Canine tongue tumors are uncommon and account for 4% of all oropharyngeal tumors in dogs
SCC is the most common tongue tumor (50%)
White dogs are predisposed to tongue SCC
Grading system based on degree of differentiation, degree of keratinization, mitotic rate, tissue invasion, vascular invasion, pleomorphism, and scirrhous reaction
Other types of tongue tumors include granular cell myoblastoma, malignant melanoma, MCT, FSA, ADC (salivary duct or ectopic thyroid origin), neurofibrosarcoma, leiomyosarcoma, HSA and hemangioma, rhabdomyoma and rhabdomyosarcoma, myxoma, and lipoma
Granular cell myoblastomas are invasive and large
However, local control rate following surgery > 80% and metastasis is rare
Malignant melanoma is associated with a local control rate of 80% and metastatic rate < 50%
54% of canine tongue tumors are located in the midline or bilaterally symmetrical
Non-neoplastic tongue lesions include eosinophilic granuloma (cat) and calcinosis circumscripta (cats and dogs)
+ Diagnosis
Ultrasonography is useful in delineating margins of lingual mass
Wedge incisional biopsy closed with horizontal mattress sutures
Regional lymph node FNA for staging purposes
+ Treatment
Partial glossectomy of 40%-60% tongue if tumor is confined to the lateral or rostral half of the tongue
However, 33%-100% subtotal glossectomy has following either trauma or surgery has been reported in 5 dogs with minimal postoperative problems (ptyalism in 1 dog)
E-tube or G-tube feeding is required postoperatively if > 50% partial glossectomy
± radiation therapy if inoperable or metastatic to the regional lymph nodes
+ Prognosis
Prognosis depends on site, type, and grade of tumor:
MST 16 months for grade I SCC
MST 4 months for grade II SCC
MST 3 months for grade III SCC
Surgery or radiation therapy for 10 dogs with glossal SCC: 12-month survival rate 50% with complete histologic resection and 60%-80% for complete histologic resection with low-grade histology