Basaloid squamous carcinoma of the hypopharynx with unususal histologic findings-glandular and spindle cell differentiations

초록

basaloid squamous carcinoma (BSC), first described by Wain et al . at 1986, is a rare variant of squamous cell carcinoma(SCC) with distinct morphologic and biologic features. BSC is composed of a dual population of malignant basaloid cells and squamous cell. The basaloid component consist of smooth contoured lobules with comedo necrosis , solid masses with microcystic space, cord of cells. Mitoses, peripheral nuclear palisading and storoma hyalinosis are frequently found. The squamous components reveal high dysplasia and carcinoma in situ of the overlying mucosa and/or area of invasive SCC. BSC shos high metastatic rate of cervical lymph node and distinct organs. Also the mortality rate of BSC is higher tha usual SCC and adenoid cystic carcinoma (ACC). Differential diagnosis in small sized biopsy specimen included ACC, usual SCC and small cell undifferentiated carcinoma. We expreienced a case of BSC of hypopharynx of 48 yeal old man who had smoking and alcholoic history. His chief complaints were voice change, dysphagia and dyspnea during one month. CT finding revealed a polypoid mass located at supraglottic area along the aryepigottic fold. the resection mass, measuring 2.7x2.5x2.0cm, revealed polypoid appearance with white tan solid cut surface. There were no hemorrhage or necrosis. Histologic feature was same to previously mentioned finding of BSC, as unusual findings, there were glandular differentiation in tumor lobule and spindle cell differentiation in adjacent stroma. The spindle cell showed pleomorphism and positive reaction to CAM 5.2 supporting an epithelial origin. Wein et al supported that a malignant change in a pleuripotent parent cell lead to the biphasic proliferative pattern characteristic of BSC.