The morphological distinction between the various types of mucinous ovarian tumors has major prognostic implications but may be challenging. The aims of our study were to describe inter-observer reproducibility in the morphological diagnosis of mucinous ovarian tumors, to evaluate the clinical relevance of possible diagnostic discrepancies, and to identify molecular abnormalities correlated with the histological type. Seventy-nine ovarian mucinous borderline tumors (MOB) and either expansile or infiltrative carcinomas (MOC) were independently reviewed by two gynecological pathologists. Molecular analysis was performed in 32 cases. Concordance between the two pathologists was reached in 67 cases (k: 0.78). The main discrepancies (8/12) were the evaluation of nuclear grade 3 or that of microfoci (< 5 mm) of infiltrative-type carcinoma in an otherwise typical expansile MOC. Our follow-up analysis showed that infiltrative MOC had a lower overall survival (OS) (p < 0.0024) and progression-free survival (PFS) (p = 0.0060) as compared with MOB and expansile MOC. The presence of nuclear grade 3 or microfoci (< 5 mm) of infiltrative-type pattern of invasion in an otherwise typical expansile MOC did not alter the prognosis as compared with expansile MOC without these features, in terms of OS (p < 0.0028) and PFS (p = 0.0074). KRAS mutations were more frequent in MOB (71%), than in expansile (50%) and infiltrative MOC (14%). In contrast, the prevalence of TP53 mutation was lower in MOB (43%), than in expansile (58%) and infiltrative MOC (71%). Our results confirm that in MOC, the expansile pattern of invasion is associated with a better prognosis than extensive (> 5 mm) infiltrative-type pattern of invasion. No specific or sensitive molecular profile might help in the differential diagnosis of mucinous ovarian tumors.

各种类型的粘液性卵巢肿瘤之间的形态学区别具有重要的预后意义，但可能具有挑战性。我们研究的目的是描述粘液性卵巢肿瘤的形态学诊断中观察者间的可重复性，评估可能的诊断差异的临床相关性，并确定与组织学类型相关的分子异常。两名妇科病理学家对79例卵巢粘液性交界性肿瘤（MOB）和扩张性或浸润性癌（MOC）进行了独立审查。进行了32例分子分析。两名病理学家之间的一致性达到了67例（k：0.78）。主要差异（8/12）是在其他典型的可扩张MOC中评估浸润型癌的3级核或微灶（<5 mm）的评估。我们的后续分析表明， 与MOB和扩张型MOC相比，浸润性MOC的总生存期（OS）（p  <0.0024）和无进展生存期（PFS）（p = 0.0060）低。在其他方面典型的扩张性MOC中，与无这些特征的扩张性MOC相比，存在3级核浸润或浸润型浸润型微灶（<5 mm）不会改变预后，就OS而言（p  <0.0028）和PFS（p  = 0.0074）。卡拉斯在MOB（71％）中发生突变的频率高于在扩张型（50％）和浸润性MOC（14％）中发生的频率。相比之下，TP53突变的发生率在MOB（43％）中比在扩张性（58％）和浸润性MOC（71％）中低。我们的结果证实，在MOC中，与广泛的浸润型浸润型浸润相比，浸润的浸润型伴有更好的预后。没有特异性或敏感的分子特征可能有助于粘液性卵巢肿瘤的鉴别诊断。