Cytological differentiation between benign and malignant perianal gland proliferative lesions in dogs: a preliminary study.

OBJECTIVES: To evaluate the diagnostic utility of individual cytological criteria and their best combination to differentiate benign from malignant perianal gland proliferative lesions in dogs. MATERIALS AND METHODS: Retrospective study of cytological samples of canine perianal gland proliferative lesions that had subsequent histopathological confirmation. RESULTS: Seventy-seven perianal gland nodules from 56 dogs were included. Histologically, lesions were diagnosed as hyperplasia (n=2), adenoma (n=53), epithelioma (n=6) and carcinoma (n=16). Of the 28 cytological criteria assessed, 13 showed promise for distinguishing benign from malignant lesions. A diagnostic algorithm with an 87% accuracy (sensitivity, 90.9%; specificity, 85.4%) was developed from these data. CLINICAL SIGNIFICANCE: Cytological evaluation can provide useful information for presurgical differentiation between benign and malignant hepatoid gland proliferative lesions. The proposed algorithm must be validated and tested for reproducibility in further, preferably larger, series of cases.

Comparison between May-Grünwald-Giemsa and rapid cytological stains in fine-needle aspirates of canine mast cell tumour: Diagnostic and prognostic implications.

Mast cell tumours (MCTs) are often diagnosed by cytology based on the identification of purple intracytoplasmic granules with methanolic Romanowsky stains, including May-Grünwald-Giemsa (MGG). In clinical practice, aqueous rapid stains (RS) are commonly used, but mast cell granules may not stain properly. Aim of this prospective study was to investigate the frequency of MCT hypogranularity with RS and its potential implications in tumour identification, cytological grading assessment and recognition of nodal metastatic disease. Cytological preparations of canine primary MCTs and metastatic lymph nodes with subsequent histopathological confirmation were included. For each case, good-quality smears were stained with both MGG and RS and comparatively assessed. Eleven of 60 (18.3%) primary MCTs were hypogranular with RS; 9 of them were histologically high-grade tumours and in 3 cases (5%) a definitive MCT diagnosis could not be made. Accuracy in cytological grading assessment (85%) did not differ between RS and MGG. Thirteen of 28 (46.4%) metastatic lymph nodes were hypogranular with RS and 3 independent observers failed to identify nodal MCT metastases in 7% to 18% of RS-stained smears. This study confirms that, in limited cases, RS can be ineffective in staining MCT granules, particularly in high-grade tumours, thus making diagnosis more dependent on experience and quality of preparations. In dubious cases, methanolic stains should be applied. The use of RS is discouraged for the search of nodal metastases, as the identification of isolated mast cells can be more challenging.

Comparative Assessment of the Accuracy of Cytological and Histologic Biopsies in the Diagnosis of Canine Bone Lesions.

BACKGROUND: Osteosarcoma (OSA) should be differentiated from other less frequent primary bone neoplasms, metastatic disease, and tumor-like lesions, as treatment and prognosis can vary accordingly. Hence, a preoperative histologic diagnosis is generally preferred. This requires collection of multiple biopsies under general anesthesia, with possible complications, including pathological fractures. Fine-needle aspiration cytology would allow an earlier diagnosis with a significant reduction of discomfort and morbidity. HYPOTHESIS/OBJECTIVES: The aim of this study was to compare the accuracy of cytological and histologic biopsies in the diagnosis of canine osteodestructive lesions. ANIMALS: Sixty-eight dogs with bone lesions. METHODS: Retrospective study. Accuracy was assessed by comparing the former diagnosis with the final histologic diagnosis on surgical or post-mortem samples or, in the case of non-neoplastic lesions, with follow-up information. RESULTS: The study included 50 primary malignant bone tumors (40 OSAs, 5 chondrosarcomas, 2 fibrosarcomas, and 3 poorly differentiated sarcomas), 6 carcinoma metastases, and 12 non-neoplastic lesions. Accuracy was 83% for cytology (sensitivity, 83.3%; specificity, 80%) and 82.1% for histology (sensitivity, 72.2%; specificity, 100%). Tumor type was correctly identified cytologically and histologically in 50 and 55.5% of cases, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: The accuracy of cytology was similar to histology, even in the determination of tumor type. In no case was a benign lesion diagnosed as malignant on cytology. This is the most important error to prevent, as treatment for malignant bone tumors includes aggressive surgery. Being a reliable diagnostic method, cytology should be further considered to aid decisions in the preoperative setting of canine bone lesions.

Evaluation of mean echogenicity of tendons and ligaments of the metacarpal region in neonatal foals: A preliminary study.

The aims of this research were to evaluate mean echogenicity (ME) of the deep and superficial digital flexor tendons (DDFT and SDFT), the interosseous muscle (IM), and the accessory ligament of the deep digital flexor tendon (ALDDFT) of the metacarpal region in neonatal foals, and determine the effect of sex, side and body weight on this quantitative ultrasonographic evaluation. Thirteen orthopedically sound neonatal foals were examined. Four areas of study (1A, 1B, 2A, 2B) were identified. Transverse scans of the DDFT, SDFT, IM and ALDDFT were obtained, recorded, and analyzed. The most echogenic structures were the ALDDFT and DDFT, while the SDFT was significantly less echogenic than all other structures (P<0.05). No influence of sex, forelimb, or body weight was observed. The echogenicity of the tenodesmic structures of foals partially overlapped that reported in the metacarpal region in adult horses, except for IM.

Prognostic significance of Kit receptor tyrosine kinase dysregulations in feline cutaneous mast cell tumors.

Feline cutaneous mast cell tumors (FeCMCTs) are characterized by variable biological behavior. Development of multiple nodules and potential visceral involvement, along with inconsistency of conventional prognostic aids, justify uncertainty in differentiating benign from malignant forms. c-Kit proto-oncogene activating mutations have been reported in feline mast cell tumors (MCTs), but their prognostic relevance was not investigated. This study was performed on FeCMCTs with variable clinical outcome to assess whether Kit cytoplasmic immunohistochemical labeling can be regarded as indicative of c-Kit mutations and to evaluate the relationship between Kit dysregulation and survival. Twenty-four cats diagnosed with a primary cutaneous MCT were enrolled. Kit immunohistochemical pattern and c-Kit (exons 8, 9, 11) mutational status were assessed in 34 tumor samples. Risk factors affecting survival were a number of mitoses greater than 5 per 10 HPFs (P = .017) and cytoplasmic Kit labeling (P = .045). Increased mitotic activity was associated with Kit cytoplasmic expression (P = .01). c-Kit encoding mutations were present in 19 (56%) tumors (exon 8, 19%; exon 9, 71%; exon 11, 10%), however, they were not significantly related to protein expression and they had no influence on prognosis. Additionally, in 6 of 9 (67%) cats, multiple nodules from the same cat had different mutational statuses. Mutations in the fifth immunoglobulin-like domain of Kit occur frequently in FeCMCT, but they are variably associated with aberrant protein expression and do not appear to be strictly correlated with biological behavior. These findings need to be confirmed in larger series, and exploration of further genomic regions of c-Kit is warranted.

Nodular dermatofibrosis in a dog without a renal tumour or a mutation in the folliculin gene.

Canine nodular dermatofibrosis is a rare skin disease associated with renal cystadenoma or cystadenocarcinoma and uncommonly with uterine leiomyoma. It is generally seen in German shepherd dogs, but has been also reported in other breeds, and a relationship has been suggested with mutation of the gene encoding folliculin (FLCN), which is located on chromosome 5. A 10-year-old female golden retriever was presented because of numerous firm cutaneous nodules up to 4 cm in diameter over the entire body surface. Cytological and histopathological examinations confirmed generalized cutaneous nodular dermatofibrosis, but ultrasonography of both kidneys ruled out renal neoplasia. Ovariohysterectomy was performed because of prolonged oestrus periods. Microscopical examination of the excised tissues confirmed the absence of uterine neoplasia, but identified rete adenoma of the right ovary. Abdominal ultrasound performed repeatedly over a 5-year follow-up period did not identify any alteration in the renal parenchyma. Molecular studies excluded the presence of any mutation in the FLCN gene.

The performance of poly-epsilon-caprolactone scaffolds in a rabbit femur model with and without autologous stromal cells and BMP4.

The ability of a cellular construct to guide and promote tissue repair strongly relies on three components, namely, cell, scaffold and growth factors. We aimed to investigate the osteopromotive properties of cellular constructs composed of poly-epsilon-caprolactone (PCL) and rabbit bone marrow stromal cells (BMSCs), or BMSCs engineered to express bone morphogenetic protein 4 (BMP4). Highly porous biodegradable PCL scaffolds were obtained via phase inversion/salt leaching technique. BMSCs and transfected BMSCs were seeded within the scaffolds by using an alternate flow perfusion system and implanted into non-critical size defects in New Zealand rabbit femurs. In vivo biocompatibility, osteogenic and angiogenic effects induced by the presence of scaffolds were assessed by histology and histomorphometry of the femurs, retrieved 4 and 8 weeks after surgery. PCL without cells showed scarce bone formation at the scaffold-bone interface (29% bone/implant contact and 62% fibrous tissue/implant contact) and scarce PCL resorption (16%). Conversely, PCL seeded with autologous BMSCs stimulated new tissue formation into the macropores of the implant (20%) and neo-tissue vascularization. Finally, the BMP4-expressing BMSCs strongly favoured osteoinductivity of cellular constructs, as demonstrated by a more extensive bone/scaffold contact.