Details

Autor(en) / Beteiligte

• Mills, Anne M.
• Jenkins, Taylor M.
• Howitt, Brooke E.
• Fan, Jinbo
• Ring, Kari L.
• Cook, Ian

Titel

Mesonephric-like Endometrial Carcinoma: Results From Immunohistochemical Screening of 300 Endometrial Carcinomas and Carcinosarcomas for This Often Overlooked and Potentially Aggressive Entity

Ist Teil von

• The American journal of surgical pathology, 2022-07, Vol.46 (7), p.921-932

Erscheinungsjahr

2022

Beschreibungen/Notizen

• Mesonephric-like endometrial carcinoma is a rare but frequently misclassified and aggressive malignancy. KRAS mutations, limited estrogen receptor (ER) expression, and TTF-1, GATA3, and luminal CD10 expression are described in these tumors, but an immunohistochemistry-based screening approach has not been studied. We assessed 300 endometrial carcinomas/carcinosarcomas to ascertain the specificity of TTF-1/GATA3/luminal CD10 expression with or without ER staining for this diagnosis. Next-generation sequencing and morphologic review were performed on screen-positive cases. In all, 3% (9/300) were TTF-1 + ; 2 coexpressed GATA3. No cases expressed luminal CD10 or GATA3 in isolation. Two TTF-1 + /ER − cases, one of which was also GATA3 + , were reclassified as mesonephric-like based on morphology and molecular results ( KRAS mutations without mismatch repair deficiency, TP53 mutations, or PTEN mutations): these represented 0.7% of all cases (2/300). The reclassified cases were originally diagnosed as grade 1 and 2 endometrioid carcinoma, and the latter had pulmonary metastases and pelvic recurrences. Six TTF-1 + cases retained their original serous (3) and endometrioid (3) diagnoses; 1 was reclassified as dedifferentiated. All had negative or low ER. KRAS mutations were identified in 4 TTF-1 + non–mesonephric-like cases, including 1 serous and 1 grade 3 endometrioid with p53 abnormalities, 1 mismatch repair–deficient endometrioid with a complex molecular profile, and 1 endometrioid with mucinous differentiation. These findings suggest that TTF-1 and ER are good first-line screens for mesonephric-like carcinoma, but caution that a TTF-1 + /ER − immunoprofile is not specific, even in the setting of KRAS mutations. A final diagnosis of mesonephric-like carcinoma requires integration of morphologic and immunohistochemical features, with molecular support when relevant.