Brentlinger Mikaela N, Padilla Osvaldo, Qiao Jesse
Pathology, Texas Tech University Health Sciences Center Paul L. Foster School of Medicine, El Paso, USA.
Cureus. 2022 Dec 17;14(12):e32634. doi: 10.7759/cureus.32634. eCollection 2022 Dec.
A malignant peripheral neural sheath tumor (MPNST) is a malignant soft tissue neoplasm with cellular origin arising from the outer lining of peripheral nerves. Approximately 10 cases have been identified to date where the lower urinary tract was affected. We discuss the case of a female patient that presented with primary MPNST that arose in the urethral tract in the absence of neurofibromatosis type 1 (NF1) or prior malignancies. This patient presented with pain and acute urinary tract symptoms secondary to urethral obstruction by a protruding vaginal mass. The patient underwent an incomplete initial resection to alleviate symptoms and to obtain a tissue diagnosis. Three months after the first hospitalization, the patient was re-hospitalized due to the recurrence of symptoms and subsequently underwent a complete tumor excision. The initial resection showed a 7.0 x 4.5 x 4.5 cm aggregate of tan-red to gray tumor masses. Microscopic examination showed a spindle cell neoplasm with malignant cytological features (hypercellularity, atypical mitoses, nuclear pleomorphism, and indistinct borders). Tumor cells stained positive for SOX10, S-100 (10% of tumor), with a "mosaic pattern" of H3K27ME3 (50% of tumor nuclei positive). Other lineage-specific and keratin markers stained negative. In the absence of other patient known primaries, the findings were consistent with a primary MPNST of the urinary tract. Residual tumor was identified on MRI scans one month after the follow-up. The completely excised tumor specimen on the second admission showed identical morphology when compared to the first specimen. While MPNSTs typically carry a poor prognosis, knowledge of behavior and prognosis of primary MPNSTs in the bladder is limited, due to the few relative numbers of available case reports. Further research is needed to study the clinical behavior, morphology, immunophenotypes, and genetics of primary MPNSTs arising from the lower urinary tract.
恶性外周神经鞘瘤（MPNST）是一种起源于外周神经外层的恶性软组织肿瘤。迄今为止，已确诊约10例累及下尿路的病例。我们讨论了一名女性患者的病例，该患者患有原发性MPNST，起源于尿道，且不存在1型神经纤维瘤病（NF1）或既往恶性肿瘤病史。该患者因阴道肿物突出导致尿道梗阻，出现疼痛和急性尿路症状。患者接受了不完全的初始切除以缓解症状并获得组织诊断。首次住院三个月后，患者因症状复发再次住院，随后接受了肿瘤完整切除。初始切除显示有一个7.0×4.5×4.5厘米的黄褐色至灰色肿瘤团块。显微镜检查显示为具有恶性细胞学特征（细胞增多、非典型有丝分裂、核多形性和边界不清）的梭形细胞瘤。肿瘤细胞SOX10、S-100染色阳性（10%的肿瘤细胞），H3K27ME3呈“镶嵌模式”（50%的肿瘤细胞核阳性）。其他谱系特异性和角蛋白标记物染色阴性。在没有其他已知原发性肿瘤的情况下，这些发现与尿路原发性MPNST一致。随访一个月后，MRI扫描发现残留肿瘤。第二次入院时完整切除的肿瘤标本与第一个标本相比，形态相同。虽然MPNST通常预后较差，但由于可用病例报告数量相对较少，关于膀胱原发性MPNST的行为和预后的了解有限。需要进一步研究来探讨下尿路原发性MPNST的临床行为、形态、免疫表型和遗传学。
