Malignant epithelioid neoplasm of the ileum with ACTB-GLI1 fusion mimicking an adnexal mass

BACKGROUND: Malignant epithelioid neoplasm with ACTB-GLI1 fusion are considered different from the more common pericytic lesions, such myopericytoma, because they have a spectrum of different genetic abnormalities. They appear to pursue a benign clinical course in young adults, although in sporadic cases lymph node metastasis were described. The categorization of this new type of tumor may also lead to new therapeutic strategies, because they might be sensitive to SHH pathway inhibitors. CASE PRESENTATION: The case involves a 72-years-old multiparous woman who accessed our department after an incidental finding of a right adnexal mass of 43 mm with contrast-enhancement on a control computed tomography scan made for suspected diverticulitis. Our intervention was a detailed ultrasound description of the suspected neoplasm; a diagnostic laparoscopy and the contextual laparotomic removal of abdominal mass; its histological and immunohistochemical analysis. Our main outcome measure is the definition and future recognition of new pathologic entity called malignant epithelioid neoplasm with ACTB-GLI1 fusion. CONCLUSIONS: We described for the first time the ultrasound characteristic of this type of lesion using standardized terminology and we believe that it may be the first step to improve the acknowledgement of this novel pathologic entity defined as malignant epithelioid neoplasm with GLI-1 fusions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12905-022-01679-0.