本院的個案安妮是一隻已節育的母瑪爾濟斯犬，初次就診時為8歲。安妮患有嚴重的牙周病(periodontal disease)，導致掉牙、牙齦與齒槽骨萎縮，飼主帶安妮至本院進行全口洗牙與牙周治療。治療的過程中發現狗的右側上顎門齒與犬齒之間(103~104)有一個異常增生的腫塊，考量到口腔健康不佳有可能會導致口腔腫瘤產生，建議飼主將腫塊做組織病理學(histopathology)檢查。

    檢查的結果發現安妮口腔的腫塊為「鱗狀上皮細胞癌(squamous cell carcinoma, SCC)」，是狗最常見的口腔癌腫瘤之一。考量到安妮的腫瘤屬於危險性較低的第1級(Grade 1, G1)、也沒有侵犯到週邊正常組織的現象，先不進行大範圍的口腔顏面切除手術，但提醒飼主需要定期回診追蹤，確保腫瘤沒有再生，並且要每天要確實刷牙，維持良好的口腔衛生。
    口腔衛生不佳可能會造成口腔癌發生，可參考本院陳重威獸醫師的文章連結：https://www.hellopeter.com.tw/content-142.html

    本病例中，安妮非常幸運，在腫瘤生成的早期，也就是第1級 (Grade 1, G) 的時候就發現，而且腫瘤發現的部位是在口腔的上顎前端，預後通常比在口腔後端的腫瘤較佳，所以不需要大範圍切除腫瘤週邊的健康組織，手術後的癒合狀況也相當良好。

    術後7個月瑪爾濟斯犬安妮回診，腫塊切除處的牙齦癒合正常、沒有新的腫塊產生，飼主很高興可以不需要做大範圍的切除，未來本院會持續追蹤，確保安妮可以維持良好的口腔健康。

✅鱗狀上皮細胞癌(SCC)是狗貓最常見的口腔癌症，以貓咪發生的比例最高，佔比約64~75%，在狗狗則佔口腔癌症的24~30%，僅次於惡性黑色素瘤(malignant melanoma，約佔30~40%)，是臨床上常見的口腔惡性腫瘤之一。

✅鱗狀上皮細胞癌(SCC)的轉移率不高，但是對於週邊組織的侵犯性相當大，可能破壞的組織包含牙齦、口腔黏膜、舌頭、扁桃腺、齒槽骨及牙齒，甚至可能造成病理性骨折，所以一旦需要手術治療，通常切除的範圍會相當大(至少要切除腫瘤週邊1.5~3公分的正常組織)，連軟組織下面的骨頭都需要切除，還需要搭配化療、放療等療法同時進行，才能確實將腫瘤清除乾淨 (Niemiec et al., 2020，參考文獻2)。而腫瘤的手術療程可能會對顏面結構造成很大的破壞，後續的顏面重建手術也是一大工程，對於狗貓的身體與飼主的照護上，是非常大的負擔。

✅因口腔癌細胞容易轉移擴散，治療口腔癌症單只有化療或放療效果不佳，一定要以口腔外科手術為主。

✅鱗狀上皮細胞癌(SCC)的分級如下 (National Cancer Institute (NCI), 2021，參考文獻1)：
第X級 (Grade X, Gx)：無法評估分化程度 (無法評估惡性程度)
第1級 (Grade 1, G1)：分化良好 (低度惡性)
第2級 (Grade 2, G2)：中度分化 (中度惡性)
第3級 (Grade 3, G3)：分化不良 (高度惡性)
第4級 (Grade 4, G4)：未分化 (極高度惡性)
分級數字越高，代表腫瘤的分化狀況越差、更為惡性，同時腫瘤也有更高的機率轉移至其他器官，治療的效果自然也越差。

    飼主平常可以觀察家中狗貓是否有流口水變多、吞嚥進食困難、體重下降、口腔出血等症狀，若有的話，建議盡快就醫做檢查，及早發現及早治療。

    更多本院牙科和口腔外科治癒的案例分享，請按：https://www.hellopeter.com.tw/contents-2.html

參考文獻：
1. National Cancer Institute (NCI). (2021). Tumor Grade [Online forum comment]. Retrieved from: https://www.cancer.gov/about-cancer/diagnosis-staging/diagnosis/tumor-grade
2. Niemiec B., Gawor J., Nemec A., Clarke D., Tutt C., Gioso M., Stegall P., Chandler M., Morgenegg G., Jouppi R., & Stewart K. (2020). World Small Animal Veterinary Association Global Dental Guidelines. Journal of Small Animal Practice. 2020; 61: E86-E87.

【Severe periodontal disease causing squamous cell carcinoma in a Maltese dog's oral cavity.】

Our patient, Annie, is an 8-year-old spayed female Maltese dog. Annie suffers from severe periodontal disease, leading to tooth loss, gingival recession, and alveolar bone loss. The owner brought Annie to our hospital for dental scaling and periodontal treatment. During the treatment, a mass was found between the right maxillary incisor and canine (103~104) of the dog. Considering the poor oral health might lead to oral tumor formation, the owner was advised to have the growth undergo histopathological examination.

The examination revealed the growth in Annie's oral cavity to be squamous cell carcinoma (SCC), one of the most common oral malignant tumors in dogs. Since Annie's tumor was classified as a low-risk Grade 1 (G1) and showed no invasion into surrounding normal tissues, extensive maxillofacial surgery was not performed subsequently. However, the owner was reminded to schedule regular follow-up visits to ensure the tumor did not recur and to brush Annie's teeth daily to maintain good oral hygiene.
Poor oral hygiene can lead to oral cancer; you can refer to Dr. Chung-Wei Chen's article in our hospital: https://www.hellopeter.com.tw/content-142.html

In this case, Annie was fortunate to have the tumor detected early, at Grade 1 (G), and the location of the tumor in the anterior maxilla usually has a better prognosis than tumors in the posterior oral cavity. Therefore, extensive excision of healthy tissue around the tumor was unnecessary. Post-operative healing was also excellent.

Seven months after surgery, Annie, the Maltese dog, returned for a check-up. The gum at the site of tumor removal healed normally, and no new growths were observed. The owner was pleased that extensive excision was not required. We will continue to monitor Annie to ensure the maintenance of her oral health.

Squamous cell carcinoma (SCC) is the most common oral cancer in dogs and cats, with cats having the highest incidence, accounting for 64-75% of all oral cancer cases, and dogs accounting for 24-30% of oral cancer cases, second only to malignant melanoma (approximately 30-40%). It is one of the common oral malignant tumors seen in clinical practice.

Although SCC has a low metastatic rate, it exhibits significant invasiveness to surrounding tissues, potentially damaging gingiva, oral mucosa, tongue, tonsils, alveolar bone, and teeth, and may even cause pathological fractures. Therefore, surgical treatment usually involves extensive excision (at least 1.5-3 cm of normal tissue around the tumor), including removal of underlying bone, and may require concurrent chemotherapy, radiotherapy, etc., to ensure thorough tumor removal (Niemiec et al., 2020, Reference 2). The surgical course of treating the tumor may cause significant damage to facial structures, and subsequent facial reconstruction surgery is also a major undertaking, posing a significant burden on the pet's body and owner's care.

Due to the tendency of oral cancer cells to metastasize and invade surrounding tissues, treatment with chemotherapy or radiotherapy alone yields poor results; surgical excision is essential.

The grading of SCC is as follows (National Cancer Institute (NCI), 2021, Reference 1):
Grade X (Gx): Grade cannot be assessed (undetermined grade)
Grade 1 (G1): Well differentiated (low grade)
Grade 2 (G2): Moderately differentiated (intermediate grade)
Grade 3 (G3): Poorly differentiated (high grade)
Grade 4 (G4): Undifferentiated (high grade)
A higher grade indicates poorer tumor differentiation, increased malignancy, and a higher probability of metastasis to other organs, resulting in poorer treatment outcomes.

Owners can observe if their dogs or cats experience such as increased drooling, difficulty swallowing, weight loss, oral bleeding, etc. If so, prompt medical examination is recommended for early detection and treatment.

For more cases of successful dental and oral surgery treatments in our hospital, please refer to: https://www.hellopeter.com.tw/contents-2.html

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