Objective -To report the outcomes associated with sentinel lymph nodes (SLNs) detection and extirpation guided by radionuclide and methylene blue injections in dogs with cutaneous and subcutaneous mast cell tumors (MCTs).Study Design -Clinical prospective cohort study. Animals -30 client-owned dogs with MCTs amenable to wide-margin excision, without evidence of distant metastasis and abnormal regional lymph nodes (RLNs).Methods -Technetium-99m and methylene blue were injected peritumorally. Dogs underwent pre-operative gamma camera scintigraphy, and an intraoperative gamma probe guided SLN extirpation. Outcomes included technical and surgical complications, number of SLNs, SLNs location respecting the expected RLN, and histopathology results.Results -SLN mapping was applied to 34 MCTs in 30 dogs without any complication.SLNs were not identified in 3/34 tumors, all with previous scar tissue. SLNs did not correspond to expected RLNs in 19/30 (63%) tumors. Histological examination confirmed an early or overt metastasis in 32/57 (56%) SLNs extirpated.Conclusion -SLN mapping and biopsy with radionuclide and injection of methylene blue was associated with low morbidity and allowed detection of SLNs in dogs with MCT at first presentation without scar tissue.Clinical significance -Incorporation of SLN mapping and extirpation allows for a personalized staging approach in dogs with MCT. The presence of scar tissue in dogs with recurrent tumors seems to be a limitation for SLN mapping with this technique.

Metastasis to regional lymph nodes (RLNs) in dogs with cutaneous mast cell tumour (cMCT) has been correlated with shortened survival time and higher risk of spread to distant sites. In the present study, extirpation of non-palpable or normal-sized RLNs was included in the surgical management of cMCT in dogs. Correlations between histological nodal status (HN0-3) and tumour variables were analysed. Ninety-three dogs with single cMCT without distant metastasis that underwent wide surgical excision of the primary tumour and extirpation of non-palpable or normal-sized RLN were included. The association between HN (HN0 vs HN > 0; HN0-1 vs HN2-3) and tumour variables (site, longest diameter, ulceration, 3-tier and 2-tier histological grades) was analysed by a generalized linear model with multinomial error. Then, 33 (35.5%) RLNs were HN0, 14 (15%) were HN1, 26 (28%) were HN2 and 20 (21.5%) were HN3. The presence of positive (HN > 0) RLN was significantly associated with cMCT larger than 3 cm. No other association was statistically significant. Non-palpable/normal-sized RLN in dogs with cMCT can harbour histologically detectable metastatic disease in nearly half of the cases. Extirpation of the RLN should always perfomed to obtain a correct staging of the disease, even in the absence of clinical suspicion of metastasis. Further studies should evaluate the possible therapeutical effect of the tumour burden reduction obtained by exrtipartion of a positive RLN.

Tumor stage is a prognostic indicator for canine malignant head and neck tumors (MHNT). However, consensus is lacking on nodal staging in the absence of clinically apparent nodal disease (cN0 neck).This prospective observational study aims to determine the diagnostic accuracy of radiopharmaceutical and blue dye for sentinel lymph node biopsy (SLNB), to assess the correspondence between sentinel lymph node (SLN) and clinically expected regional lymph node (RLN) and the impact on staging of the procedure in dogs with MHNT and cN0 neck.Twenty-three dogs with MHNT and cN0 neck underwent tumour excision and SLNB guided by preoperative lymphoscintigraphy and intraoperative gamma-probe and blue dye. Diagnostic performances and detection rate were calculated. Correspondence between SLN and RLN, number of nodes excised, histopathological status of the SLN and complications related to the procedure were recorded. The mapping technique identified at least one SLN in 19/23 dogs, with a detection rate of 83%. The SLN did not correspond to the RLN in 52% of dogs. Multiple nodes were removed in 61% of dogs. At histopathology, 8 (42%) dogs had SLN+, of which 4 differed from the RLN. Only minor self-limiting complications occurred in 5 (22%) dogs.Radiopharmaceutical and blue dye guidance is accurate (sensitivity 88.9%; specificity 100%) for SLNB in dogs with MHNT and cN0 and allowed the extirpation of unpredictable and/or multiple SLN with minimal morbidity. Incorporation of SLNB in the management of MHNT is desirable to correctly stage the cN0 neck, owing the unpredictability of the lymphatic drainage.

The recent literature supports the sentinel lymph node (SLN) biopsy in dogs with MCT due to discrepancy with the regional lymph node and the high percentage of occult metastasis. However, the SLN biopsy includes additional anesthesiologic, diagnostic, and surgical procedures, and additional costs. The study aimed to assess the association between clinicopathological variables and SLN status, determining the identification of dogs at lower risk of SLN metastases. Dogs with integumentary MCT were admitted to the lymphoscintigraphic mapping and subsequent biopsy of SLN. The association between clinicopathological variables of MCT and SLN status was statistically tested, both considering occult and overt metastasis together (HN2-HN3) and overt metastasis (HN3) alone. Fifty low-grade cutaneous MCT and 16 subcutaneous MCT were included. A small to moderate association between integumentary MCT ≥ 3 cm and HN2-HN3 SLN was found. A strong association of integumentary MCT dimension and subcutaneous MCT with HN3 SLN occurred. Dimension of low-grade cutaneous and subcutaneous MCT seems to correlate with SLN status, but additional study should confirm this data before excluding small MCT to the SLN biopsy. On the contrary, the study results induce a solid suggestion for mapping and biopsy of the SLN in MCT > 3 cm and subcutaneous MCT.

Sentinel lymph node (SLN) mapping is the current gold standard for the oncological staging of solid malignancies in humans. This prospective observational study describes the feasibility and the limits of preoperative lymphoscintigraphy for SLN detection in dogs with spontaneous malignancies and the improvements in staging accuracy. Client-owned dogs with confirmed malignant neoplasia and absence of distant metastasis were prospectively enrolled. Lymphoscintigraphy was performed after the peritumoral injection of Technetium-99m labeled nanocolloids. Regional dynamic and static images were acquired, with and without masking of the injection site with a lead shield. The dogs were then subjected to surgery for tumor excision and SLN extirpation. Intraoperative SLN detection was performed by combining methylene blue dye and a dedicated gamma probe. Overall, 51 dogs with a total of 60 solid malignant tumors were enrolled. Lymphoscintigraphy identified at least one SLN in 57 of 60 cases (95%). The SLN did not always correspond to the regional lymph node (35/57, 61.4%).The use of a lead shield, masking the injection site, markedly improved the SLN visibility. The median time of SLN appearance was 11.4 ± 9.3 min. No side effects were observed. Preoperative lymphoscintigraphy allows for SLN detection in dogs and can improve staging accuracy by either identifying the SLN in a different lymphosome than clinically expected or discriminating the draining node in uncertain cases. The combined use of preoperative and intraoperative techniques is recommended to increase the SLN detection rate.

Local recurrence (LR) is the major concern in the treatment of feline injection‐site sarcoma (FISS). Pretreatment leukocyte counts and ratios have been reported as diagnostic and/or prognostic markers in human and canine oncology. The aim of this retrospective study was to explore the prognostic impact on LR and overall survival time (OST) of pretreatment neutrophil‐to‐lymphocyte ratio (NLR), white blood cell count (WBCC), neutrophil count (NC) and lymphocyte count (LC) in cats with surgically excised FISS. Eighty‐two cats with histologically confirmed FISS at first presentation, without distant metastases, and with available pretreatment haematological analyses were retrospectively enrolled. The correlation of NLR, WBCC, NC, LC with tumour variables and patient variables was explored. NLR was correlated with tumour size (P = .004), histological pattern of tumour growth (P = .024) and histotype (P = .029), while WBCC and NC were associated with ulceration (P = .007, P = .011) and pattern of growth (P = .028, P = .004). No significant relationships emerged between LC and any of the considered variables. The impact of NLR, WBCC, NC, LC on LR and OST was then estimated in univariate and multivariate analysis. In univariate analysis, NLR, WBCC and NC were significant prognostic factors for both LR and OST. NLR, WBCC and NC remained prognostic in multivariate analysis for LR but not for OST. When NLR, WBCC and NC were jointly analysed, WBCC was the marker with the greater impact on LR. Preoperative NLR, WBCC and NC may aid in identifying cats at higher risk of LR.

Objective To describe a local interpolation flap based on the upper lip for the reconstruction of the dorsal aspect of the nasal plane in dogs. Study design Ex vivo and in vivo case report. Animals A 2‐year‐old medium‐sized spayed female mixed‐breed dog and a canine cadaver of a medium‐sized mixed‐breed dog. Methods A dorsal defect of the nasal plane of uncertain origin in a dog was reconstructed with a unilateral interpolation flap obtained from the caudal upper lip skin and mucosa (lip‐to‐nose flap). The procedure was first performed in a cadaveric model to assess its feasibility. Results The lip‐to‐nose flap allowed the reconstruction of a dorsal nasal plane defect with a satisfactory cosmetic outcome. The incorporation of the labial mucosa guaranteed a complete and uncomplicated wound healing of the flap; a small area of necrosis occurred at the donor site, which resolved in a few days. Conclusion The use of a lip‐to‐nose flap was feasible in these 2 medium‐sized dogs and led to satisfactory cosmetic outcome. Clinical significance A lip‐to‐nose flap may be considered to reconstruct dorsal nasal plane defects in dogs and allows for a cosmetic outcome.

Identification of prognostic factors for perivascular wall tumours (PWTs) is desirable to accurately predict prognosis and guide treatment. 100 and two dogs with surgically excised PWTs without distant metastasis were retrospectively enrolled in this multi‐institutional study, and the impact of pre‐treatment leukocyte parameters, clinical and histopathological variables on local recurrence (LR) and overall‐survival time (OST) were evaluated. Increasing values of white blood cell count (WBCC), neutrophil count (NC) and neutrophil‐to‐lymphocyte ratio (NLR) were significantly correlated with the hazard of LR in univariate analysis. WBCC and NC remained prognostic when adjusted for margins, grade, tumour size, location and skin ulceration, but lost their significance when adjusted for mitotic index and necrosis, whilst NLR remained prognostic only when close margins where categorised as infiltrated. Castrated males had a higher hazard of LR than intact males in univariate analysis, but significance was lost in multivariate models. Ulcerated PWTs and those located on the distal extremities had a higher hazard of LR both in univariate and multivariate analysis. Histological grade, necrosis, mitotic count, and infiltrated margins were all associated with LR both in univariate and multivariate analysis. Boxer breed, older age, ulceration, grade III, necrosis >50% and higher mitotic count were correlated with shorter OST, although breed and age lost their significance in multivariate analysis. Prognostication of surgically excised PWTs should be based on both clinical and histopathological variables. If validated in further studies, leukocyte counts and NLR may aid the clinician in identifying dogs at higher risk of LR before treatment.