The 2-tier grading system identifies canine cutaneous and/or subcutaneous mast cell tumors with aggressive biological behavior regardless of growth model

Sabattini, Silvia; Brocanelli, Alessia; Zaccone, Riccardo; Faroni, Eugenio; Renzi, Andrea; Ciammaichella, Luca; Bettini, Giuliano; Marconato, Laura

doi:10.1177/03009858241240443

Cited by 3 publications

References 21 publications

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Reassigned surgical margins after neoadjuvant chemotherapy results in low local recurrence in dogs with mast cell tumours

Ciammaichella,

Sabattini,

Del Magno

et al. 2024

Veterinary Record

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BackgroundNeoadjuvant chemotherapy (NAC) is delivered before surgery to allow less extensive tumour resection, but the optimal surgical margin width after NAC is unknown. The aim of this study was to determine the impact of reassigned margins on local recurrence after NAC in dogs with mast cell tumours (MCTs).MethodsA retrospective analysis was conducted for dogs with MCTs undergoing NAC consisting of vinblastine and prednisolone, subsequent tumour resection and lymphadenectomy, and a minimum follow‐up of 6 months. Surgical margins were reassigned based on the size of the MCT after NAC. Pre‐ and post‐NAC measurements of MCTs were recorded. The margin status was assessed with a combined radial and tangential sectioning technique; pre‐NAC MCT cytograde and lymph node (LN) cytological status were compared with the Kiupel grade and Weishaar stage, respectively.ResultsTwenty‐two dogs were included. MCT shrinkage after NAC consistently occurred, with a median reduction rate of 40.4% (range 5%–94.5%). Margins were complete in 15 of 22 dogs, and two MCTs and three LNs appeared histologically downgraded and downstaged, respectively. Two (9.1%) MCTs recurred.LimitationsThe limitations of this study were the small sample size and relatively short follow‐up.ConclusionNAC leads to shrinkage of canine MCTs, with the resulting reassigned surgical margins being associated with a low recurrence rate.

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Reassigned surgical margins after neoadjuvant chemotherapy results in low local recurrence in dogs with mast cell tumours

Ciammaichella,

Sabattini,

Del Magno

et al. 2024

Veterinary Record

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Incorporation of Biologic Variables Into the Staging for Canine Cutaneous and Subcutaneous Mast Cell Tumours: Proposal of the UBo pTNM System

Marconato,

Faroni,

Battisti

et al. 2024

Vet Comparative Oncology

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Canine cutaneous mast cell tumours (MCTs) are currently staged based on the World Health Organization (WHO) classification, which has remained unchanged since its initial formulation. Our study aimed to assess the reliability of a novel pTNM staging system, which incorporates tumour extent (T), lymph node involvement (N), presence of distant metastases (M) and the two‐tier histologic grade. We analysed medical records of dogs with one or more cutaneous/subcutaneous completely staged MCT, undergoing tumour excision with lymphadenectomy, unless distant metastases were present, in which cases, medical therapy was administered. Dogs were categorized into three stages: I (T1‐2N0M0), II (T1‐2N1M0) and III (distant metastases). Stages I and II were further divided based on histologic grade into ‘low’ and ‘high’. Substage b was defined as the presence of tumour diameter of ≥3 cm and/or ulceration. Of 226 dogs, 87 (38.5%) were in Stage I (I‐low, n = 75; I‐high, n = 12), 107 (47.3%) in Stage II (II‐low, n = 59; II‐high, n = 48), and 32 (14.2%) in Stage III. The newly proposed staging system was able to significantly stratify the population for both time to progression and tumour‐specific survival. Compared to Stage I‐low, the risk of progression increased significantly for Stage I‐high (18.3 times), Stage II‐low (8.5 times), Stage II‐high (41.5 times) and Stage III (110.3 times). The staging system was highly prognostic for both cutaneous and subcutaneous MCTs. Prospective validation studies are essential to compare this new system with the current WHO staging and further validate its accuracy and clinical utility.

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Signalment of dogs and histopathological features of subcutaneous and cutaneous mast cell tumors

Minnoye,

De Vos,

Beck

et al. 2024

Preprint

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Background Mast cell tumors (MCTs) are the most common malignant skin neoplasms in dogs. In the past, the distinction between cutaneous MCTs (cMCTs), originating from the dermis, and subcutaneous MCTs (scMCTs), originating from the subcutaneous tissue, was not made. Histopathological differentiation, including grading, is important for prognostication. However, the Patnaik and Kiupel grading systems were proposed for cMCTs only. The objective of our study was to describe and compare the signalment of dogs with scMCTs and cMCTs and histopathological features, anticipating similarities in both groups. Data of dogs histologically diagnosed with scMCTs or cMCTs between September 2020 and July 2023 were retrospectively analyzed. Signalment, tumor location, histopathological features, completeness of removal and lymph node status were recorded. Results Data on 305 scMCTs and 1291 cMCTs were collected. Mitotic count (MC) was not different between scMCTs (1.63) and cMCTs (1.58) (P = 0.8490). Compared to cMCTs, scMCTs more often had anisokaryosis, bizarre nuclei and multinucleation. Kiupel high grade was more often assigned to scMCTs (51/292, 17.5%) than cMCTs (154/1291, 11.9%) (P = 0.009). The odds of MCTs being assigned a high grade in scMCT was 1.578 higher than in cMCTs (95% confidence interval [1.116–2.232]). Conclusions Breed distribution was different for scMCTs and cMCTs. Histopathological differences between scMCTs and cMCTs were observed. A Kiupel high grade was more often assigned to scMCTs than cMCTs. Whether these histopathological findings correlate with clinical outcome has to be established in additional studies.

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The 2-tier grading system identifies canine cutaneous and/or subcutaneous mast cell tumors with aggressive biological behavior regardless of growth model

Cited by 3 publications

References 21 publications

Reassigned surgical margins after neoadjuvant chemotherapy results in low local recurrence in dogs with mast cell tumours

Reassigned surgical margins after neoadjuvant chemotherapy results in low local recurrence in dogs with mast cell tumours

Incorporation of Biologic Variables Into the Staging for Canine Cutaneous and Subcutaneous Mast Cell Tumours: Proposal of the UBo pTNM System

Signalment of dogs and histopathological features of subcutaneous and cutaneous mast cell tumors

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