Canine Subcutaneous Mast Cell Tumor

Abstract

Histologic grading schemes for canine cutaneous mast cell tumors (MCTs) were not developed for subcutaneous MCTs. Despite this, subcutaneous MCTs are currently categorized by many as grade II or higher. The aim of this investigation was to assess the pathology and clinical outcome for subcutaneous MCTs to provide a more accurate prognosis. Information on clinical outcome for 306 dogs was obtained from veterinarians and correlated with histologic features. Mean and median follow-up was 842 and 891 days, respectively (range, 3-2,305 days). Only 27 (9%) were confirmed as mast cell-related deaths. Metastasis occurred in 13 (4%), and 24 (8%) had local reoccurrence, even though 171 (56%) cases had incomplete surgical margins. Median survival time was not reached, and the estimated 6-month, 1-, 2-, and 5-year survival probabilities were 95%, 93%, 92%, and 86%, respectively. Dogs were euthanized or died as a result of local tumor reoccurrence, additional MCT development distant to the surgical site, or metastasis. Decreased survival time was linked to mitotic index (number of mitotic figures per 10 high-power fields), infiltrative growth pattern, and presence of multinucleation. Both univariable and multivariable analysis showed mitotic index to be strongly predictive of survival, local reoccurrence, and metastasis. The results of the study indicate that the majority of subcutaneous MCTs have a favorable prognosis, with extended survival times and low rates of reoccurrence and metastasis.

Histological classification and expression of markers of canine mast cell tumors

“…High-intensity MCTs have a high rate of recurrence [ 48 ]. This result is also comparable with that of Thompson [ 49 ] who found an association between the c-kit mutation and higher grade in canine cutaneous MCTs. c-kit mutations are significantly associated with a higher grade of neoplastic malignancy and also higher rates of recurrence and death.…”

Canine mast cell tumors: diagnosis, treatment, and prognosis

“…Survival times for dogs with the SQ tumors were found to be prolonged, with the majority of dogs in both papers (53 dogs and 306 dogs) not succumbing to mast cell disease. 24 , 25 Out of the 306 dogs, only 8% had local recurrence, and only 4% had metastasis. 25 Risk factors identified for local recurrence and metastasis included mitotic index (MI), infiltrative vs circumscribed histologic pattern, the presence of multinucleation, as well as Ki67, Ki67 + AgNOR, and KIT cellular localization pattern.…”

“… 25 Risk factors identified for local recurrence and metastasis included mitotic index (MI), infiltrative vs circumscribed histologic pattern, the presence of multinucleation, as well as Ki67, Ki67 + AgNOR, and KIT cellular localization pattern. 25 , 26 As most of the dogs with SQ MCTs were cured, and MI had the strongest correlation with clinical outcomes, there seems to be little need for, or benefit in, assessment of the risk factors that require additional staining.…”

“… 54 This is in contrast to a number of papers that report a much lower recurrence rate for dirty margins, generally ranging from 12% to 30%. 25 , 55 , 58 – 61 In one of these papers, only 23% of 28 dogs with incompletely resected grade II tumors experienced local regrowth. The combination of Ki67 and proliferating cell nuclear antigen scores was prognostic for local recurrence, and dogs with such recurrence had significantly decreased survival times.…”

Estabelecimento e caracterização de modelo xenotransplantável de mastocitoma canino para estudo de antineoplásicos

“…O modelo de xenotransplante tumoral a partir de amostras do paciente oncológico apresenta um bom valor preditivo nos ensaios pré-clínicos de substâncias com potencial antineoplásico Webster et al, 2004;GIL DA COSTA et al, 2007;THOMPSON et al, 2010). Mutações em c-kit também foram estudadas, sendo encontradas duplicações e deleções nos exons 11 e 12, que codificam para a região de tirosina-quinase, e que pode levar à ativação constitutiva do receptor Kit (LONDON et al, 1999;MA et al, 1999;ZEMKE, YAMINI YUZBASIYAN-GURKAN, 2002;RIVA et al, 2005;WEBSTER et al, 2006 úlceras gastrointestinais (encontradas em 35-83% dos animais com mastocitoma, ao exame necroscópico), retardo na cicatrização, hemorragia local, choque anafilático em animais com acometimento extenso do corpo e manipulação excessiva do tumor (muito raro acontecer) (KUBE et al, 1998;SEGUIN, 2003 …”