[1037] Endometrial Adenosarcomas: Diagnostic Use of Ki-67 Proliferation Marker as an Adjunct to Morphologic Diagnosis

N Aggarwal, R Bhargava, E Elishaev. University of Pittsburgh School of Medicine, Pittsburgh, PA

Background: Endometrial adenosarcomas (AS) are rare biphasic neoplasms of the female genital tract containing benign glands and a low grade sarcomatous mesenchymal component. Diagnostic criteria include increased stromal cellularity in periglandular distribution (periglandular stromal cuffing) accompanied by variable degrees of cytologic atypia and mitotic activity. When not all the criteria are fulfilled a diagnosis of benign lesions are given and AS is considered in retrospect upon recurrence of the tumor.
Design: Eight cases of AS were identified at Magee-Womens Hospital between 2004 and 2008 and were compared to 15 cases of endometrial polyps (EP) and 14 cases of atypical polypoid adenomyomas (APA). Pertinent 1-3 blocks/case were selected and stained for Ki-67 proliferation marker, caldesmon, smooth muscle actin (SMA), desmin, and CD10 with appropriate negative and positive controls.
Results: All cases of AS had a polypoid growth pattern with round or slit-like glands with or without papillary projections into gland lumen. Increased periglandular stromal cellularity was observed focally or diffusely in all cases (8/8) of adenosarcoma, which also demonstrated variable degrees of stromal nuclear atypia. The mitotic activity ranged from 1/10 high power fields (HPF) to 15/10HPF. All cases of AS demonstrated distinct increase in Ki-67 positive nuclei in the peri-glandular zone compared to adjacent stroma, regardless of the mitotic count. The average Ki-67 labeling index in peri-glandular zones of AS was 20 % compared to less than 5 % in adjacent stroma. This zonation was not observed in any case of APA or EP all of which showed scattered positive cells with less than 5% Ki 67 proliferation index. The AS stroma was positive for CD10, with variable focal positive staining for SMA and desmin, and was negative for caldesmon. APA showed positivity for all muscle markers with SMA being the most consistent and diffuse. EPs were negative for caldesmon, variably positive for desmin and SMA and diffusely positive for CD10.
Conclusions: Distinct increase in peri-glandular Ki-67 staining pattern is very helpful and Ki 67 should be considered as an adjunct to the routine morphologic diagnosis of AS. This could be especially useful in curettage specimens and other challenging lesions that lack some of the classic criteria of an AS.
Category: Gynecologic & Obstetrics

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 145, Monday Morning

 

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