In cancer metastasis, intravasation of the invasive tumor cell (TCi) represents one of the most relevant events. During the last years, models regarding cancer cell intravasation have been proposed, such as the "endocanalicular transendothelial crossing" (ETC) theory. This theory describes the interplay between two adjacent endothelial cells and the TCi or a leukocyte during intravasation. Two endothelial cells create a channel with their cell membranes, in which the cell fits in without involving endothelial cell intercellular junctions, reaching the lumen through a transendothelial passage. In the present study, ten SCID mice were subcutaneously xenotransplanted with the HEK-EBNA293-VEGF-D cell line and euthanized after 35 days. Post-mortem examinations were performed and proper specimens from tumors were collected. Routine histology and immunohistochemistry for Ki-67, pAKT, pERK, ZEB-1, TWIST-1, F-actin, E-cadherin and LYVE-1 were performed followed by ultrastructural serial sections analysis. A novel experimental approach involving Computed Tomography (CT) combined with 3D digital model reconstruction was employed. The analysis of activated transcription factors supports that tumor cells at the periphery potentially underwent an epithelial-to-mesenchymal transition (EMT)-like process. Topographical analysis of LYVE-1 immunolabeled lymphatics revealed a peritumoral localisation. TEM investigations of the lymphatic vessels combined with 3D digital modelling enhanced the understanding of the endotheliocytes behavior during TCi intravasation, clarifying the ETC theory. Serial ultrastructural analysis performed within tumor periphery revealed numerous cells during the ETC process. Furthermore, this study demonstrates that ETC is an intravasation mode more frequently used by the TCi than by leukocytes during intravasation in the HEK

Case summary Skin tumours are the second-most common form of feline cancer after haematopoietic neoplasms and are often malignant. Cutaneous lymphoma is uncommon in cats and can be classified as epitheliotropic (typically of T-cell origin) or non-epitheliotropic (either of T-cell or B-cell origin). The present study describes a case of multifocal cutaneous non-epitheliotropic B-cell lymphoma. The skin nodules were multiple and variable in size; showed rapid progression; were alopecic and erythematous in appearance and pruritic and ulcerated; and were mostly located on the trunk. Nodule biopsies revealed the presence of uniform medium-to-large round neoplastic cells that infiltrated the dermis and subcutis. The neoplasias were consistent with a round cell cutaneous tumour and did not show evidence of epitheliotropism. Furthermore, immunohistochemical assessments indicated an immunophenotype characterised by round cells with a strong membrane and cytoplasmic positivity for the CD20 antigen, consistent with a lymphocyte of B-cell origin. Relevance and novel information Cutaneous non-epitheliotropic B-cell lymphoma in cats is rare and was previously reported to appear as single dermal and subcutaneous masses that are variable in size and generally develop in the tarsal region. To our knowledge, this is the first report to describe multifocal cutaneous non-epitheliotropic B-cell lymphoma in a cat.

The aim of this study was to describe and share employment of piezoelectic surgery and 3D printed pre‐operative surgical planning model in cat affected by temporomandibular joint ankylosis (TMJa). A 3‐year‐old neutered male domestic shorthair cat presented feeding problem was submitted for a CT scan of the head in order to investigate clinical TMJa. A 16‐slice multidetector CT scanner was used. CT scan revealed a misshapen, rounded right condylar process, with irregular and reduced TMJ space. A right condylectomy through piezoelectric surgery was performed. In order to plan the best surgical approach, a 3D printed model was used prior the surgery to easy identify the ideal angulation for condylectomy and during the surgery to verify the proper extent of the osteotomy. At 6‐month follow‐up the range of mouth opening is close to normal.

A 10‐year‐old intact female Pug dog was presented with a 3‐month history of left inguinal distension. A tentative diagnosis of cystic endometrial hyperplasia and uterine mineralisation with inguinal herniation was made together with palpation, abdominal radiographic and ultrasonographic examination. Ovariohysterectomy and hernioplasty were simultaneously performed. The left uterine horn was herniated through the inguinal ring. On histopathology, multinodular calcified uterine leiomyoma associated with a diffuse endometrial cystic hyperplasia was diagnosed. Uterine herniation should be considered in the differential diagnosis of inguinal mass in an intact bitch, and uterine neoplasia may be found as an underlying disease.

Background: Pectus excavatum is a rare congenital or developmental deformity of the chest wall that has been reported in both dogs and cats. The clinical symptoms vary in severity and are correlated with the grade of the deformity. The most severe cases are at a very high risk of intra- and post-operative complications that could be fatal. Case Description: A 3-month-old kitten was presented for severe dyspnea and exercise intolerance. After the radiographic diagnosis of severe pectus excavatum , a splint was designed based on the computed tomography scan of the kitten. A locking mechanism was applied on a dedicated pocket on the splint and secured with commercial glue. Five sutures were placed, the most caudal three with a surgical approach to the corresponding sternebra. The three caudal traction sutures were progressively tensioned during the first 2 weeks, and then tied. The splint was removed 1 month postoperatively; neither surgical nor splint-associated complications were observed. The kitten well tolerated the splint and the owner reported no further episodes of dyspnea or exercise intolerance. Vertebral and frontosagittal indexes were 3.2 and 9.1 at presentation, respectively, and 10.2 and 2.0 at 4 months postoperatively. Conclusion: The use of a patient-specific 3D-printed external splint associated with a progressive correction of the pectus excavatum can be a better solution for the treatment of severe cases of pectus excavatum , where a sudden distension of the rib cage could cause re-expansion injuries.