Teat sinus and duct adenomatous hyperplasia in dogs.

Seventeen lesions diagnosed as teat sinus and duct adenomatous hyperplasia were identified in 10 dogs. All of the dogs were small breeds. Six were spayed female and 4 were male, 3 castrated and 1 intact. In 5 cases, the lesions involved multiple teats. They were pink to black, flattened to round, and sometimes crusted. Histologically, the lesions were usually pigmented (16/17), plaque-like to nodular masses composed of polygonal cells arranged in anastomosing trabeculae and bilayered ducts and/or cysts, with a fibrous to mucinous (Alcian blue-positive) stroma and squamous cysts (12/17). Scattered epithelial cells contained single, discrete, clear cytoplasmic vacuoles. Atypia was mild, and the mitotic count per 2.37 mm2 varied from 0 to 15 (average 2.7). Immunohistochemistry was performed on 14 of the lesions from 8 dogs. Epithelial cells were 100% panCK+ and included basally located CK14+/CK5_6+/p63+/calponin- cells and nonbasal CK19+/CK7+ cells. Cells manifesting squamous differentiation were usually panCK+/CK14+/CK5_6+/CK19-/CK7-/p63±/calponin-. In addition to fibroblasts, vimentin positivity was found in disseminated, round to stellate stromal and intraepithelial cells that often had black, granular, cytoplasmic pigment (consistent with dendritic/phagocytic cells and/or melanocytes). Of the 8 dogs for which clinical follow-up information was available, all were still alive and well, with no significant teat changes, development of mammary lesions or other masses 4 to 22 months (median 12.5) after biopsy. The histologic, immunohistochemical, and clinical findings were consistent with teat duct and sinus adenomatous hyperplasia. This is an uncommon, benign proliferative lesion that can involve multiple teats of female and male, small breed dogs.

International Guidelines for Veterinary Tumor Pathology: A Call to Action.

Standardization of tumor assessment lays the foundation for validation of grading systems, permits reproducibility of oncologic studies among investigators, and increases confidence in the significance of study results. Currently, there is minimal methodological standardization for assessing tumors in veterinary medicine, with few attempts to validate published protocols and grading schemes. The current article attempts to address these shortcomings by providing standard guidelines for tumor assessment parameters and protocols for evaluating specific tumor types. More detailed information is available in the Supplemental Files, the intention of which is 2-fold: publication as part of this commentary, but more importantly, these will be available as "living documents" on a website (www.vetcancerprotocols.org), which will be updated as new information is presented in the peer-reviewed literature. Our hope is that veterinary pathologists will agree that this initiative is needed, and will contribute to and utilize this information for routine diagnostic work and oncologic studies. Journal editors and reviewers can utilize checklists to ensure publications include sufficient detail and standardized methods of tumor assessment. To maintain the relevance of the guidelines and protocols, it is critical that the information is periodically updated and revised as new studies are published and validated with the intent of providing a repository of this information. Our hope is that this initiative (a continuation of efforts published in this journal in 2011) will facilitate collaboration and reproducibility between pathologists and institutions, increase case numbers, and strengthen clinical research findings, thus ensuring continued progress in veterinary oncologic pathology and improving patient care.

Canine Ependymoma: Diagnostic Criteria and Common Pitfalls.

Reports of canine ependymoma are generally restricted to single case reports with tumor incidence estimated at 2% to 3% of primary central nervous system (CNS) tumors. While most commonly reported in the lateral ventricle, tumors can occur anywhere in the ventricular system and in extraventricular locations. Rosettes and pseudorosettes are a common histologic feature; however, these features can be mimicked by other CNS neoplasms. Thirty-seven potential ependymoma cases were identified in a retrospective database search of 8 institutions, and a histologic review of all cases was conducted. Of 37 cases, 22 candidate cases were further subjected to a consensus histologic and immunohistochemical review, and only 5 of 37 (13.5%) were conclusively identified as ependymoma. The neuroanatomic locations were the lateral ventricle (3/5), third ventricle (1/5), and mesencephalic aqueduct (1/5). Subtypes were papillary (4/5) and tanycytic (1/5). Histologic features included rosettes (5/5), pseudorosettes (5/5), ependymal canals (2/5), tanycytic differentiation (1/5), blepharoplasts (1/5), ciliated cells (1/5), and high nuclear to cytoplasmic ratio (5/5). Immunolabeling for GFAP (4/4) and CKAE1/3 (3/4) was found in pseudorosettes, rosettes, and scattered individual neoplastic cells. Diffuse but variably intense cytoplasmic S100 immunolabeling was detected in 3 of 4 cases. Olig2 intranuclear immunolabeling was observed in less than 1% of the neoplastic cells (3/3). Tumors that had pseudorosettes and mimicked ependymoma included oligodendroglioma, choroid plexus tumor, pituitary corticotroph adenoma, papillary meningioma, and suprasellar germ cell tumor. These findings indicate that canine ependymoma is an extremely rare neoplasm with histomorphologic features that overlap with other primary CNS neoplasms.

Lafora's-like disease in a fennec fox (Vulpes zerda).

A 6-yr-old captive-born female fennec fox (Vulpes zerda) had a history of multiple seizures and was treated with diazepam and phenobarbital therapy. Despite medical treatment, the seizures continued. They were intermittent and progressive, resulting in neurologic deficits and death of the animal within 6 mo of onset of the clinical signs. At necropsy, the animal was in good nutritional condition, and no gross lesions were noted in the brain. Histologically, amphophilic to basophilic, periodic acid-Schiff (PAS) positive, diastase-resistant inclusions were present in the brain, heart, and liver. Ultrastructurally, the inclusions were variably electron dense, fibrillary to occasionally granular, and non-membrane bound. The clinical, histologic, and ultrastructural findings were consistent with Lafora's disease, which in humans is a rare, fatal, autosomal recessive hereditary neurometabolic disorder characterized by progressive myoclonic epilepsy. This is the first report of Lafora's-like disease in a fennec fox.

Hepatic Calyptospora sp. (Apicomplexa) infection in a wild-born, aquarium-held clutch of juvenile arapaima Arapaima gigas (Osteoglossidae).

From Manaus, Brazil, 12 juvenile arapaima Arapaima gigas were imported to the United States and sent to 2 public aquaria, 1 private hobbyist, and 1 retailer. All 12 fish became ill within 4 to 6 wk of arrival, with signs of anorexia, lethargy, depigmentation, and ascites, and subsequently died despite antibiotic and anthelminthic therapy. Gross necropsies of 7 fish revealed serosanguinous coelomic effusion in all 7 fish, and branchial monogeneosis in 3 of 6 fish. The monogeneans from 1 fish were identified as Dawestrema cycloancistrium (Ancyrocephalinae). Histologic examination of 7 fish showed a variety of lesions, principally in the liver, gills, brain and gastro-intestinal tract. Numerous coccidian oocysts replaced 15 to 33% of the liver parenchyma in 6 of 7 fish examined. Light and transmission electron microscopy revealed that each oocyst contained 4 pyriform sporocysts bearing numerous sporopodia on their tapering, posterior end; approximately 25 to 30% of the length of the sporocyst was adorned. Each sporocyst was covered by a thin, membranous veil, contained 2 sporozoites, and stained brilliant pink with the Ziehl-Neelsen acid-fast method. This morphology is consistent with that of Calyptospora sp. (Lack of fresh material precluded determination to species.) This is the first report of Calyptospora sp. in arapaima. The Calyptospora sp. infection probably contributed to the morbidity and mortality of the captive arapaima.