Frozen section examination of adenocarcinomas with poorly cohesive growth, including signet-ring cell carcinoma, is challenging. Due to their diffuse morphology, the tumor cells may be indistinct and difficult to distinguish from inflammatory or stromal cells. Misdiagnosis may result in significant adverse clinical outcome. We performed a detailed retrospective analysis of such cases to identify features that are helpful to avoid misdiagnosis at the time of frozen section. We reviewed the original frozen section slides from 50 patients with poorly cohesive carcinoma (PCC) including 32 with positive and 18 with negative frozen section slides. Tumor cells and inflammatory cells were evaluated for 17 distinct cytologic and nine architectural or stromal features. Features with 100% specificity and positive predictive value (PPV) for carcinoma included the presence of cells with a single distinct cytoplasmic mucin vacuole, focal gland formation, and perineural invasion. Features with high specificity, sensitivity, PPV, and negative predictive value (NPV) (all > 75%) included irregular nuclear contours, large nuclear size with many nuclei > 4× the size of a small lymphocyte, and disruption/obliteration of normal structures. Other features with high specificity and PPV (both ≥ 85%) but relatively low sensitivity and NPV-included crescent-shaped/indented nuclei, prominent nucleoli, anisonucleosis (> 4:1 difference in nuclear size), multinucleation, and the presence of mitotic figures. We characterized useful histologic features of poorly cohesive carcinoma that may serve to distinguish carcinoma cells from benign inflammatory or stroma cells. Knowledge of the relatively specific features in particular may help surgical pathologists avoid false-negative interpretation resulting in significant clinical morbidity.

具有凝聚力差的腺癌的冷冻切片检查，包括印戒细胞癌，具有挑战性。由于它们的扩散形态，肿瘤细胞可能不清楚并且难以与炎性或基质细胞区分开。误诊可能导致严重的不良临床结果。我们对这种情况进行了详细的回顾性分析，以找出有助于避免冷冻切片时误诊的特征。我们回顾了来自50例凝聚力较弱的癌（PCC）患者的原始冷冻切片玻片，包括32例阳性和18例阴性冰冻切片。评估了肿瘤细胞和炎性细胞的17种不同细胞学特征和9种结构或基质特征。具有100％特异性和阳性预测值（PPV）的癌变特征包括细胞存在单个明显的胞浆粘液液泡，局灶性腺体形成和神经周浸润。具有高特异性，敏感性，PPV和阴性预测值（NPV）（均> 75％）的特征包括不规则的核轮廓，大核尺寸和许多核>小淋巴细胞尺寸的4倍以及正常结构的破坏/消除。其他具有高特异性和PPV（均≥85％）但灵敏度较低且NPV包括新月形/锯齿状核，突出核仁，异核病（核大小差异> 4：1），多核和有丝分裂的特征数字。我们表征了凝聚力差的癌的有用的组织学特征，可能有助于区分癌细胞与良性炎症或基质细胞。对相对特定特征的了解尤其可以帮助手术病理学家避免假阴性解释，从而导致明显的临床发病率。