Low-grade stromal sarcoma: DNA flow cytometric analysis and estrogen progesterone receptor data.

DNA flow cytometry (FCM) data and estrogen receptor (ER) and progesterone receptor (PR) status were studied in three cases of low-grade stromal sarcoma (LGSS). One case was a primary presentation and the remaining two were recurrent tumors. DNA FCM showed a DNA index (DI) equal to 1.00, consistent with a diploid cell population, for four of the six specimens studied. The other two showed near-diploid populations. Proliferation indices (PI) were low in two of the patients' tumors (8.0 and 12.7%). These findings are consistent with the clinical history of LGSS and its propensity for indolent growth, long intervals between recurrences, and generally favorable prognosis. In case 2, a patient with several recurrences, the PI was increased to 20.3% in a specimen from the first recurrence. She subsequently recurred within 1 year with a more aggressive tumor, characterized by a mitotic index of greater than 10 mitoses/10 high-power fields (HPF), absence of ER and PR, and an aneuploid population (DI = 1.19). Receptor data, obtained by dextran-coated charcoal assay, showed that all tumors except the aggressive recurrence in case 2 had high ER (average 316 fmole/mg protein) and high PR (average 753 fmole/mg protein) levels. These ER and PR data are similar to the two other reports in the literature and the usual clinical response to progestational therapy was demonstrated. Further studies will help define the possible role of FCM and ER and PR determinations in patients with LGSS. These preliminary data suggest that they may be of prognostic significance.