McHugh Kelsey E, Policarpio-Nicolas Maria Luisa C
Department of Laboratory Medicine, Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio, USA,
Department of Laboratory Medicine, Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio, USA.
Acta Cytol. 2019;63(5):431-437. doi: 10.1159/000500351. Epub 2019 May 27.
SMARCB1 (INI-1)-deficient sinonasal carcinoma is a rare entity within the subgroup of poorly differentiated sinonasal tract carcinomas. As there are only two papers describing the cytologic features of this entity, herein we describe the unique cytomorphologic features of a pulmonary metastasis of this tumor and include the differential diagnosis based on tumor location. The patient was a 53-year-old male who initially presented with sinus congestion and vision changes including left-eye proptosis and diplopia. The initial biopsy of the ethmoid-centered sinonasal mass was non-keratinizing squamous cell carcinoma based on strong immunoreactivity with p40 and absence of immunoreactivity for chromogranin, synaptophysin, p16, and EBER. However, the final diagnosis of the surgical resection was amended to SMARCB1 (INI-1)-deficient sinonasal carcinoma after additional immunohistochemical stains were performed. Post-primary resection, follow-up computed tomography imaging revealed significant interval progression of a solitary, initially indeterminate 1-cm lung nodule in the left upper lobe. Endobronchial ultrasound-guided fine-needle aspiration with concomitant core-needle biopsy was performed. Rapid on site evaluation of cytologic smears revealed a hypercellular specimen consisting of sheets of epithelioid cells with very scant to absent cytoplasm, ill-defined cell borders, enlarged fragile nuclei, and areas of nuclear molding. Mitotic figures were present. Other areas showed tumor cells with spindled to elongated nuclei and scant to ill-defined wispy cytoplasm. Both cytology cell block and core-needle biopsy histopathologic material showed the tumor cells to be negative for INI-1 nuclear staining as well as CK5/6, CAM5.2, p40, p63, CK7, AE1/3, and TTF-1. SMARCB1 (INI-1)-deficient sinonasal carcinoma can have a spectrum of morphologies and may mimic "small-round-blue-cell" and spindle-cell tumors on cytology preparations. Given the pulmonary location of the aspirate, familiarity with the cytomorphologic spectrum of SMARCB1 (INI-1)-deficient sinonasal carcinoma, inclusion of this entity within the differential diagnosis, and performance of immunohistochemistry will aid in arriving at the correct diagnosis.
SMARCB1（INI-1）缺陷型鼻窦癌是低分化鼻窦道癌亚组中的一种罕见实体。由于仅有两篇论文描述了该实体的细胞学特征，在此我们描述了该肿瘤肺转移的独特细胞形态学特征，并包括基于肿瘤位置的鉴别诊断。患者为一名53岁男性，最初表现为鼻窦充血和视力改变，包括左眼突出和复视。以筛窦为中心的鼻窦肿物的初次活检显示为非角化性鳞状细胞癌，这基于其对p40的强免疫反应性以及对嗜铬粒蛋白、突触素、p16和EBER无免疫反应性。然而，在进行了额外的免疫组化染色后，手术切除的最终诊断修正为SMARCB1（INI-1）缺陷型鼻窦癌。原发切除术后，随访计算机断层扫描成像显示左肺上叶一个最初不确定的1厘米孤立肺结节有明显的间隔期进展。进行了支气管内超声引导下细针穿刺并同时进行了粗针活检。对细胞学涂片的快速现场评估显示，标本细胞丰富，由成片的上皮样细胞组成，细胞质极少或无，细胞边界不清，核大且脆弱，有核塑型区域。可见有丝分裂象。其他区域显示肿瘤细胞的核呈梭形至细长形，细胞质稀少至边界不清呈细丝状。细胞学细胞块和粗针活检组织病理学材料均显示肿瘤细胞INI-1核染色以及CK5/6、CAM5.2、p40、p63、CK7、AE1/3和TTF-1均为阴性。SMARCB1（INI-1）缺陷型鼻窦癌可具有一系列形态，在细胞学制片上可能模仿“小圆形蓝细胞”和梭形细胞肿瘤。鉴于穿刺取材来自肺部，熟悉SMARCB1（INI-1）缺陷型鼻窦癌的细胞形态谱、在鉴别诊断中考虑该实体以及进行免疫组化将有助于做出正确诊断。
