Table 2.
Key histopathologic features of high-grade uterine mesenchymal tumors
| Sample ID | Sample location | Sample type | Original pathologic diagnosis | Size (mm) | Edge | Cytoarchitecture | Nuclear pleomorphism | Necrosis | TMR | LVI | Sclerosis | Pericytomatous vasculature | Other findings |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UMT01 | Soft tissue | Recurrence | High-grade sarcoma, consistent with malignant PEComa | 155 | NA | E (nested and corded) | ++ | CTN | 20 | Yes | Yes | Nested & corded arrangements of epithelioid cells with variable amphophilic to clear cytoplasm | |
| UMT02 | Lung | Recurrence | Malignant PEComa | 120 | I | S+E | +++ | INF | 34 | Yes | Yes | Yes | S+E cells in sheets and vague fascicles associated; marked nuclear pleomorphism incl MNGCs |
| UMT03 | Uterus | Uterus | Malignant epithelioid neoplasm with smooth muscle differentiation, most consistent with malignant PEComa; differential diagnosis includes epithelioid LMS | 50 | C | S+E | +++ | No | 5 | Yes | Vague nodules of predominantly epithelioid cells forming a nodular deposit in myometrium | ||
| UMT04 | Uterus | Uterus | Malignant myogenic neoplasm, favor LMS (on morphology); differential diagnosis of PEComa based on IHC showing rare HMB45+ | 45 | I | S + focally E | ++ | CTN | 5 | No | Yes | Yes | Spindled areas show tight fascicular arrangements; Epithelioid areas are small nodules admixed with the spindled areas |
| UMT05 | Peritoneum | Recurrence | Hybrid LMS/PEComa (primary tumor); recurrence seems to be predominantly epithelioid PEComa component | 170 | I | E+S | +++B | CTN | 30 | Yes | Sheets of highly pleomorphic S+E cells; recurrence showed more marked pleomorphism; Uterine tumor originally called LMS, but revised to hybrid LMS/PEComa after review of recurrence | ||
| UMT06 | Uterus | Uterus | Endometrial curettage: LMS with epithelioid features; Hysterectomy: malignant PEComa (based on focal HMB45+/MelanA+) | 30 | I | E+S | +++ | No | 10 | No | Biphasic tumor including fascicular spindle cell areas with moderate nuclear grade; focal areas composed of large spindle/epithelioid cells with marked nuclear pleomorphism and nodular areas composed of small epithelioid cells with moderate nuclear grade | ||
| UMT06-R | Peritoneum | Recurrence | Malignant PEComa | 60 | NA | E | +++ | CTN | 38 | No | Sheets and nodules of epithelioid cells with amphophilic or clear cytoplasm | ||
| UMT07 | Soft tissue | Recurrence | Malignant PEComa | 80 | I (focally) | E | +++ | CTN | 18 | No | Yes | Large epithelioid cells with abundant clear cytoplasm arranged in large nests/nodules separated by broad collagenous septa | |
| UMT08 | Pelvis | Recurrence | Malignant PEComa | 62 | I (focally) | S+E | +++B | No | 10 | No | Yes | Whorling fascicles of spindle and focally epithelioid cells | |
| UMT09 | Uterus | Uterus | High grade sarcoma with epithelioid features and myogenic differentiation, favor malignant PEComa | 45 | I | E (round cell) | +++ | CTN | 14 | Yes | Yes | Markedly corded appearance, with cords of epithelioid cells separated by bands of hyalinized collagen | |
| UMT09-R | Lung (core biopsy) | Recurrence | Malignant PEComa | NA | NA | E (round cell) | + | No | 12 | No | Yes | Cords and some nests of epithelioid cells separated by densely hyalinized stromal septa | |
| UMT10 | Uterus | Uterus | High grade sarcoma, favor malignant PEComa | 38 | NA | S+E | +++ | NA | 34 | No | |||
| UMT11 | Uterus | Uterus | High grade spindle and pleomorphic neoplasm, consistent with malignant PEComa | 105 | NA | S+E | +++ | CTN | High | Yes | |||
| UMT12 | Peritoneum | Recurrence | Uterine tumor: PEComa with extensive smooth muscle differentiation versus LMS (former favored after review of recurrence showing MITF+ and rare HMB45+) | 55 | C | S | ++ | CTN | 5 | No | Wide range of morphologic appearances: some areas showed bland appearing storiform fascicles of spindle cells; other areas showed much greater cellularity and nuclear atypia; still other areas composed of spindled and rare epithelioid cells with some clear cell change | ||
| UMT13 | Uterus | Uterus | Malignant PEComa | 240 | I | E+S | +++ | CTN | 10 | Yes | Yes | Spindled and epithelioid cells with eosinophilic and clear cytoplasm | |
| UMT14 | Uterus | Uterus | PEComa, with features indicative of intermediate to aggressive clinical behavior | 90 | NA | S | ++B | No | 11 | No | Scattered pleomorphic cells | ||
| UMT15 | Liver (core biopsy) | Recurrence | Malignant epithelioid neoplasm consistent with malignant PEComa | NA | NA | E | +++B | CTN | 25 | Yes | Sheets of highly pleomorphic epithelioid cells with eosinophilic cytoplasm |
NA – not assessable; TMR – tumor mitotic rate per 10 high-power fields; LVI – Lymphovascular invasion; I – irregular; C – relatively circumscribed; E – epithelioid cells; S – spindle cells; CTN – coagulative tumor necrosis; INF – infarction; Nuclear pleomorphism: + - low, ++ - moderate; +++ - marked, B - bizarre/giant cells; LMS – leiomyosarcoma; IHC – immunohistochemistry