Liao Che-Chi, Kuo Ying-Ju, Lu Yen-Wen, Shen Ko-Hung, Wey Shiuan-Li, Wang Ren-Ching, Chang Nien-Yi, Hsieh Min-Shu, Chen Yun-An
Department of Pathology, China Medical University Hospital, No. 2, Yude Road, North District, Taichung City, 40402, Taiwan.
Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
Head Neck Pathol. 2025 Jul 14;19(1):87. doi: 10.1007/s12105-025-01825-8.
This study aims to characterize the rare morphological variant of nasopharyngeal carcinoma known as reticular and myxoid nasopharyngeal carcinoma (RMNK-NPC), which poses diagnostic challenges due to its resemblance to salivary gland tumors. We seek to detail its histopathological and immunohistochemical features, clarify differential diagnoses, and evaluate clinical outcomes.
Cases of RMNK-NPC were retrospectively identified from pathology consultation archives and multidisciplinary conference records in Taiwan. Histopathological features, including results of previously performed immunohistochemical stains and Epstein-Barr virus-encoded RNA (EBER) in situ hybridization, were reviewed by three pathologists. Relevant clinical information and imaging findings were collected when available. A literature search was conducted to identify previously reported cases with similar histological features.
The cohort included eight patients (7 males, 1 female; median age 65.5 years). Clinical presentations included advanced-stage tumors with lymph node metastases in seven patients and distant metastasis in two patients. All tumors exhibited myxoid stroma with reticular, trabecular, and cord-like arrangements of epithelioid to spindle cells, with transition to non-keratinizing squamous cell carcinoma (NKSCC) in three cases. Immunohistochemistry showed consistent positivity for pan-cytokeratin and squamous markers, while other myoepithelial markers were mostly negative, except SOX10. EBER ISH showed strong nuclear positivity in most cases, confirming EBV association. Limited follow-up data for four patients who received chemoradiotherapy showed stable disease at 3-4 months in two. The other two patients died at 42 and 108 months, respectively, from unrelated causes, with no recurrence observed.
RMNK-NPC represents an EBV-associated NPC with unique histomorphology that overlaps with salivary gland tumors. Accurate diagnosis relies on comprehensive immunohistochemical panels and EBER ISH. Awareness of this entity is crucial to avoid misdiagnosis and guide appropriate treatment.
本研究旨在描述一种罕见的鼻咽癌形态学变异型，即网状和黏液样鼻咽癌（RMNK-NPC），因其与涎腺肿瘤相似而给诊断带来挑战。我们试图详细阐述其组织病理学和免疫组化特征，明确鉴别诊断，并评估临床结局。
从台湾的病理会诊档案和多学科会议记录中回顾性识别RMNK-NPC病例。由三位病理学家复查组织病理学特征，包括先前进行的免疫组化染色结果和爱泼斯坦-巴尔病毒编码RNA（EBER）原位杂交结果。如有可用信息，收集相关临床资料和影像学检查结果。进行文献检索以识别先前报道的具有相似组织学特征的病例。
该队列包括8例患者（7例男性，1例女性；中位年龄65.5岁）。临床表现包括7例患者为晚期肿瘤伴淋巴结转移，2例患者有远处转移。所有肿瘤均表现为黏液样间质，上皮样至梭形细胞呈网状、小梁状和索状排列，3例转变为非角化性鳞状细胞癌（NKSCC）。免疫组化显示全细胞角蛋白和鳞状标志物呈一致性阳性，而其他肌上皮标志物大多为阴性，但SOX10除外。EBER原位杂交在大多数病例中显示强核阳性，证实与EB病毒有关。4例接受放化疗患者的随访数据有限，其中2例在3至4个月时病情稳定。另外2例患者分别在42个月和108个月时死于无关原因，未观察到复发。
RMNK-NPC是一种与EB病毒相关的鼻咽癌，具有与涎腺肿瘤重叠的独特组织形态学。准确诊断依赖于全面的免疫组化检测和EBER原位杂交。认识这一实体对于避免误诊和指导恰当治疗至关重要。
