Ancillary techniques on the evaluation of canine cutaneous mast cell tumors from Brazil

ABSTRACT: The use of histologic classification by a 2-tier grading system only, immunohistochemistry (IHC) for KIT and Ki-67 and polymerase chain reaction (PCR) for internal tandem duplications (ITD) on exon 11 has improved the prognostication of canine cutaneous mast cell tumors (CCMTs) particularly in the United States. However, these techniques are not commonly used in most Brazilian laboratories. Likewise, no studies, to date, have investigated the occurrence of ITD in CCMTs from the country. Thus, this study tested the 2-tier grading system, the immunohistochemistry for KIT and Ki-67 and the PCR for exon 11 in a group of Brazilian CCMTs with the goal of investigating the applicability of these tests in a Brazilian laboratory. Of the 39 CCMTs, 69.2% (27/39) were identified as low-grade and 30.8% (12/39) as high-grade by a 2-tier grading system. All tumors had a KIT expression pattern II, and 30.6% (11/36) had a high growth fraction (Ki-67). PCR amplification was successful in four of the 11 tumors examined. Two of these (50%) were positive for ITD. This study highlights the importance of using auxiliary techniques in the CCMT evaluation, identifies limitations and confirms the applicability of these methods on a routine diagnostic basis in Brazil. Our results will help to improve the prognostication of CCMTs in Brazilian diagnostic laboratories, encouraging the use of supplementary methods.

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Grading Cutaneous Mast Cell Tumors in Cats

Veterinary Pathology ◽

10.1177/0300985818800028 ◽

2018 ◽

Vol 56 (1) ◽

pp. 43-49 ◽

Cited By ~ 3

Author(s):

Silvia Sabattini ◽

Giuliano Bettini

Keyword(s):

Mast Cell ◽

Case Series ◽

Surgical Excision ◽

Skin Neoplasms ◽

Grading System ◽

Low Grade ◽

Tumor Diameter ◽

High Grade ◽

Mast Cell Tumors ◽

Cutaneous Mast Cell

Cutaneous mast cell tumors (cMCTs) account for approximately 20% of skin neoplasms in cats. As there is no grading system for these tumors, prognosis is difficult to estimate. Although the typical presentation is a benign tumor that can be cured by surgical excision, a small but important proportion of feline cMCTs is biologically aggressive and can spread to local lymph nodes, precede the onset of disseminated cutaneous disease, or be associated with visceral involvement. A number of macroscopic and histologic features were retrospectively evaluated in cases of feline cMCTs treated with surgical excision with or without medical therapy. Cats were divided into 2 groups based on the clinical outcome. Group 1 included cats alive with no mast cell tumor–related disease at 1000 days from surgery; group 2 included cats developing histologically confirmed metastatic or cutaneous disseminated disease. The criteria allowing the best differentiation between the groups were used to develop a grading scheme. Groups 1 and 2 were composed by 48 (76%) and 15 (24%) cases, respectively. Tumors were classified as high grade if there were >5 mitotic figures in 10 fields (400×) and at least 2 of the following criteria: tumor diameter >1.5 cm, irregular nuclear shape, and nucleolar prominence/chromatin clusters. According to this scheme, the 15 (24%) high-grade cMCTs had significantly reduced survival time (median, 349 days; 95% CI, 0–739 days) as compared with the 48 low-grade tumors (median not reached; P < .001). Further studies are warranted to validate this grading system and test reproducibility on a larger case series.

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Stereology in Grading and Prognosis of Canine Cutaneous Mast Cell Tumors

Veterinary Pathology ◽

10.1177/0300985820985138 ◽

2021 ◽

pp. 030098582098513

Author(s):

Mafalda Casanova ◽

Sandra Branco ◽

Inês Berenguer Veiga ◽

André Barros ◽

Pedro Faísca

Keyword(s):

Mast Cell ◽

Clinical Outcome ◽

Prognostic Value ◽

Histological Grade ◽

Intraobserver Variability ◽

Low Grade ◽

High Grade ◽

Mast Cell Tumors ◽

Cutaneous Mast Cell ◽

Grade Iii

Canine cutaneous mast cell tumors (ccMCTs) are currently graded according to Patnaik and Kiupel grading schemes. The qualitative and semiquantitative parameters applied in these schemes may lead to inter- and intraobserver variability. This study investigates the prognostic value of volume-weighted mean nuclear volume ([Formula: see text]), a stereological estimation that provides information about nuclear size and its variability. [Formula: see text] of 55 ccMCTs was estimated using the “point-sampled intercept” method and compared with histological grade and clinical outcome. The clinical history of dogs treated with surgical excision alone was available for 30 ccMCTs. Statistical differences in [Formula: see text] were found between grade II ([Formula: see text]= 115 ± 29 µm3) and grade III ccMCTs ([Formula: see text]= 197 ± 63 µm3), as well as between low-grade ([Formula: see text]= 113 ± 28 µm3) and high-grade ccMCTs ([Formula: see text]= 184 ± 63 µm3). An optimal cutoff value of [Formula: see text] ≥ 150 µm3 and [Formula: see text] ≥ 140 µm3 was determined for grade III and high-grade ccMCTs, respectively. In terms of prognosis, [Formula: see text] was not able to predict the clinical outcome in 42% of the cases; however, cases with [Formula: see text]<125 µm3 had a favorable outcome. These results indicate that, despite having limited prognostic value when used as a solitary parameter, [Formula: see text] is highly reproducible and is associated with histological grade as well as with benign behavior.

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The Relevance of CD117-Immunocytochemistry Staining Patterns to Mutational Exon-11 inc-kitDetected by PCR from Fine-Needle Aspirated Canine Mast Cell Tumor Cells

Veterinary Medicine International ◽

10.1155/2014/787498 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 9

Author(s):

A. Sailasuta ◽

D. Ketpun ◽

P. Piyaviriyakul ◽

S. Theerawatanasirikul ◽

P. Theewasutrakul ◽

...

Keyword(s):

Mast Cell ◽

Needle Aspiration ◽

Biological Behavior ◽

High Grade ◽

Fine Needle ◽

Mast Cell Tumors ◽

Diagnosis And Prognosis ◽

Cutaneous Mast Cell ◽

Exon 11 ◽

Two Parameters

Canine cutaneous mast cell tumors (MCT) are the lethal skin tumors. The biological behavior of the MCT cells is quite varied and unpredictable. Almost MCT dogs usually require a rapid diagnosis and therapy. However, MCT diagnosis and prognosis are still dependent on histopathology which is rather inconvenient, time-consuming, painful, and harmful for some cases. Indeed, MCT can be easily accessible using fine-needle aspiration (FNA). In this study, our biopsy specimens were classified as low- and high-grade MCT based on the novel 2-tier histopathologic grading system. We have demonstrated the usage of fine-needle aspirated MCT cells (FNA-MCT cells) from these specimens as a primary cell source to study the distribution of CD117-immunocytochemistry (CD117-ICC) staining patterns and the frequency of internal tandem duplication- (ITD-) mutant exon-11 ofc-kit. The result has substantially shown that there were three staining patterns identified in the cells. Only paranuclear pattern was significantly increased in the cells from high-grade MCT. Altogether, the ITD-mutant exon-11 was also detectable only in these cells. Therefore, the result has supported our hypothesis that there was an increased opportunity to observe a higher CD117-ICC staining pattern and exon-11 mutation in high-grade MCT; even these two parameters may not precisely indicate a histopathological grade.

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A retrospective study on prophylactic regional lymphadenectomy versus nodal observation only in the management of dogs with stage I, completely resected, low-grade cutaneous mast cell tumors

10.21203/rs.3.rs-156548/v1 ◽

2021 ◽

Author(s):

Silvia Sabattini ◽

Matti Kiupel ◽

Riccardo Finotello ◽

Damiano Stefanello ◽

Eugenio Faroni ◽

...

Keyword(s):

Mast Cell ◽

Stage I ◽

Low Grade ◽

Term Outcome ◽

Long Term Outcome ◽

Mast Cell Tumors ◽

Regional Lymphadenectomy ◽

Significant Difference ◽

Cutaneous Mast Cell ◽

Prophylactic Lymphadenectomy

Abstract Background. While lymphadenectomy of metastatic 27 lymph nodes (LNs) has been associated with improved outcome, the clinical utility of prophylactic lymphadenectomy in dogs with stage I cutaneous mast cell tumors (cMCTs) remains a controversial topic. To assess the therapeutic role of lymphadenectomy of uninvolved regional LNs, the long-term outcome of cMCT-bearing dogs with cytologically negative and surgically unresected regional LNs (observation only, OO) was compared with that of dogs with a surgically resected and histologically negative regional LNs (prophylactic regional lymphadenectomy, PRL).Results. A retrospective analysis of 64 dogs with a low-grade, completely resected stage I cMCT was performed: (54.7%) dogs were subjected to OO and 29 (45.3%) underwent PRL. Dogs were monitored for a median of 813 and 763 days in the OO group and PRL group, respectively. The number of dogs undergoing MCT progression was significantly higher in the OO group (P = 0.028) and curve comparison revealed a tendency to a better time to progression in the PRL group (P = 0.058). No significant difference in survival time (P = 0.294) was observed between dogs in the OO and PRL groups.Conclusions. Our results showed that lack of immediate lymphadenectomy was associated with a higher risk for tumor progression. This preliminary judgement, reinforced by the findings that lymphadenectomy was well tolerated in all cases, and that histopathology provides the definitive assessment of the nodal pathological status, may suggest that prophylactic lymphadenectomy is indicated in the management of stage I MCTs. Larger prospective studies are warranted for generating clinical evidence of this latter hypothesis.

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Expression of Ki67, BCL-2, and COX-2 in Canine Cutaneous Mast Cell Tumors

Veterinary Pathology ◽

10.1177/0300985812447829 ◽

2012 ◽

Vol 50 (1) ◽

pp. 110-121 ◽

Cited By ~ 42

Author(s):

M. Vascellari ◽

M. Giantin ◽

K. Capello ◽

A. Carminato ◽

E. M. Morello ◽

...

Keyword(s):

Mast Cell ◽

Health Status ◽

Mortality Rate ◽

Protein Expression ◽

Tumor Grade ◽

Grading System ◽

High Grade ◽

Mast Cell Tumors ◽

Cox 2 ◽

Cutaneous Mast Cell

The expression of Ki67, BCL-2, and COX-2 was investigated in 53 canine cutaneous mast cell tumors (MCTs) by immunohistochemistry and quantitative real time polymerase chain reaction (qPCR) to evaluate their prognostic significance and the association with the histologic grading and the mitotic index (MI). MCTs were graded according to the Patnaik grading system and the novel 2-tier grading system proposed by Kiupel. The numbers of mitotic figures/10 high-power fields (MI) were counted. Both grading systems were significantly associated with prognosis. The Patnaik grading was of limited prognostic value for grade 2 MCTs, with 23% being associated with mortality. The concordance among pathologists was strongly improved by the application of the 2-tier grading system, and 71% of high-grade MCTs were associated with a high mortality rate. MI and Ki67 protein expression were significantly associated with grading and survival. No significant association between BCL-2 protein expression and either grading system or health status was observed. BCL-2 mRNA expression was significantly higher in grade 2 than in grade 1 MCTs, while no statistically significant differences were detected between low- and high-grade MCTs. The increased BCL-2 mRNA level was significantly associated with increased mortality rate. The COX-2 protein expression was detected in 78% of the MCTs investigated. However, neither association with the tumor grade nor with the health status was observed. COX-2 mRNA was significantly up-regulated in MCTs compared to surgical margins and control skin tissue, but it was neither associated with tumor grade nor with survival.

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Mutations in C-KIT exon 11 in canine cutaneous mast cell tumors

BMC Proceedings ◽

10.1186/1753-6561-7-s2-p56 ◽

2013 ◽

Vol 7 (S2) ◽

Author(s):

Rafael T Neto ◽

Didir Q Cagnini ◽

Renée L Amorim

Keyword(s):

Mast Cell ◽

Mast Cell Tumors ◽

Cutaneous Mast Cell ◽

Exon 11

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c-KIT messenger RNA and protein expression and mutations in canine cutaneous mast cell tumors

Journal of Veterinary Diagnostic Investigation ◽

10.1177/1040638711425945 ◽

2011 ◽

Vol 24 (1) ◽

pp. 116-126 ◽

Cited By ~ 28

Author(s):

Mery Giantin ◽

Marta Vascellari ◽

Emanuela Maria Morello ◽

Katia Capello ◽

Antonella Vercelli ◽

...

Keyword(s):

Mast Cell ◽

Messenger Rna ◽

Staining Pattern ◽

Protein Localization ◽

Tumor Grade ◽

Low Grade ◽

Histological Grading ◽

Proliferation Markers ◽

Mast Cell Tumors ◽

Cutaneous Mast Cell

Cutaneous mast cell tumors (MCTs) are among the most common neoplasms in dogs and show a highly variable biologic behavior. Histological grading, cell proliferation markers, and KIT immunohistochemistry are typically used to predict post-surgical prognosis. In the present study, c-KIT messenger RNA (mRNA) expression was measured in canine MCTs and its relationship with tumor grade, immunohistochemical staining pattern, post-surgical prognosis, and mutations was investigated. A significant increase of c-KIT mRNA was observed in MCTs versus healthy skin and surgical margins. Mutations were observed in 8.3% of cases. The KIT staining pattern was investigated for both grading systems. In particular, staining pattern III was associated with grade II (G2) and G3 MCTs, while staining patterns I and II were associated with G1 and G2 MCTs. Considering the 2-tier histological grading, the high grade was mainly associated with pattern III (71%) while the low grade was associated with patterns II (70%) and I (28%). A weak association between the KIT staining pattern and outcome was also observed. The results obtained suggest that c-KIT mRNA is overexpressed in canine MCT, although the fold variations were not associated with the protein localization or complementary DNA mutations. These observations suggested that the 3 events were independent. The histological grading and the KIT staining pattern have prognostic value as previously published. Staining pattern I could be especially helpful in predicting a good prognosis of G2 MCTs. Sequence mutations were not necessarily suggestive of a worse prognosis, but might be useful in choosing a chemotherapy protocol.

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Variation among Pathologists in Histologic Grading of Canine Cutaneous Mast Cell Tumors

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870501700305 ◽

2005 ◽

Vol 17 (3) ◽

pp. 245-248 ◽

Cited By ~ 42

Author(s):

Nicole C. Northrup ◽

Barry G. Harmon ◽

Tracy L. Gieger ◽

Cathy A. Brown ◽

K. Paige Carmichael ◽

...

Keyword(s):

Mast Cell ◽

Significant Variation ◽

Low Grade ◽

Histologic Grading ◽

Mast Cell Tumors ◽

Cutaneous Mast Cell ◽

Mitotic Figures

Ten veterinary pathologists at 1 veterinary institution independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors (MCTs). There was significant variation among pathologists in grading the MCTs ( P < 0.001). The probability of assigning a low grade was significantly higher for the pathologists in this study who use a published reference for histologic grading of canine cutaneous MCTs that allows subcutaneous MCTs or MCTs with mitotic figures to be included in the low-grade category ( P < 0.0001 and P < 0.0001, respectively).

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