Sarcomatoid squamous cell carcinoma of pharynx: A case report with immunohistochemical study

Primary sarcomatoid squamous cell carcinoma (S-SCC) of pharynx is a very rare tumor. A 77-year-old woman presented with sore throat. Laryngoscope revealed an infiltrating tumor of lower pharynx. The tumor was ulcerated and measured 3 cm × 4 cm × 3 cm. The tumor was invasive and involved the surrounding tissues. Biopsies showed sarcomatous malignant spindle cell proliferation as well as invasive well-differentiated squamous cell carcinoma (SCC). The former occupied 80% and the latter 20%. Gradual transitions between malignant spindle cells and SCC were frequently seen. The histological diagnosis was S-SCC. Immunohistochemically (the results are shown in Table 1), the tumor cells were positive for vimentin, cytokeratin (CK) AE1/3, CK CAM5.2, CK WSS, CK KL-1, CK MNF-15, CK5, CK6, CK7, CK8, CK 18, CK19, p53 and Ki67 (labeling index = 65%), but negative for CK34BE12, CK20, EMA, S100 protein, NSE, NCAM, synaptophysin, chromogranin, desmin, α-smooth muscle actin, smooth muscle actin (HHF-35), h-caldemon, CD31, factor VIII-related antigen, CD34, HMB45, KIT, PDGFRA, CA19-9, CEA, bcl-2, CD3, CD20, CD45, CD138, myoglobin, HPV, and EBER. The author’s diagnosis was S-SCC. The patient received chemotherapy and radiation, and is now in complete remission 3 years after the diagnosis.