Estimativa estereológica do volume nuclear médio ponderado como um fator prognóstico em mastocitomas subcutâneos caninos
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2024
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Os mastocitomas subcutâneos caninos são tumores normalmente considerados menos agressivos; no entanto, a ausência de um consenso é notória, e não há concordância para os seus factores de prognóstico, o que resulta na carência de validação sólida. O esquema de classificação mais usados para mastocitomas subcutâneos caninos (critérios de Thompson) associa o padrão de crescimento tumoral, uma contagem mitótica superior a 4 em 10 campos de visualização microscópica e a presença de células multinucleadas como fatores preditores da evolução clínica. Porém, estes parâmetros estão sujeitos a viés e variação interobservador. Este estudo avalia o significado prognóstico do volume nuclear médio ponderado, uma estimative estereológica que fornece a perceção do tamanho nuclear e da sua variabilidade, em mastocitomas subcutâneos caninos. Trinta mastocitomas subcutâneos caninos foram selecionados de acordo com a sua evolução clínica e foi estimado o seu volume nuclear médio ponderado com o método point- sampled intercept. Para os critérios de Thompson, não se identificou significado estatístico entre os padrões de crescimento, evolução clínica e volume nuclear médio ponderado, mesmo que o padrão infiltrativo tenha mostrado uma tendência para representar o grupo de evolução clínica negative e maiores valores de volume nuclear médio ponderado. Ao comparar o volume nuclear médio ponderado e a evolução clínica, observou-se significado estatístico. Casos com evolução clínica negative exibiram valores de volume nuclear médio ponderado superiores (media = 174.4) ao contrário dos casos com evolução clínica favorável (media = 105.1). Adicionalmente, determinou-se dpos valores de cut-off 143 μm³ e 165.8 μm³. Valores inferiores ao cut-off de 143 μm³, 94% dos cães estavam vivos dois anos depois do diagnóstico, enquanto valores iguais ou superior a 165.8 μm³, 80% dos cães faleceram. Este estudo indica que o volume nuclear médio ponderado possui elevado reprodutibilidade e pode ser usado como um fator de prognóstico independente para a classificação dos mastocitomas subcutâneos caninos. Palavras-chave: canino; mastocitoma subcutâneo; estereologia; volume nuclear médio ponderado; prognóstico
Canine subcutaneous mast cell tumors are commonly perceived as less aggressive; nevertheless, there is a notable absence of consensus, and agreement on prognostic factors remains elusive, lacking robust validation. The most widely used classification scheme for canine subcutaneous mast cell tumors (Thompson’s criteria) associate pattern of growth, a mitotic count higher than 4 in 10 high power fields and the presence of multinucleated cells as predictors of negative outcome. These parameters are however prone to interobserver variability and bias. This study assesses the prognostic significance of volume-weighted mean nuclear volume, a stereological estimation offering insights into nuclear size and its variability, in canine subcutaneous mast cell tumors. Thirty canine subcutaneous mast cell tumors were selected with information regarding outcome and volume-weighted mean nuclear volume was estimated using the “point-sampled intercept” method. Regarding Thompson’s criteria, no statistically significant differences were identified between patterns, clinical outcome, and volume-weighted mean nuclear volume, even if the infiltrative pattern showed a tendency to be more represented on the negative outcome group and with higher volume-weighted mean nuclear volume values. When comparing volume-weighted mean nuclear volume and clinical outcome a statistically significant difference emerged. Cases with a negative outcome exhibited higher volume- weighted mean nuclear volume values (average = 174.4) than cases with a favorable outcome (average = 105.1). Additionally, two cutoff values were determined, 143 μm³ and 165.8 μm³. With cutoff values bellow 143 μm³, 94% of dogs were alive two years after diagnosis, while with cutoff values equal or higher than 165.8 μm³, 80% of dogs were dead. This study indicates that volume-weighted mean nuclear volume is highly reproducible and can be used as an independent prognostic factor for classifying canine subcutaneous mast cell tumors. Keywords: canine; subcutaneous mast cell tumour; stereology; volume-weighted mean nuclear volume; prognosis
Canine subcutaneous mast cell tumors are commonly perceived as less aggressive; nevertheless, there is a notable absence of consensus, and agreement on prognostic factors remains elusive, lacking robust validation. The most widely used classification scheme for canine subcutaneous mast cell tumors (Thompson’s criteria) associate pattern of growth, a mitotic count higher than 4 in 10 high power fields and the presence of multinucleated cells as predictors of negative outcome. These parameters are however prone to interobserver variability and bias. This study assesses the prognostic significance of volume-weighted mean nuclear volume, a stereological estimation offering insights into nuclear size and its variability, in canine subcutaneous mast cell tumors. Thirty canine subcutaneous mast cell tumors were selected with information regarding outcome and volume-weighted mean nuclear volume was estimated using the “point-sampled intercept” method. Regarding Thompson’s criteria, no statistically significant differences were identified between patterns, clinical outcome, and volume-weighted mean nuclear volume, even if the infiltrative pattern showed a tendency to be more represented on the negative outcome group and with higher volume-weighted mean nuclear volume values. When comparing volume-weighted mean nuclear volume and clinical outcome a statistically significant difference emerged. Cases with a negative outcome exhibited higher volume- weighted mean nuclear volume values (average = 174.4) than cases with a favorable outcome (average = 105.1). Additionally, two cutoff values were determined, 143 μm³ and 165.8 μm³. With cutoff values bellow 143 μm³, 94% of dogs were alive two years after diagnosis, while with cutoff values equal or higher than 165.8 μm³, 80% of dogs were dead. This study indicates that volume-weighted mean nuclear volume is highly reproducible and can be used as an independent prognostic factor for classifying canine subcutaneous mast cell tumors. Keywords: canine; subcutaneous mast cell tumour; stereology; volume-weighted mean nuclear volume; prognosis
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VETERINARY MEDICINE, DOGS, MAST CELL TUMOR, PROGNOSIS, MORPHOMETRY, MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, VETERINÁRIA, MEDICINA VETERINÁRIA, CÃES, MASTOCITOMAS, PROGNÓSTICOS, MORFOMETRIA, Mestrado Integrado em Medicina Veterinária