A case of basaloid squamous cell carcinoma of the floor of the mouth-Estimation of proliferative activity by Ki-67 immunohistochemical staining-

Abstract

Basaloid squamous cell carcinoma was first reported by Wain et al. in 1986 and has recently been designated a variant of squamous cell carcinoma because of its high potential for distant metastasis. We report a case of basaloid squamous cell carcinoma arising in the floor of the mouth in a 74-year-old man. The proliferative activities of this case and another case previously reported by our department were compared with those of 21 cases of poorly differentiated squamous cell carcinoma. The cases of basaloid squamous cell carcinoma showed high reactivity on Ki-67 immunohistochemical staining. This finding reflects the high malignancy of this disease and suggests that Ki-67 immunohistochemical staining is useful for diagnosis. Radiotherapy was very effective against the primary lesion in our two cases, but both had lung metastasis. In our patient, lung lesions were controlled by chemotherapy, but further investigations are needed to establish standard treatment, including systemic chemotherapy.

Basaloid squamous cell carcinoma of the floor of the mouth: A case report with review of the literature

“…The frequency of occurrence is as low as 2%‐5% of all head and neck cancers 6,9 . In this study, we reviewed 27 cases of OBSCC reported in Japan between January 2001 and January 2020 10‐34 (Table 1). According to the present study, the incidence was the highest in those in their 60s, with men accounting for most patients.…”