[1159] Atypical Uterine Polyps Sub-Diagnostic of Mullerian Adenosarcoma: A Clinicopathologic Analysis of 28 Cases with Long Term Followup

Brooke E Howitt, Bradley J Quade, Marisa R Nucci. Brigham and Women's Hospital, Boston, MA

Background: Mullerian adenosarcoma (MA) is a rare mixed tumor composed of benign glands with papillary (leaf-like) or dilated glands and frequent polypoid intraluminal projections of neoplastic stroma; however, the diagnosis is challenging because many lesions are subtle. We examined the clinicopathologic features and outcome of patients who had uterine polyps that raised the possibility of, but were not diagnostic for, MA.
Design: A search of institutional archives (1990-2011) for biopsies diagnosed as atypical endometrial or endocervical polyps that had some, but not all, features of MA was performed and 28 cases were retrieved. The frequency of the diagnosis of benign uterine polyp in this time frame was also determined. All 28 cases were evaluated for presence/absence and distribution (focal vs diffuse) of stromal cellularity, altered periglandular stroma, stromal atypia, mitoses, phyllodes-like architecture, intraluminal polypoid projections, and rigid cysts. Partial involvement of the polyp was also recorded. Clinical followup data was obtained when possible.
Results: The diagnosis of atypical endometrial polyp was made in < 0.2% of all uterine polyps diagnosed at our institution. 27/28 (96%) cases had followup (f/u) information; 15 (56%) had f/u biopsy(ies) only, 9 (32%) had TAH +/-BSO, and 3 (11%) had clinical f/u without further pathologic sampling. 1 patient died of pancreatic cancer, but all other patients are alive with NED (range in f/u 5.8-236 mo; mean 142.6 mo). 1 case was reclassified as MA on our review; this patient had benign f/u biopsy and is disease free at 82 mo. 23 (82%) cases showed partial involvement of the polyp. The most common findings were: periglandular stromal alteration (86%; 4 focal, 2 vague); phyllodes-like architecture (79%; 8 focal, 1 multifocal); and rigid cysts (46%). Intraluminal polypoid projections in the absence of phyllodes architecture were uncommon. Stromal atypia was rare (2 cases; 1 focal, 1 multifocal). Mitoses ranged from 0-11/10 HPF; and were not seen in 8 cases. The case with the highest mitotic count had partial involvement of the polyp, focal phyllodes-like architectural changes, and diffuse periglandular stromal alteration.
Conclusions: While periglandular stromal alterations and phyllodes-like architecture often prompt consideration of MA, uterine polyps that have some, but not all features of MA, have a benign clinical followup and need not be treated by hysterectomy if careful followup is feasible. Reconsideration of the threshold for diagnosis of MA also is warranted.
Category: Gynecologic & Obstetrics

Monday, March 19, 2012 11:00 AM

Platform Session: Section E, Monday Morning


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