Extracutaneous mast-cell tumor in the dog

Three neoplasms of extracutaneous mast-cell origin, arising from the nasopharynx, oral cavity, and hepatopancreatic lymph nodes respectively, were diagnosed in three dogs. The neoplasms had histologic features similar to those of cutaneous mast-cell tumors, but had limited metastasis mostly involving the regional lymph nodes. One dog had a perforating duodenal ulcer, suggesting that duodenal ulcers can occur with extracutaneous tumors as they do with some cutaneous mast-cell tumors in the dog.     

Lymph node staging of oral and maxillofacial neoplasms in 31 dogs and cats

A retrospective study was performed to report the histologic examination results of regional lymph nodes of dogs and cats with oral or maxillofacial neoplasms. Twenty-eight dogs and 3 cats were evaluated. Histologic examination results of standard and serial tissue sectioning of regional lymph nodes were recorded. When available, other clinical parameters including mandibular lymph node palpation, thoracic radiographs, and pre- and postoperative fine needle aspiration of lymph nodes were compared with the histologic results. Squamous cell carcinoma, fibrosarcoma, and melanoma were the most common neoplasms diagnosed in dogs. Squamous cell carcinoma and fibrosarcoma were diagnosed in cats. Of the palpably enlarged mandibular lymph nodes, 17.0% had metastatic disease histologically. Radiographically evident thoracic metastatic disease was present in 7.4% of cases. Preoperative cytologic evaluation of the mandibular lymph node based on fine needle aspiration concurred with the histologic results in 90.5% of lymph nodes examined. Postoperative cytologic evaluation of fine needle aspirates of regional lymph nodes concurred with the histologic results in 80.6% of lymph nodes examined. Only 54.5% of cases with metastatic disease to regional lymph nodes had metastasis that included the mandibular lymph node. Serial lymph node sectioning provided additional information or metastasis detection. Cytologic evaluation of the mandibular lymph node correlates positively with histology, however results may fail to indicate the presence of regional metastasis. Assessment of all regional lymph nodes in dogs and cats with oral or maxillofacial neoplasms will detect more metastatic disease than assessing the mandibular lymph node only.     

Vulvovaginectomy and perineal urethrostomy for neoplasms of the vulva and vagina

Vulvovaginectomy and perineal urethrostomy were performed in three dogs with extensive neoplasms of the vulva and vagina. One benign tumor (fibroleiomyoma) and two malignant tumors (transitional cell carcinoma and anaplastic spindle cell sarcoma) were diagnosed. Survival times were 9 weeks to 10 months. Urinary continence was preserved in all three dogs. The procedure may be curative for benign tumors or malignant tumors that have not yet metastasized; it is a palliative procedure for advanced malignancies.     

Vulvovaginectomy and Perineal Urethrostomy for Neoplasms of the Vulva and Vagina

Vulvovaginectomy and perineal urethrostomy were performed in three dogs with extensive neoplasms of the vulva and vagina. One benign tumor (fibroleiomyoma) and two malignant tumors (transitional cell carcinoma and anaplastic spindle cell sarcoma) were diagnosed. Survival times were 9 weeks to 10 months. Urinary continence was preserved in all three dogs. The procedure may be curative for benign tumors or malignant tumors that have not yet metastasized; it is a palliative procedure for advanced malignancies.     

Follicular stem cell carcinoma: histologic,immunohistochemical, ultrastructural,and clinical characterization in 30 dogs

Diagnostic records of 30 primary and one metastatic follicular stem cell carcinomas in 30 dogs were reviewed. Neoplastic cells had a clear cytoplasm and formed lobules and nests surrounded by a basement membrane. Trichoepitheliomatous and apocrine differentiations were noted in 22 of 30 (73%) and 21 of 30 (70%) primary tumors, respectively. Glycogen was present in 20 of 20 (100%) tumors tested, suggesting tricholemmal differentiation. Antibodies against AE1/AE3 cytokeratin, vimentin, and melanA/MART1 stained 29 of 30 (97%), 29 of 30 (97%), and 12 of 27 (44%) primary tumors, respectively. Small amounts of melanin were identified in 14 primary tumors, either on the hematoxylin and eosin-stained section (n = 6), or on the Fontana-stained section (n = 8 of 14). Ultrastructural features of neoplastic cells included cell junction complexes, swollen mitochondria, neuroendocrine-like granules, and intracytoplasmic non-membrane-bound accumulation of proteinaceous material. Features of this neoplasm are consistent with a follicular stem cell origin. Follow-up information was available for eight dogs. Metastases developed in the draining lymph node at the time of excision of the primary tumor (n = 1) or subsequently (n = 3).     

The Prognostic Significance of Angiogenesis in Canine Mammary Tumors

The purpose of the study was to determine if neovascularization, a measure of angiogenesis, is correlated with metastasis of mammary tumors in dogs. Forty-six paraffin-embedded tissue blocks of benign and malignant canine mammary tumors obtained from 42 clinical cases at the Iowa State University Veterinary Teaching Hospital were retrieved from the archives of the Department of Veterinary Pathology. Of the dogs with malignant tumors, cases with and without lymph node metastasis were chosen. Neovascularization was quantified by light microscopy on formalin-fixed, paraffin-embedded sections of canine mammary tumors using an avidin biotin immunoperoxidase assay for factor VIII-related antigen. Mean microvessel counts for each group were statistically evaluated using analysis of variance. The mean number of microvessels was highest in the malignant tumors of dogs with lymph node metastasis (44). This number was significantly different from the mean number of microvessels in the benign tumors (28; P = .03) and a trend occurred toward higher microvessel counts in malignant tumors with lymph node metastasis versus malignant tumors of dogs without metastasis (32; P = .1). No significant difference was found between the number of microvessels found in malignant tumors without metastasis versus benign tumors. The trend toward higher microvessel counts in mammary tumors that have metastasized supports the premise that angiogenesis may be an independent and significant prognostic indicator in dogs with malignant mammary tumors, as it is in women with breast cancer.     

Canine ovarian neoplasms: a clinicopathologic study of 71 cases, including histology of 12 granulosa cell tumors

In a retrospective study of 71 primary ovarian tumors in the dog, epithelial tumors (46%) were more common than sex cord stromal (34%) and germ cell tumors (20%). There were more adenocarcinomas (64%) than adenomas. Sex cord stromal tumors were equally divided into Sertoli-Leydig (12/24) and granulosa cell tumors (12/24). There were equal numbers (7/14) of dysgerminomas and teratomas among the germ cell tumors. Most teratomas (6/7) were malignant. Most granulosa cell tumors were solid; two were mostly cystic. Patterns included sheets of round and ovoid to spindle-shaped cells separated by thin, fibrovascular stroma; neoplastic cells formed rosettes or Call-Exner bodies. In some areas, neoplastic cells were in cords or columns and formed cyst-like structures. Four granulosa cell tumors were macrofollicular, having cysts lined with granulosa cells. Median ages of dogs with different ovarian neoplasms were similar; all were more than 10 years old, except the dogs with teratoma (mean age, 4 years). Most neoplasms were unilateral (84%), except the Sertoli-Leydig cell tumors, many of which were bilateral (36%). Size of ovarian neoplasms varied (2 cm3 to 15,000 cm3). Twenty-nine percent of neoplasms metastasized; adenocarcinomas (48%) and malignant teratomas (50%) had the highest rates, and distant metastasis was more common in malignant teratoma. Endometrial hyperplasia was in 67% of the dogs; it was most common in dogs with sex cord stromal tumors (95%). Uterine malignancy was not seen in dogs with granulosa cell tumors, although hyperplasia endometrium was in all dogs with this tumor. Cysts in the contralateral ovaries were most common in dogs with sex cord stromal tumors.     

Use of kit internal tandem duplications to establish mast cell tumor clonality in 2 dogs

Mast cell tumor (MCT) is one of the most common tumors of dogs. Some affected dogs develop multiple cutaneous tumors in various locations over months to years. In these cases, it is not clear whether the tumors have arisen de novo, or if each tumor represents a recurrence of the previously excised original tumor (ie, distant metastasis). We used the presence of an internal tandem duplication (ITD) in c-kit to demonstrate that in 2 dogs with recurrent cutaneous MCT that had developed over 1-2 years, each recurrent MCT tumor possessed an identical ITD when compared to the original MCT, indicating that the multiple tumors were clonal in origin. This study demonstrates that similar to the situation in humans, specific somatic mutations identified in oncogenes found in canine neoplasms can be used to provide evidence of tumor clonality.     

Sensitivity and specificity of methods of assessing the regional lymph nodes for evidence of metastasis in dogs and cats with solid tumors

OBJECTIVE: To determine sensitivity and specificity of physical examination, fine-needle aspiration, and needle core biopsy of the regional lymph nodes for evidence of metastasis in dogs and cats with solid tumors. DESIGN: Case series. ANIMALS: 37 dogs and 7 cats. PROCEDURE: Regional lymph nodes were evaluated by means of physical examination (palpation), fine-needle aspiration, and needle core biopsy. Results were compared with results of histologic examination of the entire lymph node, the current standard. RESULTS: Tumors included 18 sarcomas, 16 carcinomas, 7 mast cell tumors, and 3 other tumors. Carcinomas were more likely to have metastasized to the regional lymph node (7/16 animals) than were sarcomas (2/18). Sensitivity and specificity of physical examination were 60 and 72%, respectively. Sensitivity and specificity of cytologic examination of fine-needle aspirates were 100 and 96%, respectively. Sensitivity and specificity of histologic examination of needle core biopsy specimens were 64 and 96%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that fine-needle aspiration may be a sensitive and specific method of evaluating the regional lymph nodes in dogs and cats with solid tumors, because results correlated well with results of histologic examination of the entire lymph node. Physical examination alone was not a reliable method and should not be used to decide whether to aspirate or biopsy the regional lymph nodes.     

犬常见肿瘤流行病学调查及组织病理学诊断

为探讨犬常见肿瘤的发病规律，试验收集哈尔滨地区2016-2017年宠物医院部分犬肿瘤病例71例，采用组织病理学方法对犬肿瘤进行病理学诊断，并对患病动物的品种、性别、年龄、发生部位和饮食情况与肿瘤发生关系进行统计分析。结果显示，71例确诊肿瘤病例中，恶性肿瘤28例，包括鳞状上皮细胞癌3例，基底细胞癌5例，乳腺癌14例，淋巴瘤2例，肾母细胞瘤、精原细胞癌、生殖细胞癌、侵袭性血管黏液瘤各1例；良性肿瘤43例，包括良性乳腺肿瘤15例，纤维瘤10例，平滑肌瘤5例，乳头状瘤和精原细胞瘤各3例，造釉细胞瘤、耵聍腺瘤、脂肪瘤、结节样增生、性索间质细胞瘤、颗粒细胞瘤、肛周腺瘤各1例。上述病例中，乳腺和皮肤是犬肿瘤的高发部位，分别占全部患犬的40.8%和34.0%；患病犬年龄1~16岁不等，平均发病年龄为9.1岁，7岁以后是肿瘤的高发期，中老年犬仍为主要发病群体，但低龄犬发病数量上升；各品种犬均可发生肿瘤，其中杂种犬发病率最高，其次是贵宾犬和京巴犬，且主要为乳腺肿瘤；饮食习惯主要以剩饭剩菜类和肉拌饭类为主，分别占患犬总数的39%和30%；部分肿瘤类型与犬的性别、是否绝育有关，如乳腺肿瘤多发生于未绝育的老年母犬。本研究结果为犬肿瘤的流行病学及诊断提供了参考依据，对犬肿瘤的预防和诊断有一定的借鉴意义。     

Gross, histologic, cytochemical, and immunocytochemical study of medullary thyroid carcinoma in sixteen dogs

The gross, histomorphologic, cytochemical, and immunocytochemical findings in 16 dogs with medullary thyroid carcinoma were evaluated. Grossly, the neoplasms were encapsulated, firm, lobulated, and grey-white to tan. The typical histologic pattern was groups or sheets of round to polygonal cells with fibrovascular stroma, which was thickened and hyalinized in places. Variants of clear cell (two dogs), giant cell (one dog), and oxyphil cell (one dog) types were also seen. In all 16 dogs, Grimelius-stained sections of the neoplasms revealed intracytoplasmic silver granules; ten tumors contained amyloid and four contained mucin. Immunohistochemically, the neoplasms reacted to AE1/AE3 (n = 13), S-100 protein (n = 5), neuron specific enolase (n = 14), synaptophysin (n = 11), calcitonin (n = 16), somatostatin (n = 4), gastrin (n = 7), and serotonin (n = 6). Only one neoplasm was positive for vimentin. None of the neoplasms reacted to antibodies for neurofilaments, thyroglobulin, insulin, glucagon, or adrenocorticotrophic hormone. Eleven neoplasms contained multiple (two to four) peptides, in various combinations. It was concluded that in dogs, gross and histologic features can be used to distinguish medullary thyroid carcinoma from other thyroid malignancies. Cytochemical and immunocytochemical studies with neuron specific enolase, synaptophysin, and calcitonin can be used to establish the diagnosis of medullary thyroid carcinoma in dogs.     

Clinical and pathologic features of thyroid tumors in 26 dogs

Thyroid tumors were diagnosed in 26 dogs between 1977 and 1984. A total of 23 of the 26 tumors were carcinomas, and 3, detected as incidental findings at necropsy, were adenomas. The median patient age was 9.5 years. Dogs of the Beagle breed were affected most commonly (5 dogs). The most common physical abnormalities in carcinoma patients were cervical swelling, dyspnea, and coughing. A total of 25 of 26 dogs were clinically euthyroid. Aspiration cytology provided diagnostic information in 8 of 17 cases. In dogs with thyroid carcinoma, a cervical soft tissue lesion was identified consistently by use of radiography and scintigraphy with sodium pertechnetate. Pulmonary metastases were detected radiographically in 8 of 21 dogs with thyroid carcinoma. Thoracic nuclear imaging confirmed the radiographic findings in 11 of 14 dogs. Surgical excision of the thyroid mass was the primary treatment for 17 dogs with carcinoma. Eight dogs died within 2 years (median, 7 months) of surgery because of primary tumor regrowth or metastases. Four dogs were alive at a range of 3 to 48 months after surgery, and 4 dogs died from unrelated causes. Necropsy of 7 dogs with thyroid carcinoma revealed neoplastic infiltration of the cervical blood vessels and pulmonary metastases in each dog. The most common histologic patterns of thyroid carcinoma were solid or compact cellular (11 dogs) and mixed solid-follicular tumors (8 dogs). Dogs with a solid carcinoma had a median survival time of 10.5 months (6 dogs), and dogs with a mixed solid-follicular tumor had a median survival time of 8 months (3 dogs).     

Radiation therapy for incompletely excised grade II canine mast cell tumors

Forty-five dogs with incompletely excised grade II mast cell tumors were treated with radiation using a cobalt 60 teletherapy unit (15 fractions of 3.2 Gy for a total of 48 Gy). Twenty-four of the dogs underwent prophylactic regional lymph node irradiation. Three (6.7%) dogs had tumor recurrence, two (4.4%) dogs developed metastasis, and 14 (31%) dogs developed a second cutaneous mast cell tumor. No difference in overall survival rate was observed between the dogs receiving and not receiving prophylactic irradiation of the regional lymph node.     

Cytopathology of canine lymphomas (100 cases)

Malignant lymphoma is one of the most common malignant tumours occurring in dogs. Fine needle aspiration biopsy (FNAB) is an excellent, specific diagnostic procedure used to assess pathological processes in lymph nodes. The aim of the present study was to conduct a cytopathological analysis of lymphoma in dogs and to analyse some epidemic aspects of occurrence of lymphoma in 100 dogs using Giemsa stained slides. Samples were obtained by fine needle aspiration biopsy, fine needle non-aspiration biopsy, lymph node impression smears and by examination of body cavity effusions. The determination of the type and subtype of tumour was made on the basis of the updated Kiel classification adopted for dogs. Based on cytopathological analysis, the lymphoma was diagnosed in 100 dogs: 44 were female and 56 male. The animals' age ranged from 1.5 year to 15 years (median: 7.5 years), the animals were of different breeds (72% of all dogs belonged to 28 different breeds) and crossbreeds (28%). In 29% of dogs the regional or general lymphadenomegaly was the only clinical sign observed, in remaining cases (71%) at least one abnormality connected to lymphoma was found. Among all diagnosed lymphomas, high-grade lymphomas were more prevalent (86% of all cases) than low-grade lymphomas (14% of all cases). The possibility of boxers having a predisposition to T cell lymphoma development could be also suspected.     

Systemic Mastocytosis in 16 Dogs

The clinical and pathologic features of systemic mastocytosis in 16 dogs are reported. There was no apparent breed or sex predilection, and the median age at presentation was 9.5 years. In 14 of 16 cases there was a primary cutaneous mast cell tumor (MCT). When cutaneous tumor location was compared with previous reports, there was no association between location and systemic dissemination. The most common presenting signs associated with the cutaneous tumor were regional dissemination, edema, ulceration, and abscessation. They were present in 12 dogs (69%). Signs of systemic illness, including anorexia, vomiting, and diarrhea, were seen in eight dogs (50%). Other than the cutaneous tumors, the most consistent physical and radiographic abnormalities included lymphadenopathy, splenomegaly, and hepatomegaly. Eosinophilia and basophilia were seen in two and five dogs, respectively. Six dogs had increased numbers of mast cells in peripheral blood or buffy coat smears. Five of the nine dogs evaluated had increased numbers of mast cells in bone marrow aspirates. Bone marrow aspiration was superior to both peripheral blood and buffy coat smears in predicting mastocytosis. Coagulation abnormalities were seen in three of five dogs tested. Using a conventional histomorphologic grading system, 10 of 13 (77%) tumors were classified as Grade III or undifferentiated and were overrepresented when compared with previous reports of cutaneous MCTs. Eighty-eight percent of the dogs either died or were euthanatized because of their tumors. Organs commonly involved at necropsy included lymph nodes, spleen, liver, and bone marrow; four dogs had gastroduodenal ulcers.     

Correlation of DNA ploidy to tumor histologic grade, clinical variables, and survival in dogs with mast cell tumors.

By using flow cytometry, a retrospective analysis of the DNA content of 40 primary canine mast cell tumors and seven lymph nodes that contained metastatic mast cell tumor from 44 dogs of various breed, sex, and age was performed on formalin-fixed, paraffin-embedded samples of the tumors and nodes. These samples were chosen according to the following criteria: samples contained sufficient well-preserved tumor tissue in the paraffin block for processing, sufficient patient history data were available, clean and homogeneous cell suspensions were obtained after processing, and interpretable DNA histograms were produced on analysis. The ploidy data obtained were compared with the histopathologic grade, the anatomical site of occurrence, the clinical stage of the tumors, and the survival of the dogs. Over 70% (29/40) of the mast cell tumors were diploid. Three metastatic mast cell tumors in lymph nodes had the same ploidy status as their corresponding primary tumors. In five dogs, mast cell tumors from multiple sites in each dog displayed similar ploidy status. Of 26 dogs evaluated for survival times, 69% (18/26) had diploid tumors and 31% (8/26) had aneuploid tumors. When numbers of diploid versus aneuploid tumors were compared, no significant difference was found between any two grades, clinical stages, or anatomic sites. A significant difference (P = 0.02) was found, however, between aneuploid and diploid tumors when comparing Stage I and non-Stage I disease. The Kaplan-Meier survival plot indicated a tendency towards an increased survival within the first year in dogs with diploid versus aneuploid tumors (P = 0.06).     

Histologic features of hair follicle neoplasms and cysts in dogs and cats: a diagnostic guide

Hair follicle neoplasms occur in many different species, including humans. In domestic animals, they are most common in dogs. Most hair follicle tumors are benign, but malignant neoplasms can also occur. To diagnose hair follicle neoplasms, a thorough knowledge of follicular anatomy is important, given that follicular tumors are classified according to the differentiation pattern seen in the corresponding part of the normal hair follicle. This review focuses on the key diagnostic features of hair follicle tumors and follicular cysts in dogs and cats.     

Immunohistochemical studies on cytokeratin 8 and 18 expressions in canine cutaneous adnexus and their tumors

The expressions of cytokeratin 8 and 18 (CK8 and CK18) in the normal canine skin (2 cases) and cutaneous adnexal tumors (127 cases) were investigated immunohistochemically. In the normal skin, co-expression of CK8/18 was found in the glandular epithelium of apocrine sweat glands, and single CK8-immunoreactivity was detected occasionally in the external root sheath at the isthmus and suprabulbar regions of the hair follicles. Neoplastic glandular epithelial cells in all apocrine gland tumors (21/21 cases, 100%) had co-expression of CK8/18. In trichoblastomas (27/28 cases, 96%), most neoplastic cells were diffusely positive for CK8, but those were negative for CK18. Single CK8-expression was also observed in basaloid neoplastic cells in several cases of trichoepitheliomas (7/19 cases, 37%) and pilomatricoma (1/7 cases, 14%). In several cases of trichoblastomas (4/28 cases, 14%) and trichoepitheliomas (2/19 cases, 11%), tumor cells forming glandular structures had co-expression of CK8/18. There were no positive reactions for both CK8 and 18 in infundibular keratinizing acanthomas, and sebaceous and hepatoid gland tumors. The present findings indicate that co-expression of CK8/18 is a specific feature of apocrine sweat glands and single CK8-expression represents the natures of external root sheath or pluripotential stem cells. Thus, the combination of CK8- and 18-immunostainings may have the utility to confirm the directions of differentiation in canine cutaneous adnexal tumors providing a reliable hallmark for histopathological diagnoses.     

Pheochromocytoma in 50 Dogs

Fifty dogs with pheochromocytoma were identified in a retrospective study of a 9-year period. For 24 of 50 dogs (48%), the tumor was an incidental finding during necropsy or surgery. Presenting signs were referrable to the nervous system in 7 of the 26 symptomatic dogs (27%); were referrable to the cardiopulmonary system in 7 of 26 dogs (27%); or were nonspecific, reflecting general systemic disease, in 17 of 26 dogs (65%). Abnormal clinical findings were highly varied but were also generally referrable to the cardiopulmonary and nervous systems. Six of 7 dogs (86%) evaluated were hypertensive (systolic range, 164 to 325 mm Hg; diastolic range, 110 to 198 mm Hg). Serum biochemical findings were nonspecific, although 11 of 39 dogs (28%) were hypercholesterolemia Abdominal fluid samples were analyzed in 6 dogs; 3 were nondiagnostic, and 3 were interpreted as lymphosarcoma. The imaging studies that were of most value included abdominal radiographs (mass identified in 9 of 16 dogs [56%]), caudal vena caval angiography (tumor thrombus correctly diagnosed in 4 of 7 dogs [57%]), and abdominal ultrasonography (mass seen in 5 of 6 dogs [83%] and tumor thrombus seen in 3 of 5 dogs [60%]). Local tumor invasion was present in 26 of 50 dogs (52%), regional lymph node mestatases in 6 of 50 dogs (12%), and distant metastases in 12 of 50 dogs (24%). Cause of death was tumor-related in 19 of 50 dogs (38%) and non-tumor related in 28 of 50 dogs (54%).     

Retrospective outcome evaluation for dogs with surgically excised,solitary Kiupel high‐grade,cutaneous mast cell tumours

Published outcomes for dogs with specifically high‐grade mast cell tumours (MCTs), controlled for clinical stage, are few. Clinical outcomes for 49 dogs with Kiupel high‐grade, clinical stage I, cutaneous MCTs were evaluated. Median survival time (MST) was 1046 days; 1 and 2‐year survival rates were 79.3% and 72.9%, respectively. At study end 24 dogs had died, 23 dogs were alive (median follow‐up 980 days) and 2 dogs were lost to follow‐up. Death was considered MCT‐related in 14 of 20 dogs with a known cause of death. Local tumour recurrence developed in nine dogs (18.4%); regional lymph node metastasis occurred in six dogs (12.2%); and a new MCT developed in 15 dogs (30.1%). Tumour location, histologic margin size and use of chemotherapy did not affect MST; increasing mitotic count (P = .001) and increasing tumour diameter (P = .024) were independently negatively prognostic. Six dogs that developed lymph node metastasis after surgery had worse MST (451 days) than 42 dogs that did not develop metastasis (1645 days); (P < .001). Our study suggests that dogs with local surgical control of clinical stage I histologically high Kiupel grade cutaneous MCT may have a long survival time; especially those with smaller tumours and a lower mitotic count. Our results suggest that evaluation of staging information and mitotic count may be equally helpful as histologic grading when making a prognosis; and highlight the importance of not relying on histologic grade alone when predicting survival for dogs with MCT.