Objective: To study the clinicopathological features, diagnostic features and differential diagnoses of SMARCB1 (INI1)-deficient sinonasal carcinoma (SDSC). Methods: Six cases of SDSC diagnosed at Eye, Ear, Nose and Throat Hospital, Fudan University from 2016 to 2018 were retrieved; the clinical features, histomorphology, immunophenotype, radiology and outcome were analyzed with review of literature. Results: There were five men and one woman with age range of 37 years to 75 years (mean 56 years). One case was in stage T2, and 5 cases were in stage T4. Computer tomography and magnetic resonance imaging showed a mass occupying the sinonasal cavity with bone destruction in all six patients. Microscopically, the tumors had infiltrative margins. Four tumors were composed mostly of basaloid cells, which possessed high nuclear/cytoplasmic ratio,scant cytoplasm,and minimalnuclear pleomorphism; and the cells were arranged in sheets or nests in a desmoplastic stroma. Two tumors were composed of rhabdoid cells, which possessed abundant, eosinophilic cytoplasm and eccentric nuclei, often growing in a nests or sheets pattern. Immunohistochemical staining showed that 6/6 cases had complete loss of INI1, diffusely and strongly positive for CKpan, and were negative for S-100 and EBER ISH; 4/6 cases were focally positive for p63; 1/5 was focally positive for Syn and p16. The Ki-67 index was 30% to 70%. The follow-up period ranged 1-26 months, with one patient died of extensive metastases, one had local recurrence, and two had lymph node metastases; one was alive without disease, and one was lost to follow-up. Conclusions SMARCB1 (INI1)-deficient sinonasal carcinoma is mostly aggressive, with rapid progression and poor prognosis. Histomorphological spectrum predominantly consists of basaloid type and rhabdoid type. The complete loss of nuclear expression of INI1 can help to distinguish this tumor from its many mimickers.

Objective:To investigate the clinicopathological features, immunophenotype, differential diagnosis and prognosis of sinonasal renal cell-like adenocarcinoma.Methods:Retrospective analysis was performed on the cases of sinonasal carcinoma from August 2014 to December 2018 at Eye, Ear, Nose and Throat Hospital, Fudan University. Renal cell-like adenocarcinoma was screened for clinicopathologic feature analysis, and relevant literatures were reviewed.Results:There were 460 cases of sinonasal carcinoma, among which 70 cases (15.2%) were adenocarcinoma, with five (1.1%) being renal cell-like adenocarcinomas. Four patients were male and one was female, with a mean age of 46.5 years (range 29-52 years). The main clinical manifestations were nasal obstruction and epistasis. A red polypoid mass was found under nasal endoscopy. Imaging showed nasal cavity and ethmoid sinus mass with invasion into surrounding structures and bone destruction. Microscopically, the tumor cells were arranged in nests, alveoli and microcapsules with abundant intervening capillaries, accompanied by hemorrhage. The cytoplasm of the cells was clear with low nuclear grade, and the nucleoli were inconspicuous. In some areas, the tumor invaded bone tissue. Immunohistochemical markers CKpan, CK7, CAⅨ, S-100 and vimentin were positive, with low Ki-67 proliferation index. RCC, CD10, PAX8, p63, SMA, HHF35, Calponin, CD117, TTF-1 and neuroendocrine markers Syn and CHG were all negative. EWSR1 and ETV6 gene rearrangements were not detected by FISH. All five patients underwent surgical resection after initial diagnosis. One patient underwent surgical resection after second recurrence and adjuvant radiotherapy, one patient received postoperative radiotherapy, one patient underwent surgical resection after recurrence, one patient had no recurrence and one patient received radiotherapy after recurrence. All five patients had no distant metastasis and survived without tumor up to December 2019.Conclusions:Primary sinonasal renal cell-like adenocarcinoma is a special subtype of low-grade non intestinal adenocarcinoma, with low incidence and inert biologic behavior. At present, most of the literatures are case reports. Before a diagnosis is made, other primary and metastatic clear cell tumors need to be excluded. Immunohistochemistry is helpful for diagnosis and differential diagnosis. Surgical resection is the mainstay of treatment, and may be supplemented by radiotherapy.

Objective:To investigate the clinicopathologic features, immunophenotype, molecular genetic changes of ETV6-rearranged low-grade sinonasal non-intestinal-type adenocarcinoma (ETV6-RLGSNAC).Methods:Primary sinonasal epithelial malignant tumors were collected from January 2015 to January 2020 in the Department of Pathology, Eye, Ear, Nose and Throat Hospital affiliated to Fudan University. Through morphological observation, immunohistochemical detection and fluorescence in situ hybridization (FISH), ETV6-RLGSNAC was screened out for clinicopathological feature analysis, and relevant literatures were reviewed.Results:There were 550 cases of primary sinonasal epithelial malignant tumors, among which 82 cases were adenocarcinoma. There were 29 cases of low-grade non-intestinal adenocarcinoma, only 3 cases of ETV6-RLGSNAC were screened out. Of the 3 patients, 2 cases were male and 1 case was female, with a mean age of 54 years (range 37-64 years). The main clinical manifestations were nasal stenosis, nasal obstruction and epistaxis. A neoplasm with smooth surfaces was observed under nasal endoscopy. Imaging showed an expansive mass in the sinonasal area. Gross examination showed gray-yellow cut surface with firm texture and a maximum diameter of 2-3 cm. Microscopically, tumors were non-encapsulated and well-circumscribed with expansive growth pattern. The tumor cells were small and mild, cylindrical and cuboidal, and arranged in regular glandular and trabecular patterns. The cytoplasm was eosinophilic and the nuclei were basally located with inconspicuous nucleoli. By immunohistochemistry (IHC), CK7, SOX-10, DOG1 and vimentin were positive and S-100 expressed in small clusters of cells in all cases. GCDFP-15, CD56, CK20, mammaglobin, TTF-1, NR4A3 were all negative. The Ki-67 value-added index of all cases was low (<5%). ETV6 gene rearrangement was confirmed in all the cases by FISH, and two cases had NTRK3 gene rearrangement. All three patients underwent radical resection after diagnosis, and one also had adjuvant radiotherapy. All three patients were available with a follow-up time of 12-25 months, and all were recurrence free.Conclusions:ETV6-RLGSNAC is a rare low-grade and newly named non-intestinal adenocarcinoma. The histomorphology is similar to other low-grade nasal sinonasal adenocarcinomas and some salivary gland tumors. IHC and FISH are useful for the diagnosis and differential diagnosis.