We report 7 cases of an indolent, variably myxoid tumor of the vocal cords, characterized by overt cellular atypia with large cells containing intranuclear and intracytoplasmic vacuoles, delicate curvilinear vessels, and sparse inflammatory infiltrate. Six patients were male, aged 15 to 65 years, and 1 patient was a 54-year-old female. All tumors were located in the superficial portion of the vocal cord. One patient suffered a recurrence that was completely resected; all patients with available follow-up data currently have no evidence of disease. The tumors contained alternating areas with myxoid stroma and more compacted regions with tumor cells organized in short fascicles, interwoven with delicate curvilinear vasculature. Overt cellular atypia with large cells containing intranuclear and intracytoplasmic vacuoles or resembling ganglion cells was present in all cases but mitoses and necrosis were absent. ALK immunostaining was positive in all cases, while most tumors were negative for smooth muscle actin. Targeted RNA-sequencing revealed an identical TIMP3::ALK fusion with exon 1 of TIMP3 gene being fused with exon 12 of ALK gene in all analyzable cases. For various reasons discussed, it remains unclear whether this tumor represents a mere subtype of IMT or a separate entity. Nevertheless, it is a morphologically distinct and diagnostically challenging lesion that needs to be recognized by surgical pathologists in order to prevent overdiagnosis in this clinically very delicate area.

• Keywords
• Inflammatory myofibroblastic tumor, Larynx, Myxoid fibroblastic tumor, Soft tissues, TIMP3::ALK, Vocal cords,
• MeSH
• Gene Fusion MeSH
• Vocal Cords * MeSH
• Immunohistochemistry MeSH
• Middle Aged MeSH
• Humans MeSH
• Biomarkers, Tumor * genetics   MeSH
• Proteoglycans genetics   MeSH
• Tissue Inhibitor of Metalloproteinase-3 genetics   MeSH
• Receptor Protein-Tyrosine Kinases genetics   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Names of Substances
• Biomarkers, Tumor * MeSH
• Proteoglycans MeSH
• TIMP3 protein, human MeSH Browser
• Tissue Inhibitor of Metalloproteinase-3 MeSH
• Receptor Protein-Tyrosine Kinases MeSH

We report on 51-year-old woman who presented with brown discharge and postcoital bleeding due to myoma nascens-like polypoid mass distending cervical canal. Histologically, the tumor consisted of high-grade spindle cell component with up to 15 mitotic figures per 10 HPF and also low-grade leiomyoma-like areas with focal myxoid change and so far undescribed cytoplasmic signet ring cell change. Immunohistochemically Desmin, actin, and h-caldesmon were negative. Conversely, BCOR positive expression was coupled with Cyclin D1 positivity and was antibody clone dependent. The molecular NGS and FISH study identified reciprocal fusion gene ZC3H7B-BCOR. In conclusion, these findings further support the idea of routine reflex molecular testing of uterine mesenchymal tumors with unusual clinical presentation or in case malignancy is suspected. Lastly, we suggest ZC3H7B-BCOR rearranged high-grade endometrial stromal sarcoma might be considered as a tumor suitable for BCL6-targeted treatment.

• Keywords
• BCOR protein, Endometrial stromal, Female, Fusion, Oncogene proteins, Proto-oncogene proteins, RNA-binding proteins, Repressor proteins, Sarcoma, Signet ring cell, ZC3H7B protein,
• MeSH
• Sarcoma, Endometrial Stromal genetics   pathology   MeSH
• Carcinoma, Signet Ring Cell diagnosis   pathology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Biomarkers, Tumor genetics   MeSH
• Uterine Neoplasms pathology   MeSH
• Endometrial Neoplasms genetics   pathology   MeSH
• RNA-Binding Proteins metabolism   MeSH
• Proto-Oncogene Mas MeSH
• Proto-Oncogene Proteins genetics   metabolism   MeSH
• Repressor Proteins metabolism   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Names of Substances
• BCOR protein, human MeSH Browser
• MAS1 protein, human MeSH Browser
• Biomarkers, Tumor MeSH
• RNA-Binding Proteins MeSH
• Proto-Oncogene Mas MeSH
• Proto-Oncogene Proteins MeSH
• Repressor Proteins MeSH
• ZC3H7B protein, human MeSH Browser