An immunohistochemical comparison of ovarian and uterine endometrioid carcinoma, endometrioid carcinoma with clear cell change and clear cell carcinoma

Abstract

BACKGROUND: Endometrioid and clear cell carcinomas(CCC) of the gynecological tract show distinct clinicopathological profi les. Occasionally, endometrioid carcinomas(EC) exhibit clear cell change, mimicking CCC. This study compares the immunoprofi les of ovarian and uterine EC, EC with clear cell change(EC-CC) and CCC. DESIGN: Representative sections were selected from 62 CCC(38 ovarian, 24 uterine), 33 FIGO grade 1-2 EC(22 ovarian, 11 uterine) and 33 EC-CC(5 ovarian, 28 uterine) and stained for HNF1β, BAF250a(ARID1a), NapsinA, ER and PR. EC-CC slides showed≥10% CC areas, comprising either of squamoid, secretory or non-specifi c(NOS) change. Intensity of staining was scored as 0 to 3+ and extent of staining was scored as: 1+=<1%; 2+=≥1%to<10%; 3+=≥10%to<50% and 4+=≥50%. Any nuclear or cytoplasmic staining was considered positive for (HNF1β, ER and PR) and NapsinA respectively. Loss of BAF250a was defi ned as lack of nuclear staining in >90% of cells. RESULTS: 55/62(88.7%)CCC, 14/33(42.4%)EC-CC and 17/33(51.5%)EC showed immunoreactivity for HNF1 β and staining was≥2+ in≥10% of cells in 49/55, 10/14 and 9/17 cases, respectively. 54/62(87.1%)CCC, 4/33(12.1%)EC-CC and 2/33(6.1%) EC stained for NapsinA. 49/54CCC and 2/4uterine-EC-CC (both with NOS CC) demonstrated≥2+ staining in≥10% of cells. Staining was 3+ in <1% of cells in 2 EC(ovarian). 11/62(17.7%)CCC, 4/33(12.1%)EC-CC and 2/33(6.1%)EC showed loss of BAF250a. Four EC-CC(uterine) showed decreased expression of BAF250a in CC areas (2 secretory and 2 NOS changes). ER was expressed in 10/62(16.1%)CCC, 29/33(87.9%)EC-CC and 31/33(93.9%)EC, while PR was positive in 9/62(14.5%) CCC, 25/33(75.8%)EC-CC and 32/33(97.0%)EC. Decreased ER and PR expression was identifi ed in CC areas of 13/24(54.2%) and 6/21 (28.6%) uterine EC-CC as well as 4/5(80%) and 2/4(50%) ovarian EC-CC. Differences in immunoexpression of HNF1β, NapsinA, ER and PR in CCC versus EC-CC/EC were statistically signifi cant(p<0.0001). EC-CC showed a statistically signifi cant reduced PR positivity when compared to EC(p=0.0268). Although EC-CC also demonstrated a trend towards loss of BAF250a and ER, the difference in expression between EC-CC versus EC was not statistically signifi cant(p=0.67). CONCLUSIONS: EC-CC and EC show similar immunoprofi les. Use of HNF1β, NapsinA, ER and PR can help distinguish EC-CC from CCC.