[Clinicopathologic features of non-keratinizing carcinoma of nasal cavity and paranasal sinus].

OBJECTIVE: To study the clinicopathologic features, immunophenotype, differential diagnosis and prognosis of non-keratinizing carcinoma of nasal cavity and paranasal sinus.

METHODS: Four hundred and forty-one cases of squamous cell carcinoma of the nasal cavity and sinuses diagnosed in Beijing Tongren Hospital from January 2008 to August 2015 were included. Twenty-six cases of non-keratinizing carcinomas were selected. The histopathologic features and the clinicopathologic data of these twenty-six cases were retrospectively analyzed. Immunohistochemistry (two-step EnVision method) was done to evaluate the expression of CK, vimentin, CK5/6, CK7, CK8/18, p16, p53, Ki-67 etc. In situ hybridization was used to detect Epstein-Barr virus mRNA(EBER), and flow-through hybridization was used to evaluate the presence of human papilloma virus (HPV). One of the cases which HPV is positive was detected by HPV in situ hybridization and RNAscope technology.

RESULTS: The mean age for the twenty-six patients (16 males, 10 females) was 51.2 years (range 22 to 79 years). Three patients had a history of inverted papilloma.Microscopically the tumors showed invasive papillary and inverted growth, and formed solid cell nests with different sizes. It was similar to papillary carcinoma of the urinary tract: the nuclei of the tumor were rounded and the nucleolus are clear. Three cases displayed transition between normal epithelium to neoplastic cells; in two cases (2/26), some tumor cells were spindle shaped. Twenty cases (20/20) were strongly positive for CK, p63; 17 cases (17/20) were strongly positive for CK5/6 and three cases (3/20) were focally positive. Sixteen cases were strongly positive for CK8/18 and three cases (3/20) were focally positive and one case was negative. Seven cases (7/20) were strongly positive for CK7 and 13 cases (13/20) were negative. Two cases (2/20) were focally positive for vimentin and eighteen (18/20) cases were negative. One case (1/20) was strongly positive for p16 and nineteen cases (19/20) were negative. Nineteen cases (19/20) were positive for p53 and one case (1/20) was negative. Ki-67 index was >50% in 11 cases. Twenty cases (20/20) were negative for AFP, NUT, S-100 protein, HMB45 and Melan A. One case was positive for HPV (6, 11, 16, 18), as detected by in situ hybridization. The HPV18 mRNA was detected by RNAscope technique. In situ hybridization were negative in all twenty cases. The mean follow-up time of the patients in this group was less than 5 years, and the prognosis needs further observation.

CONCLUSIONS: Non-keratinizing squamous cell carcinoma is a rare neoplasm with distinct morphological characteristics. Its diagnosis is primarily based on the site of lesions and the histological features.Immunohistochemistry staining can aid the diagnosis and differential diagnoses. The tumor may originate from the epithelium of nasal cavity and sinus. This disease has no relation with HPV and EBV infection, and the treatment is primarily surgical excision combined with postoperative radiotherapy.