Canine Carcinosarcomas in the Head

Pathological and Immunohistochemical Microscopy of Natural Cases of Canine and Feline Neoplastic Mammary Lesions

Mammary cancer is the second most common tumor worldwide. Small animal mammary neoplasms provide an outstanding model to study cancer in humans, as tumors in both share a similar environment, histopathologic features, and biological behavior. This study aims to investigate the percentage and microscopy of breast tumors in affected dogs and cats; its relationship to breed, age, and sex; and the immunohistochemical expression of estrogen receptor (ER), progesterone receptor (PR), Ki-67, and cytokeratin 8. Twenty-four females (12 dogs and 12 cats) and one male were examined from February 2018 to February 2020. The highest percentage of mammary neoplasia from the highest to the lowest manifested as tubular carcinoma, leiomyosarcoma, fibroadenoma, and cystic papillary carcinoma. The current study reported the second micropapillary invasive carcinoma in a male cat and the third lipid-rich carcinoma in a female cat. Although tubular carcinoma was the most common mammary neoplasm in cats, leiomyosarcoma was the most common in dogs. The immunohistochemical staining revealed diffuse and intense cytoplasmic immunoreactivity for cytokeratin 8 in lipid-rich carcinomas. However, moderate expression of ER in benign tumors and slight to moderate ER expression in malignant mammary lesions were reported. On the contrary, there was a negative PR expression in benign lesion. It could be concluded that a close relationship between ER expression and nuclear antigen Ki-67 was found.

Bilateral Thyroid Carcinosarcoma in a Cat

A neutered female domestic shorthaired cat was presented for a rapidly growing left cervical mass and a 6-month history of primary hyperthyroidism. Cytological examination of the mass was consistent with a sarcoma. Due to poor clinical response the cat was humanely destroyed and a post-mortem examination was performed. This revealed a markedly enlarged, irregularly shaped left thyroid gland with signs of infiltration of the trachea. The contralateral (right) thyroid was also moderately enlarged and irregularly shaped. Histopathological examination of the cervical masses indicated bilateral thyroid carcinosarcomas, evidenced by positive immunohistochemical labelling for vimentin, pan-cytokeratin and thyroid transcription factor-1 of the appropriate cell populations. The cat also had a concurrent pulmonary adenocarcinoma (papillary-lepidic type), unrelated to the thyroid neoplasm. Thyroid carcinosarcoma is an uncommonly recorded canine and human neoplasm and this is the first case of this entity to be reported in a cat.

A Comparative Review of Mixed Mammary Tumors in Mammals

Mixed tumors are characterized by the histological identification of two or more cell types. Commonly, a mixture of epithelial and myoepithelial cells is included in abundant stroma, which can consist of myxoid, chondroid or bony matrices. Spontaneously arising mixed tumors are rare lesions in the human breast but are common in human salivary glands and canine mammary glands. Subtle histopathological characteristics and overlapping attributes of malignant lesions with other benign lesions can lead to a diagnostic challenge. Mixed tumors can present as benign or malignant. While malignant mixed tumors are quite rare in the human breast they have a poor prognosis. Benign mixed mammary tumors occur more frequently in female dogs than in humans and are usually associated with a good prognosis. This review will provide a comprehensive overview of mixed mammary tumors, across various mammalian species.

Uterine carcinosarcoma (malignant mixed Müllerian tumor): case report in a goat and literature review

Carcinosarcomas are biphasic malignant tumors composed of 2 distinct neoplastic cell populations, epithelial cells and mesenchymal cells. A 13-y-old, female, mixed-breed goat was presented with a 1-wk history of anuria and lethargy. Transabdominal ultrasonography showed an irregular and heterogeneous structure in the region of the bladder and uterus and changes in the echogenicity of both kidneys. Given the poor prognosis, euthanasia was elected. Autopsy revealed a large mass within the uterine cervix and confirmed the changes in the urinary tract. Histopathology and immunohistochemistry revealed a mixed, anti-cytokeratin AE1/AE3-positive epithelial, and vimentin-positive mesenchymal neoplasm consistent with a homologous carcinosarcoma, also called malignant mixed Müllerian tumor, with areas of double-labeling. We highlight the complexity of the diagnosis of uterine neoplasms in domestic animals and in goats in particular.

Carcinosarcoma of the biliary system in a cat

A 12-year-old, mixed-breed domestic cat was diagnosed with a multicystic hepatic mass via ultrasonographic examination and computer tomography scan. The tumor associated with the left medial liver lobe, and connected by a thin stalk to the hilar region, was surgically removed. The mass was firm, encapsulated, mottled white to red black, multinodular, and cystic. Histologic diagnosis was carcinosarcoma supported by positive immunohistochemistry for cytokeratins and vimentin of atypical neoplastic cell populations. On the basis of morphology, the origin was considered to be in the biliary tract. Biliary carcinosarcoma is a rare neoplasm that occurs in people. The epidemiology and risk factors have not yet been determined, and the prognosis is poor except for cases in which curative resection is performed.

Mammary carcinosarcoma in cat: a case report

A case of mammary carcinosarcoma is reported in a 13-year-old, mixed breed female cat, which was not spayed and had not received contraceptives. The patient presented extensive and coalescent nodules in all mammary glands. Based on the histological and immunohistochemical findings, the diagnosis of mammary carcinosarcoma was confirmed.

Lameness in a dog caused by thoracic wall invasion by a pulmonary neoplasm

A 12-year-old fox-terrier dog presented with forelimb lameness of 3-weeks duration. Ultrasonography revealed a mass within the thoracic wall and osteolysis of the left third rib. A squamous cell carcinoma was diagnosed by cytological examination of an ultrasound-guided fine needle aspirate of this mass. As a result of the diagnosis of neoplasia, the dog was euthanatized. Necropsy revealed a solitary expansile mass within the left cranial lung lobe, and a mass within the adjacent thoracic wall. Thickening of the pleura between the two masses was visible, although adhesions were not present. Histology of both masses revealed a well-differentiated squamous cell carcinoma. To the authors' knowledge, this is the first detailed description of direct invasion of the thoracic wall by a canine lung tumour.