Nasal chondromesenchymal hamartoma (NCMH) is a rare benign polypoid mesenchymal tumor arising in the nasal cavity and/or paranasal sinuses. Recognizing these sporadic, rare lesions is crucial, as surgical complete removal of the mass is the common treatment approach. This retrospective study analyzed the demographics, symptoms, and imaging data of 9 patients diagnosed with NCMH between January 2017 and June 2023, possibly representing the largest single-center adult case cohort to date. Diagnostic techniques included nasal endoscopy, CT/MRI scan, immunohistological studies, and morphologic comparisons. Pathologic specimens were subjected to Sanger sequencing of exons 24 and 25 of DICER1. The average age of 9 cases was 24.4 years, and the oldest was 55 years. Four of the patients were children, ranging from 1 year old to 11 years old, with an average of 4.5 years. Nasal congestion is the most common registered symptom. Endoscopic findings showed that most patients had smooth pink neoplasms or polypoid masses in the nasal meatus. Radiologic scanning revealed soft-tissue density masses that occupied the nasal cavity. Histologically, the characteristic structure of NCMHs is immature cellular cartilage nodules and mature cartilage nodules distributed in a loose mucoid matrix. Five of the 9 patients had somatic DICER1 missense mutations. Four of the patients with DICER1-mutated NCMH exhibited a p.E1813 missense hotspot mutation. We also report a case of a rare p.P1836H missense mutation. The detected DICER1 somatic mutations provide compelling evidence of an association with the DICER1 tumor family. We emphasize the importance of pathologic consultation and the need for pathologists to accumulate experience in NCMH diagnosis to avoid misdiagnosis.

中文翻译：

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鼻软骨间质错构瘤中 DICER1 的致病性体细胞突变和临床病理特征：九个病例系列。

鼻软骨间质错构瘤（NCMH）是一种罕见的良性息肉样间质肿瘤，发生于鼻腔和/或鼻旁窦。认识到这些零星的罕见病变至关重要，因为手术完全切除肿块是常见的治疗方法。这项回顾性研究分析了 2017 年 1 月至 2023 年 6 月期间诊断为 NCMH 的 9 名患者的人口统计、症状和影像数据，可能代表了迄今为止最大的单中心成人病例队列。诊断技术包括鼻内窥镜检查、CT/MRI 扫描、免疫组织学研究和形态学比较。对病理标本进行 DICER1 外显子 24 和 25 的桑格测序。 9例平均年龄24.4岁，最大年龄55岁。其中4名患者为儿童，年龄1岁至11岁，平均4.5岁。鼻塞是最常见的症状。内镜检查结果显示，大多数患者鼻道内有光滑的粉红色肿瘤或息肉样肿块。放射扫描显示鼻腔内有软组织密度肿块。组织学上，NCMH的特征结构是未成熟的细胞软骨结节和分布在疏松粘液基质中的成熟软骨结节。 9 名患者中有 5 名存在体细胞 DICER1 错义突变。四名 DICER1 突变 NCMH 患者表现出 p.E1813 错义热点突变。我们还报告了一例罕见的 p.P1836H 错义突变。检测到的 DICER1 体细胞突变提供了与 DICER1 肿瘤家族相关的令人信服的证据。我们强调病理会诊的重要性，强调病理医生需要积累NCMH诊断经验，避免误诊。