Basal cell tumor or cutaneous basilar epithelial neoplasm? Rethinking the cytologic diagnosis of basal cell tumors

A 1-cm-diameter, red, raised, cutaneous mass over the dorsal surface of the left third metacarpal of a 6-year-old neutered male yellow Labrador Retriever was aspirated. The aspirate contained cohesive clusters of cells, some containing cells with increased pleomorphism. Cellular debris (some keratinized), melanin, large numbers of macrophages, a few neutrophils, and fibroblasts were also observed. The cytologic interpretation was malignant neoplasia with histiocytic inflammation. Differentials included a carcinoma or, given the melanin pigment and variable morphology of the cells, possibly malignant melanoma. Histologically, the tumor was diagnosed as a basal cell epithelioma. Neoplasms that once were lumped into the broad histologic diagnosis of basal cell tumors have since been split into distinct entities, dependent on evidence of differentiation into epidermis, trichofollicular epithelium, or sweat or sebaceous glands. Although histologic reclassification has resulted in removal of most of these entities from the original basal cell tumor category, a cytologic diagnosis of basal cell tumor continues to be used to represent the large, heterogeneous group of epidermal, trichofollicular, and adnexal skin tumors with basal cell characteristics. The case in this report demonstrates the heterogeneity of neoplasms that may be diagnosed cytologically as basal cell tumors and supports the need for cytologic criteria and nomenclature that better reflect potential variation in tissue differentiation.     

Multilobular tumour of the caudal cranium causing severe cerebral and cerebellar compression in a dog

Multilobular tumour of bone (MTB) is an uncommon tumour and is usually located in the skull. A 13-year-old mixed breed dog was presented with a two-week history of progressively worsening vestibular dysfunction and cognitive abnormalities; it appeared demented and showed asymmetric ataxia and hypermetria of all limbs. The owner opted to have the animal euthanised. Necropsy revealed a large mass occupying the right occipital, parietal and temporal bones, severely compressing the cerebellum and the right occipital lobe. Histologically, it was characterised by the presence of multiple lobules containing osteoid or cartilage and separated by fibrous septae, features typical of MTB. Lung metastases were evident. To our knowledge, this is the first report of an MTB causing both severe cerebral and cerebellar compression and the second detailed report of an MTB of the occipital bone. MTB should be included in the differential diagnosis of bone tumours as well as in cases with central vestibular disease.     

Spectral waveform analysis of major arteries in conscious dogs by Doppler ultrasonography

Normal values of arterial blood flow velocity and waveforms in major arteries of 10 healthy conscious Beagle dogs were determined using Doppler ultrasonography. Peak systolic, early diastolic, and end-diastolic velocities of the basilar artery, common carotid artery, abdominal aorta, external iliac artery, femoral artery, and peak ejection velocity of the valvular aorta were evaluated. Pulsatility index (PI) of the basilar artery and blood pressure were recorded. All arteries had a high-resistance flow pattern with triphasic flow velocity except the basilar artery, which had a low-resistance pattern. Mean peak systolic velocities of the basilar artery, common carotid artery, abdominal aorta, external iliac artery, and femoral artery were 72 +/- 19, 115 +/- 17, 121 +/- 24, 105 +/- 25, and 110 +/- 17 cm/s, respectively. The PI of the basilar artery and peak ejection velocity of the valvular aorta were 1.37 +/- 0.13 and 96 +/- 16 cm/s, respectively. Mean systolic and diastolic blood pressures were 137 +/- 13 and 78 +/- 15 mmHg, respectively. Present findings may be used as references in future studies on vascular diseases and hemodynamics in dogs.     

Zoogeographical barriers causing discontinuous osteometrical variations in the northern treeshrew skulls

Morphological variation of the skull was examined in the northern treeshrew (Tupaia belangeri) from various localities across Southeast Asia. Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct morphological characteristics compared to other populations from Thailand and Laos, and Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand plots segregation in the scatteregrams of canonical discriminant analysis. Since the skulls of the population from North Vietnam were morphologically similar to those form central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of Mekong River was not clearly confirmed. The population of the Kanchanaburi in western Thailand is clearly smaller in size compared to the other populations. The southern border of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani Line. In the northern treeshrew, which is distributed from southern China to Bangladesh and southern Thailand, we have detected osteometrical geographical variation driven by geography. These results indicate that the skull morphology in the Tupaia glis-belangeri complex distinctively differs in South Vietnam, western Thailand, and southern Thailand. The zoogeographical barrier and factor separating these districts are expected to clarify in the future.     

陕西草兔头骨形态的地理学分化

应用方差分析和判别函数的方法,系统的比较了陕西从北到南3个地区的草兔种群在头骨形态上的异同。结果表明在所测量的44个头骨性状中,陕北与关中、陕北与陕南、关中与陕南的草兔种群已分别在30、26及2个头骨变量上存在明显差异,陕北明显与关中和陕南的头骨形态区分开。逐步判别函数分析显示鼻骨长、颧宽、听泡间距等变量是导致该3个地区草兔种群头骨形态发生分化的主要变量。由于草兔是陕西3个地区内部一种数量较多的常见物种,分析认为其头骨形态的种群分化可能与不同地区的环境差异导致的选择压力不同有关。     

SKULL RADIOGRAPHS: SILVER IMPREGNATION AS AN INTERPRETATION AID

Individual skull bones of newly killed young cats were stained with an aqueous solution of 0.5% silver nitrate. These bones became blackened grossly and more radiodense than adjacent unstained skull bones. It was possible to correlate the gross and radiographic appearance of selected bones stained with silver nitrate. This was a useful teaching aid.     

Calvarial Osteoma with Cranial Vault Invasion in the Skull of a Ferret (Mustela putorius furo)

Osteoma is an uncommon tumor found in various animal species and is particularly rare or underreported in ferrets. A 2-year-old neutered male ferret (Mustela putorius furo) presented with an asymmetrical firm mass affecting the right dorsolateral skull. Radiographic images and computed tomography scans revealed a well-marginated mineralized mass involving the dorsal right calvarium that was growing concentrically into the cranium. A surgical biopsy sample was obtained and yielded a cytological diagnosis of sarcoma with reactive osteoblasts and osteoclasts and a histopathological diagnosis of osteoma. It was suspected that only the outer bony rim of the mass was submitted for histopathological evaluation, thereby adversely affecting the diagnostic quality of the sample. Based on interpretation of the combined imaging, cytological, and histopathological findings, a multilobular tumor of bone was suspected. Because of reduction in quality of life, the animal was euthanized 4 months after presentation, and postmortem examination yielded a definitive diagnosis of osteoma. This is the first report of an osteoma with cranial vault invasion in a ferret and is one of very few reports of this tumor diagnosed in this species. Lack of neurological signs in the patient, marked and extensive growth of the mass over several months, and the similar clinical appearance to other bony tumors leading to diagnostic ambiguity contributed to the distinctiveness of this case.     

Domestic dog skull diversity across breeds,breed groupings,and genetic clusters

Domestic dogs have become a model organism for studying the extent and consequences of morphological diversity, especially in the skull. It has been demonstrated that Cephalic Index (CI, skull width/skull length) correlates with central concentration of ganglion cells in the retina and with ventral rotation of the cerebral hemispheres. These changes may be reflected in the behavior of breeds with different skulls shapes. This study explored skull variation in the breed groups (n = 7) described by the Australian National Kennel Club to determine if CI differed significantly among the breed groups; groups were expected to differ not least in behavior. The CI of 12 representative dogs (females, n = 6; males, n = 6) of the most popular breeds (n = 80; total n = 960 dogs) were measured. Multivariate analysis of variance was performed to determine CI variance among the breed groups and between previously reported clusters of breeds with similar DNA, which identifies common ancestry. Although CI differed significantly among some breed groups, neither the breed groupings nor the DNA clusters satisfactorily explained all the variance in CI. The results show that breed groupings and genetic clusters only partially explain CI differences. They also suggest that CI is on a continuum and that the definition of three categories of canine skull as dolichocephalic, mesocephalic, and brachycephalic may be overly arbitrary.     

驯鹿头髓解剖

运用大体解剖的方法对驯鹿头骨进行了形态学观察，并将其与双峰驼牛、马的头骨进行了比较。结果表明：驯鹿的梨骨特别发达。泪骨，额骨和鼻骨之间围成一个狭长的筛鼻甲窦（部）。下凳骨比牛、马、驼窄而长，下颌角钝圆。泪骨的形态较特殊，颜而形成纵形深窝，泪孔有两个，位于眶缘上，并有尖状的泪突分开，眶缘与颧骨交界处有一个深切迹，无泪囊窝。