Myoepithelioma-like tumor of the vulvar region shows a quiet genome and heterogeneous detectable mechanisms of SMARCB1 inactivation: Integrated analysis of two cases and review of the literature.
Hiroshi Yoshida, Mayumi Kobayashi-Kato, Kouya Shiraishi et al.
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Case in brief
Two cases of myoepithelioma-like tumor of the vulvar region (MELTVR) were analyzed, characterized by uniform epithelioid to spindle cells in myxoid stroma and complete loss of INI1 expression. Genomic profiling revealed low tumor mutation burden and heterogeneous mechanisms of SMARCB1 inactivation, with one case showing a focal homozygous deletion and the other lacking detectable mutations. These findings emphasize the importance of molecular analysis in diagnosis.
What made this case unusual
The tumors exhibited a quiet genomic landscape with low mutation burden and no pathogenic mutations in major cancer-associated genes, which is atypical for neoplasms that mimic malignant sarcomas.
Diagnostic / clinical pearl
Clinicians should consider myoepithelioma-like tumors of the vulvar region in differential diagnoses for vulvar sarcomas, particularly when INI1 loss is observed, and utilize genomic profiling to aid in accurate diagnosis.
Why it matters
Understanding the genomic characteristics of MELTVR can help differentiate it from more aggressive malignancies, potentially preventing unnecessary aggressive treatments.