Malignant mast cell tumor in an African hedgehog (Atelerix albiventris)

Multiple Distinct Neoplasms in a North African Hedgehog (Atelerix algirus)

This paper describes the clinical and pathological features of 4 different tumors, located in the integumentary, digestive, and endocrine systems, presenting in a North African hedgehog (Atelerix algirus). A 3.5-year-old female hedgehog was presented with a cutaneous mass on the right flank. The lesion consisted of a well-differentiated dermal mast cell tumor with no recurrence and metastasis after complete surgical excision. Six months later, the hedgehog developed a mass in the left lower jaw, lethargy, anorexia, and progressive weight loss. Clinical and radiographic evaluations revealed swelling, ulceration, displacement, and destruction of subjacent bone tissue, and the animal died 1 month after the onset of clinical signs. At necropsy, 2 neoplasms in the oral cavity (squamous cell carcinoma and histiocytic sarcoma) and multiple myelolipomas in the adrenal glands were detected. Metastasis of the oral squamous cell carcinoma was observed in the lungs. Although neoplasms are frequent in this species, and more than 1 type of tumor in a single individual has been occasionally reported, this is the first description of both myelolipoma and multiple concurrent neoplasms involving various organs and different cellular origins in a hedgehog.

Pathological Findings in African Pygmy Hedgehogs Admitted into a Portuguese Rehabilitation Center

Most of the pathologies that affect hedgehogs are diagnosed postmortem; thus, it is essential to share knowledge between clinicians and pathologists in order to recognize predispositions to diseases and to establish adequate diagnostic and therapeutic plans. This study aimed to describe the most relevant postmortem pathological conditions in a group of six rescued African pygmy hedgehogs, performed over a period of four months. Hedgehogs were submitted to necropsy examinations and subsequent histopathological analyses. Microscopically, all the studied hedgehogs revealed alterations in one or more organ systems. Although a significant and diverse number of pathological conditions were obtained, this study focused on less common or more relevant pathologies found in African pygmy hedgehogs-namely, wobbly hedgehog syndrome, squamous cell carcinoma and mast cell tumors. Furthermore, this study constitutes the first report of Mycobacterium spp. in hedgehogs in Portugal, the second report of follicular thyroid carcinoma in an African pygmy hedgehog, the description of a lipoid pneumonia for the first time in this species and a lung adenocarcinoma-a pathology rarely reported in African pygmy hedgehogs.

Disseminated Haemophagocytic Histiocytic Sarcoma in an African Pygmy Hedgehog (Atelerix albiventris)

A 3-year-old intact male African pygmy hedgehog (Atelerix albiventris) was found dead shortly after clinical onset of screaming, aerophagia and lethargy. On gross examination, the spleen was dark red and friable, and the liver was markedly enlarged with a prominent lobular pattern and multiple white nodules. Histopathological examination of liver and spleen revealed dense infiltrates of highly pleomorphic neoplastic, round to polyhedral cells with overt erythrophagocytosis. Similar neoplastic cells were found in the sinuses of the abdominal lymph nodes and in blood vessels in the heart, lung, brain and kidneys. Immunolabelling for CD204 confirmed the histiocytic origin of the neoplastic cells. To our knowledge, this is the first report of a disseminated haemophagocytic histiocytic sarcoma in a hedgehog.

Geriatric Hedgehogs

African hedgehogs are susceptible to aging changes like those of other small exotic mammals. Common conditions of the geriatric hedgehog include heart disease, chronic renal disease, and dental/periodontal disease. Hedgehogs are unique in that they have an unusually short life span and a propensity for neoplasia. These 2 factors make it especially common for exotic animal practitioners to encounter geriatric hedgehogs affected by one of the many conditions outlined in this article.

Systemic mastocytosis and probable mast cell leukaemia in a koala (Phascolarctos cinereus)

BACKGROUND

To the authors' knowledge, this is the first report of mast cell neoplasia in a koala (Phascolarctos cinereus).

CASE REPORT

An adult female koala was presented for rapidly deteriorating health and death of a pouch young. Significant weight loss was apparent despite supplemental feeding; the abdomen was distended; and the koala was weak and mentally depressed. Haematology revealed a significant mastocytosis with a concurrent population of atypical mononuclear cells. The koala was euthanised and tissues were collected for histology. Bone marrow, lymph node, lung, stomach and spleen exhibited significant infiltration by mast cells. Atypical round cells consistent with those identified in the peripheral blood were also identified in the marrow. A diagnosis of systemic mastocytosis and probable mast cell leukaemia was made. Immunocytochemical and immunohistochemical staining was not able to further characterise the atypical cell population, and the mast cells exhibited only weak staining with CD117.

CONCLUSION

The histological diagnosis, in this case, was systemic mastocytosis and myeloproliferative disease of uncertain origin. There was a dominant population of mast cells in the peripheral blood and marrow, and a population of circulating atypical mononuclear cells, appearing similar to mast cell leukaemia-acute myeloid leukaemia in humans.

Comparative aspects of mast cell neoplasia in animals and the role of KIT in prognosis and treatment

Mast cell neoplasia clinical presentation and biological behaviour vary considerably across mammalian species, ranging from a solitary benign mass to an aggressive systemic malignancy. Mutations in the KIT Proto‐Oncogene Receptor Tyrosine Kinase (KIT) gene are common molecular abnormalities involved in mast cell tumorigenesis. KIT mutations often occur in dog, cat and human neoplastic mast cells and result in altered Kit protein structure and function. In dogs, certain KIT mutations are associated with more malignant and lethal disease. In contrast, KIT mutations in feline and human mast cell neoplasms are not correlated with prognosis, but are of value in diagnosis and treatment planning in humans. KIT genetic abnormalities have not been well investigated in other species, although aberrant cytoplasmic Kit protein staining detected in neoplasms of the ferret, horse and cow resembles aberrant Kit staining patterns detected in neoplastic mast cells of dogs, cats and humans. Mutations within KIT are classified as either regulatory‐type or enzymatic pocket‐type mutations according to their location within the KIT Proto‐Oncogene. Mutations within the enzymatic pocket domain confer tumour resistance to tyrosine kinase inhibitors (TKIs). Hence, knowledge of tumour KIT mutation status adds valuable information for optimizing patient treatment strategies. The use of TKIs in combination with conventional chemotherapeutics has opened a new treatment avenue for patients unresponsive to existing drugs. This review highlights the similarities and differences of mast cell neoplasia in mammals with a special focus on the involvement of KIT in the canine and feline forms in comparison to human mast cell neoplasia.

Metastasis in the wild: investigating metastasis in non-laboratory animals

Humans are not the only species to spontaneously develop metastatic cancer as cases of metastasis have been reported in a wide range of animals, including dinosaurs. Mouse models have been an invaluable tool in experimental and clinical metastasis research, with the use of genetically-engineered mouse models that spontaneously develop metastasis or ectopic/orthotopic transplantation of tumour cells to wildtype or immunodeficient mice being responsible for many key advances in our understanding of metastasis. However, are there other species that can also be relevant models? Similarities to humans in terms of environmental exposures, life-span, genetics, histopathology and available therapeutics are all factors that can be considered when looking at species other than the laboratory mouse. This review will explore the occurrence of metastasis in multiple species from a variety of domestic, captive and free-living veterinary cases to assist in identifying potential alternative experimental and clinical research models relevant to humans.

From humans to hydra: patterns of cancer across the tree of life

Cancer is a disease of multicellularity; it originates when cells become dysregulated due to mutations and grow out of control, invading other tissues and provoking discomfort, disability, and eventually death. Human life expectancy has greatly increased in the last two centuries, and consequently so has the incidence of cancer. However, how cancer patterns in humans compare to those of other species remains largely unknown. In this review, we search for clues about cancer and its evolutionary underpinnings across the tree of life. We discuss data from a wide range of species, drawing comparisons with humans when adequate, and interpret our findings from an evolutionary perspective. We conclude that certain cancers are uniquely common in humans, such as lung, prostate, and testicular cancer; while others are common across many species. Lymphomas appear in almost every animal analysed, including in young animals, which may be related to pathogens imposing selection on the immune system. Cancers unique to humans may be due to our modern environment or may be evolutionary accidents: random events in the evolution of our species. Finally, we find that cancer‐resistant animals such as whales and mole‐rats have evolved cellular mechanisms that help them avoid neoplasia, and we argue that there are multiple natural routes to cancer resistance.

Spontaneous multicentric soft tissue sarcoma in a captive African pygmy hedgehog (Atelerix albiventris): case report and literature review

This report describes the clinical, macroscopic, histopathological and immunohistochemical features of a spontaneous multicentric extraskeletal sarcoma in an adult male African hedgehog (Atelerix albiventris). It also provides a succinct up-to-date review on neoplasia in this species. On autopsy examination, main gross findings included a moderately demarcated cranial mass and a multilobulated, caudal intra-abdominal mass. The cranial mass had perforated the underlying temporal and occipital bones and had extended into the cranial vault and was compressing the surface of the cerebellum and cerebrum. Histologic, histochemical and immunohistochemical analyses supported a diagnosis of multicentric poorly differentiated spindle cell sarcoma with fibrosarcomatous, storiform and myxoid foci. The high incidence of neoplasia and cross similarities renders the African hedgehog a suitable species for comparative pathology studies.

Pulmonary Mast Cell Tumor and Possible Paraganglioma in a Free-ranging Pacific Walrus ( Odobenus rosmarus divergens), Barrow, Alaska, USA

We describe a pulmonary mast cell tumor in a subsistence-harvested free-ranging Pacific walrus (Odobenus rosmarus divergens). Neoplastic cells effacing a focal area of pulmonary parenchyma were characterized by rare metachromatic granules and positive staining for C-kit. We also report co-occurrence of a peribronchial mass with a morphologic and immunohistochemical profile compatible with paraganglioma.

Surgical resection of peripheral odontogenic fibromas in African pygmy hedgehog (Atelerix albiventris): a case study

Background

Neoplastic lesions of the mammary gland, lymph nodes, or oral cavity in African pygmy hedgehogs (Atelerix albiventris) are common in captive animals. Chemotherapy and radiotherapy protocols have not yet been established for the African pygmy hedgehog. Thus, surgical resection is the current treatment of choice in this species.

Case presentation

A 5-year-old male African pygmy hedgehog showed multiple erythematous, round small tumors located in the oral cavity, on both sides of maxilla. The treatment of choice was surgical resection of tumors using a surgical knife under general anesthesia. Excised neoplastic lesions were diagnosed as peripheral odontogenic fibroma by histopathology. Six months after surgery relapse of tumors in the oral cavity was not observed.

Conclusions

The treatment adopted in this case report is safe for the patient and provides the best solution for mild proliferative lesions of the oral cavity. To our knowledge this is the first report of surgical resection of oral tumors (peripheral odontogenic fibroma) in the African pygmy hedgehog.

Emergency and critical care procedures in sugar gliders (Petaurus breviceps), African hedgehogs (Atelerix albiventris), and prairie dogs (Cynomys spp)

Less common exotic pet mammals are gaining in popularity. The Australian Sugar Glider, African Hedgehog, and prairie dog are seen regularly in exotic animal practices. They are subject to the same types of medical emergencies as more traditional pets, with the unfortunate addition of all too common underlying nutritional and husbandry-related disorders. Emergency stabilization and critical care are important first steps before collection of diagnostic test samples and administration of definitive medical care.

Spontaneous cutaneous mast cell tumor with lymph node metastasis in a Richardson's ground squirrel (Spermophilus richardsonii)

A 4-year-old female Richardson's ground squirrel (Spermophilus richardsonii) presented with multicentric nodules arising from the skin of the middle of the tail and lumbosacral regions. Histologically, the nodules were composed of a proliferation of spindloid to pleomorphic cells that sometimes formed sheets and fascicular to storiform patterns. Diffuse infiltration of eosinophils was also noted. The results of immunohistochemistry indicated positive labeling for vimentin, mast cell tryptase, c-kit, and Ki-67. Toluidine blue stain revealed fine, metachromatic, cytoplasmic granules. The histologic diagnosis was mast cell tumor. The neoplasm recurred and metastasized to the right lumbar lymph node 1 month later.

Squamous cell carcinoma and consequent otitis in a Long-eared Hedgehog (Hemiechinus auritus)--case report

The authors describe a squamous cell carcinoma arising from the ear canal of a Long-eared Hedgehog (Hemiechinus auritus). No metastasis could be identified elsewhere in the animal. Due to the irritation caused by the tumorous proliferation the animal constantly scratched the affected area, which led to secondary bacterial infection of the middle ear accompanied by the stagnation of an increased volume of local secretions. Using routine haematoxylin and eosin and immunohistochemical staining techniques, the tumour was identified as a squamous cell carcinoma. This work constitutes the first description of such a tumour in a Long-eared Hedgehog.

Morphological and Immunohistochemical Characterization of Spontaneous Mammary Tumours in European Hedgehogs ( Erinaceus europaeus )

Mammary tumour samples (11 surgical and five post-mortem) from 16 adult European hedgehogs submitted between 1980 and 2004 were examined. Histologically, the tumours were classified as simple tubulo-papillary carcinomas with local invasive growth. In six cases, tumour cell emboli were present in blood vessels or lymphatic vessels, or both. However, metastasis to regional lymph nodes was found only in one hedgehog. Malignant neoplastic epithelial cells were immunolabelled by antibodies specific for various cytokeratins (CKs), including CK1-8, 10, 13-16, 19 and 20. CK expression did not differ from that in normal mammary gland tissue. CK20 was expressed in the mammary tissue of hedgehogs, in contrast to that of dogs and cats; CK7 immunolabelling, however, which commonly occurs in mammary epithelial cells, was negative. CK20 expression, together with the lack of CK7 as determined by a protein-specific antibody, represented an important difference from the CK profile shown by mammary epithelial cells of other mammalian species, including the dog and cat.

Spontaneous tumors of small mammals

The most common tumor of guinea pigs is bronchogenic papillary adenoma; of hedgehogs is mammary gland adenocarcinoma; of hamsters is adrenal cortical adenoma; of gerbils is ovarian granulosa cell and theca cell tumors; of mice is pulmonary carcinoma; and of rats is mammary fibroadenoma. A relatively low incidence of tumors is described for chinchillas and hamsters, whereas the incidence of tumors is high for gerbils, hedgehogs, mice, and rats. Limited literature regarding neoplasia exists for prairie dogs, sugar gliders, and chinchillas.

Principles of wound management of small mammals: hedgehogs, prairie dogs, and sugar gliders

The management of wounds is a common scenario for the exotic animal practitioner. When presented with such cases, the practitioner must first adhere to the firmly established principles of wound healing, and then modify available treatment modalities to fit the needs of the species at hand. Practicing wound management on exotic patients can be challenging due to their small size, unusual anatomy, difficult behaviors, and tendency for developing secondary stress-related health problems. A review of the stages of wound healing as well as traditional wound management techniques is provided here. This review is followed by a summary of typical wounds encountered in hedgehogs, prairie dogs, and sugar gliders, as well anatomic, physiologic, and behavioral characteristics that should be taken into consideration when managing wounds on such species.

Soft tissue sarcomas in the African hedgehog (Atelerix albiventris): microscopic and immunohistologic study of three cases

Three soft tissue tumors from 2 female hedgehogs were examined microscopically and immunohistochemically. Two tumors involved haired skin and the third one was vaginal. Microscopically, the cutaneous tumors had features of malignant peripheral nerve sheath tumor (MPNST), whereas the vaginal tumor was classified only as a spindle cell sarcoma. Immunohistochemically, all 3 tumors were strongly positive for vimentin and strongly to moderately positive for CD10 and neuron-specific enolase but did not stain with antibody to S100 protein, an antigen typically present in human MPNST The cutaneous tumor from hedgehog no. 1 was examined ultrastructurally and the neoplastic cells resembled fibroblasts. Hedgehog no. 1 was euthanized at the time of the biopsy. The outcome of the other hedgehog was unknown.

Spontaneous tumours in captive African hedgehogs (Atelerix albiventris): a retrospective study

Forty tumours were diagnosed in 35 (53%) of 66 captive African hedgehogs documented at Northwest ZooPath (NZP) between 1994 and 1999. Three hedgehogs had more than one type of tumour and the remaining 32 had a single type. Of the 35 hedgehogs with tumours, 14 were female, 11 were male, and 10 were of unknown gender; 21 were from zoological parks and 14 were privately owned. Twenty of the hedgehogs with tumours were adult (>1 year old) with a median age of 3.5 years (range 2-5.5 years); 15, of unreported age, were classified as adult. Thirty-four (85%) of the 40 tumours were classified as malignant and six (15%) as benign. The integumentary, haemolymphatic, digestive and endocrine systems were common sites for tumours. The most common tumours were mammary gland adenocarcinoma, lympho-sarcoma and oral squamous cell carcinoma.

Clinical pathology and sample collection of exotic small mammals

The clinical pathology of some of the less common and newly emerging small mammal species is detailed in this article. The species covered here include the chinchilla, prairie dog, African hedgehog, and sugar glider. Venipuncture sites and sampling techniques are discussed in general and for each species. Detailed information on the hematology and serum biochemistry values of these animals is presented in numerous tables. Specific information is also provided for urinalysis, fecal analysis, dermatologic sampling, and cytology.