/locate/jcpa
Transcript
J. Comp. Path. 2011, Vol. 144, 227e230 Available online at www.sciencedirect.com
www.elsevier.com/locate/jcpa
SHORT PAPER
Pineocytoma in a Lowland Anoa(Bubalus depressicornis)
Cor
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J. Williams*, U. Hetzel*, J. Chatterton† and J. Chantrey*
*Department of Veterinary Pathology, Faculty of Veterinary Science, University of Liverpool, Liverpool L69 7ZJ and†Chester Zoo, Caughall Rd, Upton, Chester CH2 1LH, UK
resp
1-99
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Summary
This report describes the first case of a pineocytoma in an 18-year-old female lowland anoa (Bubalus depressi-cornis). The tumour grossly appeared as a focal, non-infiltrative, yellowetan, encapsulated mass occupyingthe normal anatomical location of the pineal gland. Microscopical, immunohistochemical and electron micro-scopical findings were consistent with a diagnosis of pineocytoma an entity not previously described in thismember of the buffalo subgenus species.
In mammals the pineal gland develops from an evag-ination of the roof of the third ventricle and is locatedwithin the midline of the brain immediately rostro-dorsal to the superior colliculus and caudoventral tothe stria medullaris, between the thalamic bodies.Its primary function is that of a neuroendocrine trans-ducer, central to controlling circadian rhythms withdarkness inducing pinealocytes to synthesize melato-nin from tryptophan, which induces sleep, possiblythrough its effects on thermoregulation (Van DenHeuvel et al., 1997). In reptiles the organ is situatedjust beneath the surface of the skin and is directly con-nected to the parietal eye, functioning as a direct pho-toreceptive organ, whereas in mammals the organreceives afferent neuronal input from the retina viaa subset of melanopsin containing retinal ganglioncells and the suprachiasmatic nucleus (Berson et al.,2002), stimulating release of melatonin in the hoursof darkness. In seasonal breeding animals, the pinealgland is also implicated in the induction of sexual ac-tivity through recognition of seasonally increasing ordecreasing day length (Arendt, 1998).
The lowland anoa (Bubalus depressicornis) is a smallruminant of the family Bovidae and can have a life-span in captivity of up to 30 years. The lowland
anoa is classified by the International Union for theConservation of Nature and Natural Resources(IUCN) as endangered; wild populations are in de-cline due to habitat loss and hunting. Lowland anoasare native only to Sulawesi in Indonesia and the is-land of Buton off the south-eastern coast of Sulawesi.They are browsers of various forest habitats includingmangrove, swamp and primary and secondary low-land forests. Despite their name, they have been foundat elevations of up to 1,000 m above sea level inmoun-tainous areas. They are thought to be a separate spe-cies to the mountain anoa (Bubalus quarlesi), althoughthe exact relationship between these species is notestablished (Burton et al., 2005).
The anoa in this case was an 18-year-old captive-bred female, 81 kg in body weight, which had beenin the zoological collection for 8 years. She presentedcollapsed and in lateral recumbency in the outdoorenclosure. Clinical examination revealed reducedmentation with an inconsistent response to externalstimuli, increased vocalization and rectal tenesmus.There was a clinical history of increased aggressionand profuse, watery diarrhoea of 48 h duration.There had been intermittent episodes of diarrhoea,approximately once or twice per month, for the previ-ous 6months. These episodes were not associated withhaematochezia, tenesmus or any other adverse
clinical signs, and would typically self-resolve within24e48 h. Further diagnostics, including serum bio-chemistry, haematological examination, radiographyand ultrasonography of the abdomen, were unre-markable. Due to the rapid and continuing clinicaldeterioration, the animal was humanely destroyedwith an intravenous injection of pentobarbitalsodium (140 mg/kg, Pentobarbital; J.M. LoveridgeLtd., Southampton, UK) followed by necropsyexamination.
The animal was in poor nutritional condition andother post-mortem findings included multifocal mildto moderate fibrinofibrous pericardial, pleural andperihepatic adhesions. The renal sinuses contained ge-latinous material interpreted as serous atrophy of fat.On examination of the brain, there was a relativelylarge, 2 cm diameter, non-infiltrative, yellowetan,well-demarcatedmass occupying the normal anatom-ical location of the pineal gland, within the quadrige-minal cistern, rostrodorsal to the superior colliculusand caudoventral to the stria medullaris, boundedventrally by the tectum of the mesencephalon andby the hippocampal gyri dorsolaterally (Fig. 1).
Samples of the mass and representative areas of thebrain were prepared and embedded routinely in par-affin wax for histopathological examination. Sections(3e5 mm) were stained with haematoxylin and eosin(HE). Selected sections of the mass were also stainedwith Masson’s fontana to demonstrate melanin andperiodic acid-Schiff (PAS) to demonstrate glycogen,or were used for immunohistochemical examination.Immunohistochemistry (IHC) was performed on
Fig. 1. Brain after formalin fixation. Coronal section at the level ofthe thalamus demonstrating the midline, well circum-scribed, non-infiltrative, 2 cm diameter, yellowetan massbetween the hippocampal gyri and immediately dorsal tothe superior colliculus. Square indicates region from whichphotomicrograph (Fig. 2) is taken.
the pineal mass using antibodies (all from DakoCyto-mation, Ely, Cambridgeshire) specific for vimentin(mouse anti-pig vimentin; clone V9), glial fibrillaryacidic protein (GFAP; rabbit anti-GFAP), melan-A(mouse anti-human melan-A; clone A103), synapto-physin (mouse anti-cow synaptophysin; cloneSY-38), pan-cytokeratin (mouse anti-human-cyto-keratin; clone AE1/AE3), S-100 protein (rabbitanti-cow S-100 protein), neurofilament (mouse anti-human neurofilament protein; clone 2F11) and neu-ron-specific enolase (NSE; mouse anti-human NSE;clone BBS/NC/VI-H14). All of these reagents havebeen shown to cross-react with canine tissues and la-belling was performed according to previously pub-lished protocols (Kipar et al., 1995).
Transmission electron microscopy was performedon formalin-fixed tissue after post-fixation in 4%paraformaldehyde and 2.5% glutaraldehyde ina sodium caccodylate buffer and secondary fixationin osmium tetroxide.
Microscopically, the mass was non-infiltrative andlined at its outer aspect by the meninges. Themass ex-hibited marked multifocal mineralization and wascomposed of nests, lobules and palisades of closelypacked, relatively monomorphic polyhedral cells,which occasionally formed large pineocytomatous ro-settes within a pale eosinophilic fibrillar stroma(Fig. 2). Individual cells were approximately 15 mmin diameter, with moderate amounts of clear cyto-plasm, distinct cell borders and a large (8 mm) cen-trally located, round, hyperchromatic nucleus withstippled chromatin. Mitoses were rarely observedand there was prominent medial calcification of arte-rioles. Occasional karyomegaly was recognized andoften the neoplastic cells exhibited intracytoplasmic
Fig. 2. Section of neuropil at the tumour margin. Normal neuro-parenchyma (left) borders the neoplastic process (right),which exhibits occasional pineocytomatous rosettes(arrow). HE.
Fig. 3. Immunohistochemical expression of synaptophysin. Neo-plastic cells exhibit positive cytoplasmic labelling andstrongly positive fibrillary zones (arrows).
Pineocytoma in a Lowland Anoa 229
brown granular pigment (melanin). Amild to moder-ate, multifocal, non-suppurative encephalitis withlymphoplasmacytic cuffing was also recognized. Dif-fusely, neoplastic cells and fibrillary zones exhibitedstrong immunolabelling for synaptophysin (Fig. 3),NSE, and focally, occasional cells showed positive ex-pression of GFAP and neurofilament. Neoplastic cellsdid not exhibit labelling for melan-A or vimentin.Ultrastructural examination was limited due tomarked fixation artefacts; however, neoplastic cellsdid exhibit electron-lucent nuclei and a mitochon-dria-rich, variably vacuolated to granular, cyto-plasm. Occasional tight gap junctions were observedbetween adjacent cells.
Other histological findings includedmild tomoder-ate multifocal mural and perivascular lymphoplas-macytic epicarditis and endocarditis with occasionalmyocardial sarcocysts (Sarcocystis spp.), moderatelymphoplasmacytic and proliferative abomasitis,moderate, multifocal, chronic plasmalymphocytic in-terstitial nephritis andmildmultifocal periportal lym-phoplasmacytic hepatitis. Bacteriological isolation ofStreptococcus bovis biotype II/4 from pericardial fluid,liver and lung, was consistent with a late stage strep-tococcal septicaemia.
Tumours of the pineal gland are broadly categorizedas parenchymal pineal tumours (PPTs) or germ cell tu-mours and are very rare in domestic animals. PPTs aresubcategorized as pineocytomas or pineoblastomas, ormixed pineocytomaepineoblastoma. They are consid-ered a rare tumour in man and extremely rare in ani-mals (Koestner and Higgins, 2002), having only beendescribed with any frequency in laboratory rats, withsingle reports in other species including the cow, goat,horse, fox, zebra, chicken and cockatiel (Koestner
et al., 1999; Koestner and Higgins, 2002; Laperle andCapen, 2007). In man, tumours of the pineal glandare most commonly diagnosed in infants or in youngadults (Mena et al., 1995) and the classification systemalso incorporates parenchymal pineal tumours of inter-mediate differentiation (PPID) with characteristics ofboth pineocytoma and pineoblastoma (Louis et al.,2007).
The morphological and immunohistochemicalfindings in the present case were consistent with a di-agnosis of pineocytoma, which is defined by theWorld Health Organization as a non-infiltrative,highly cellular neoplasm with lobular architecturecomposed of polygonal cells, which form pseudoro-settes, and that may form irregular fibrillary zones re-ferred to as pineocytomatous rosettes. IHC typicallyshows cells in the fibrillary zones to be positive for syn-aptophysin (Mena et al., 1995; Koestner et al., 1999;Laperle and Capen, 2007), NSE and, occasionally,neurofilament protein (Koestner et al., 1999), as inthis case. The findings were considered less consistentwith the alternative diagnosis of pineoblastoma; themalignant counterpart to the pineocytoma, whichin contrast typically lacks lobular architecture and ex-hibits greater pleomorphism, multifocal necrosis andlocally invasive behaviour.
Acknowledgments
J.Williamswas funded by theRCVSTrust as a SeniorClinical Scholar in Veterinary Pathology at the timeof this work. The support of the RCVS Trust is grate-fully acknowledged. We are grateful to the keepingstaff at Chester Zoo for the behavioural informationsupplied.
References
Arendt J (1998) Melatonin and the pineal gland: influenceon mammalian seasonal and circadian physiology.Reviews of Reproduction, 3, 13e22.
Berson DM, Dunn FA, Takao M (2002) Phototransduc-tion by retinal ganglion cells that set the circadianclock. Science, 295, 1070e1073.
Burton JA, Hedges S, Mustari AH (2005) Taxonomic sta-tus, distribution and conservation of the lowland anoaBubalus depressicornis and mountain anoa Bubalus quarlesi.Mammal Review, 35, 25e50.
Kipar A, Baumgartner W, Burkhardt E (1995) Round cellsarcomas of possible myelomonocytic origin localized atthe lip of aged dogs. Zentralbl Veterinarmed A, 42,185e200.
Koestner A,Higgins RJ (2002) Tumours of the nervous sys-tem. In: Tumours in Domestic Animals, 4th Edit,DJ Meuten, Ed., Iowa State Press, Ames, pp. 728e729.
Koestner A, Bilzer T, Fatzer R, Schulman FY,Summers BA et al. (1999) Histological Classification of
230 J. Williams et al.
Tumours of the Nervous System of Domestic Animals. ArmedForces Institute of Pathology, Washington DC. p. 27.
LaperleKM,CapenCC (2007)Disorders of the pineal gland.In: Pathologic Basis of Veterinary Disease, MD McGavin,JF Zachary, Eds., Mosby Elsevier, St Louis, pp. 739.
Louis DN, Ohgarki H, Wiestler OD, Cavenee WK,Burger PC et al. (2007) The 2007 WHO classificationof tumours of the central nervous system. Acta Neuropa-
McCarthy WF (1995) Tumours of pineal parenchymalcells: a correlation of histological features, including
nucleolar organizer regions, with survival in 35 cases.Human Pathology, 26, 20e30.
Van Den Heuvel CJ, Reid KJ, Dawson D (1997) Effect ofatenolol on nocturnal sleep and temperature in youngmen: reversal by pharmacological doses of melatonin.Physiology and Behaviour, 61, 795e802.
