ADENOMYOSIS WITH SPARSE GLANDS - A POTENTIAL MIMIC OF LOW-GRADE ENDOMETRIAL STROMAL SARCOMA

Most cases of adenomyosis are easily recognized by the presence of int ramyometrial aggregates of endometrial glands and endometrial stromal cells surrounded by hypertrophic smooth muscle. The authors report sev en cases of adenomyosis with sparse glands, which was a finding that i nitially caused difficulties in diagnosis and raised the question of l ow-grade endometrial stromal sarcoma (LGESS). The patients' ages range d from 51 to 81 years. All were postmenopausal. Each had undergone hys terectomy for a variety of reasons unrelated to the adenomyosis. Micro scopic examination of the uteri disclosed multiple intramural nests of adenomyotic endometrial stromal cells without endometrial glands, ran ging from 0.5 mm to 8.0 mm in maximum dimension. The percentage of ade nomyotic foci without glands in each case ranged from 40% to 94%. Two cases also had foci of intravascular intrusion by the gland-poor adeno myotic stroma. The most useful features for differentiating adenomyosi s with sparse glands from LGESS include: (1) its occurrence as an inci dental finding in uteri removed for other reasons; (2) the microscopic size of the adenomyotic foci without grossly evident tumor nodules; ( 3) a distinctive concentric zonal organization of the gland-poor strom al aggregates, with less cellular pale centers surrounded by a thin ri m of stromal or smooth muscle cells with increased cellularity, often with a thicker, but less well-defined, peripheral zone of hypertrophic myometrial smooth muscle; (4) the atrophic appearance of the stromal cells and absence of nuclear atypia and mitotic figures; (5) an absenc e of sclerotic areas, foam cells, sex cordlike structures, hemangioper icytoma-like vascular pattern, prominent vascular invasion and extraut erine extension commonly found in LGESS; (6) the presence of typical a denomyosis with glands elsewhere in the myometrium; and (7) the postme nopausal age of the patient.