Dermoid sinus in the perirectal fossa of a Siamese cat with involvement of the vaginal wall.

A 2.5-year-old spayed female Siamese cat was presented with a recurrent exudative wound in the right perirectal fossa. Clinical examination at presentation revealed a 1 cm long open wound with purulent discharge in the right perirectal fossa but was otherwise unremarkable. A computed tomography contrast-enhanced study showed a tracking sinus which could be traced from the right dorsolateral perianal region right up to the level of the vagina. Surgical exploration was performed from the perirectal region. The intermuscular sinus tract, which formed a cystic structure and connected to the vaginal wall, was en bloc excised. Histopathological examination confirmed the diagnosis of a dermoid sinus in the perirectal fossa with vaginal infiltration. To the authors' knowledge, this is the first case report in the veterinary literature of the successful surgical management of a dermoid sinus in the perianal region connected to the vaginal wall in a cat.

Synovial cell sarcoma in a dog: A misnomer-Cytologic and histologic findings and review of the literature.

A 4-year-old Irish Setter was presented with a history of progressive left pelvic limb lameness. Orthopedic examination revealed pain on manipulation of the left stifle. Radiographs showed an osteolytic lesion in the subchondral bone of the medial tibial condyle. Fine-needle aspirates were taken, and cytology revealed numerous cohesive clusters of plump, oval to spindloid cells often with perivascular distribution and moderate cellular atypia. A diagnosis of sarcoma was made with synovial cell sarcoma (SCS) and histiocytic sarcoma being the 2 main differentials. Histopathology confirmed the diagnosis of sarcoma and provided the same differentials. All neoplastic cells were positive for vimentin, and approximately 5% of them also stained with pan-cytokeratin using immunohistochemical staining methods. Neoplastic cells did not express CD18. The combination of this immunohistochemical profile and cell morphology was consistent with an SCS. Synovial cell sarcoma is a rare and poorly understood canine tumor entity. This is the first extensive description of the cytologic features of this neoplasm. The literature was also reviewed, focusing on comparative aspects of dogs and people, with a special emphasis on the cell of origin and diagnostic tools. Controversies regarding the nomenclature of this tumor are also presented. The authors propose a new term (cytokeratin-positive joint-associated sarcoma) for addressing this neoplasm until the cell of origin of this tumor is elucidated.

A "spaghetti sign" in feline abdominal radiographs predicts spleno-systemic collateral circulation.

A well-defined, tortuous, and tubular soft tissue opaque structure has been observed within the left mid abdominal cavity in digital radiographs of some cats. Authors hypothesized that this radiographic "spaghetti sign" is a predictor for spleno-systemic collateral circulation. The purpose of this multicenter, retrospective, descriptive study was to further characterize radiographic "spaghetti signs" in a group of cats and compare these signs with results of ultrasonography or computed tomography (CT). A multiinstitutional database was reviewed for radiographic reports describing the presence of a tubular tortuous structure within the left abdominal cavity of feline patients. Patients were included if additional abdominal ultrasound or CT studies were available. Imaging studies and medical records were retrieved and reviewed by a board-certified veterinary radiologist, and characteristics were recorded. Eighteen cats met the inclusion criteria. The presence of a tortuous vessel consistent with spleno-systemic collateral circulation was observed by ultrasonography or CT examinations in all patients with a "spaghetti sign" on abdominal radiographs. All patients were spayed females. One cat showed ultrasonographic imaging features consistent with portal hypertension. In conclusion, findings supported the hypothesis that a radiographic "spaghetti sign" is a predictor of spleno-systemic collateral circulation in feline patients and should be distinguished from other signs such as focal loss of serosal detail or a space occupying lesion.

Evaluation of the use of intra-operative radiology for open placement of lag screws for the stabilization of sacroiliac luxation in cats.

OBJECTIVES: To assess the effect of intra-operative radiology on the quality of lag screw insertion for the management of sacroiliac joint luxations in cats. METHODS: In this retrospective single-centre study, the surgical, anaesthetic and imaging records of 40 screws (32 cats) placed with lag effect for management of sacroiliac luxation were reviewed. Postoperative radiographs were assessed for sacroiliac joint reduction, screw position, and sacral width purchased by each screw. Cases were divided into two groups according to the use of (IOR) or the absence of intra-operative radiology (NIOR). RESULTS: A total of 23 lag screws were placed with the aid of intra-operative radiology and 17 without. Three of the 23 screws placed in the IOR group exited the sacrum as opposed to eight of 17 screws in the NIOR group (p = 0.03). Mean sacral width purchased by the screws in the IOR group (70.8%) was also significantly higher (p = 0.002) than in the NIOR group (54.6%). Mean general anaesthetic times for unilateral and bilateral screw placement for the IOR group and NIOR group were not significantly different. CLINICAL SIGNIFICANCE: The use of intra-operative radiology can significantly improve the quality of lag screw insertion for the stabilization of sacroiliac luxations in cats, which should lead to a reduced incidence of postoperative screw loosening.

The influence of temperature and age on the T1 relaxation time of the equine distal limb.

The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T(1) relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal intensity for a range of inversion times (TIs) at six different regions of interest (ROI): (1) distal aspect of the proximal phalanx, (2) proximal aspect of the middle phalanx, (3) distal aspect of the middle phalanx, (4) navicular bone, (5) proximal aspect of the distal phalanx, and (6) distal aspect of the distal phalanx. The T(1) of the bone marrow in the equine distal limb was calculated from the results and was found to increase by 3.13 ± 0.08 (SE) ms/°C. There was no significant effect of age (2-16 years) but the T(1) values measured from the limbs of young (< 1 year) animals were considerably longer (32.6 ± 1.7 (SE) ms). Similar effects of temperature and age were found for all measured ROIs but there were significant differences in the mean values of T(1) , ranging from +7.7 (distal aspect of the distal phalanx) to -13.2 ms (distal aspect of the proximal phalanx).