Mutations of the c-KIT gene in canine mast cell tumors and respective nodal metastases classified according to mast cell infiltration / Mutações no gene c-KIT em mastocitomas caninos e respectivas metástases nodais classificados segundo a infiltração de mastócitos

The molecular background of canine mast cell tumors (MCT) has been extensively investigated; however, the dynamic molecular changes that occur during carcinogenesis and metastasis are not fully understood. This study aimed to evaluate the incidence of mutations in the c-KIT proto-oncogene in canine MCTs and relative draining regional lymph nodes. Suspected or confirmed lymph node metastasis was classified accordingly to the HN Weishaar classification. The study included 34 dogs diagnosed with MCT; 19 patients were enrolled prospectively. These dogs had the primary MCT and regional lymph node resected and analyzed simultaneously. The second group was evaluated retrospectively and included fifteen patients resectioning the primary MCT without evaluation of regional lymph node. Analyzes of c-KIT mutation were performed for all primary MCTs and, in the first group, compared between primary MCT and HN-classified metastasis. Internal tandem duplications (ITD) in exon 11 of the c-KIT gene were detected in 20% of patients. Ten of the nineteen patients (52%) in the first group presented mast cell infiltration in the regional lymph node, and ITD in exon 11 of the c-KIT gene was detected in five and two dogs from Groups 1 and 2, respectively. ITD c-KIT mutations are common in canine MCT and may be found in the draining lymph node metastases/mast cell infiltrates in the absence of mutation of the primary tumor. Evaluation of c-KIT mutation in the primary tumor and metastases may be informative for defining both prognosis and therapeutic options in MCT cases.

O perfil molecular do mastocitoma (MCT) tem sido bastante investigado, no entanto as dinâmicas moleculares que ocorrem durante a carcinogênese e metástase desta neoplasia não estão bem esclarecidas. O objetivo desse estudo foi avaliar a incidência de mutações no proto-oncogene c-KIT em MCTs caninos e respectivos linfonodos regionais. Os casos suspeitos ou confirmados de metástase para os linfonodos, foram classificados de acordo com a classificação HN de Weishaar. O estudo incluiu 34 cães diagnosticados com MCT e, desses, 19 pacientes foram avaliados de maneira prospectiva, em que o tumor primário e o linfonodo regional foram ressecados e analisados simultaneamente. O segundo grupo foi avaliado retrospectivamente e incluiu quinze pacientes que tiveram ressecção do MCT primário sem avaliação de linfonodo regional. A análise da mutação c-KIT foi realizada para todos os MCTs primários e, no primeiro grupo, comparados entre MCT primário e metástase classificada pelo sistema HN. Duplicações internas em tandem (DIT), no exon 11 do gene c-KIT, foram detectadas em um total de 20% dos pacientes. Dez dos dezenove pacientes (52%) do primeiro grupo apresentavam infiltração de mastócitos no linfonodo regional, e DIT no exon 11 do gene c-KIT foram identificadas em cinco e dois cães dos Grupos 1 e 2, respectivamente. Mutações do tipo DIT no gene c-KIT são comuns no MCT canino e podem estar presentes nas metástases/infiltrados de mastócitos na ausência de mutação do tumor primário. A avaliação da mutação no gene c-KIT no tumor primário e metástases pode ser informativa para definir tanto o prognóstico quanto as opções terapêuticas em casos de MCT.

Dysgerminoma and granulosa cell tumor in a bitch

Dysgerminoma and granulosa cell tumor are neoplasms of the ovary of domestic animals, originating from germ cells and sex-cords cells, respectively. These neoplasms generally occur unilaterally, and usually as a single neoplasm. This report describes a case of a dysgerminoma in the right ovary and a granulosa cell tumor in the left ovary in a six years old bitch. An Akita and Siberian Husky crossbred bitch was admitted at the Veterinary Hospital (Universidade Vila Velha), with a history of purulent vaginal discharge, irregular estrous cycle, fatigue, polydipsia and polyuria. Ultrasound exam demonstrated bilateral ovarian neoplasms, and the animal was subjected to ovariohysterectomy. Macroscopic and microscopic features found in right and left ovaries were typical of dysgerminoma and granulosa cells tumor Sertoli-like, respectively. The uterus had cystic endometrial hyperplasia associated with mild metritis. Ovarian neoplasms occurring bilaterally are uncommon especially with different cell origins and distinct histopathological patterns in each ovary as described in this report.

Dysgerminoma and granulosa cell tumor in a bitch

Dysgerminoma and granulosa cell tumor are neoplasms of the ovary of domestic animals, originating from germ cells and sex-cords cells, respectively. These neoplasms generally occur unilaterally, and usually as a single neoplasm. This report describes a case of a dysgerminoma in the right ovary and a granulosa cell tumor in the left ovary in a six years old bitch. An Akita and Siberian Husky crossbred bitch was admitted at the Veterinary Hospital (Universidade Vila Velha), with a history of purulent vaginal discharge, irregular estrous cycle, fatigue, polydipsia and polyuria. Ultrasound exam demonstrated bilateral ovarian neoplasms, and the animal was subjected to ovariohysterectomy. Macroscopic and microscopic features found in right and left ovaries were typical of dysgerminoma and granulosa cells tumor Sertoli-like, respectively. The uterus had cystic endometrial hyperplasia associated with mild metritis. Ovarian neoplasms occurring bilaterally are uncommon especially with different cell origins and distinct histopathological patterns in each ovary as described in this report.(AU)