h-Caldesmon, a Novel Smooth Muscle-Specific Antibody, Distinguishes Between Cellular Leiomyoma and Endometrial Stromal Sarcoma

Abstract

The difficulty in distinguishing between smooth muscle and endometrial stromal-derived neoplasms of the uterine corpus is a notorious and clinically relevant problem in pathology of the female genital tract. Immunohistochemistry offers some aid in resolving this difficulty, because the expression of smooth muscle markers is reputed to indicate smooth muscle derivation. This expression, however, is not entirely specific, and difficult cases may still present in which immunohistochemistry is of little help. To explore this problem, the authors evaluated the expression of traditional muscle markers and high-molecular-weight caldesmon (h-cal), an actin and tropomyosin binding protein that has recently been described as a useful muscle marker, in uterine leiomyosarcoma (LMS), cellular leiomyomata (CL), and endometrial stromal sarcoma (ESS). Formalin-fixed and paraffin-embedded tissue sections from nine LMSs, 11 CLs, and 12 ESSs were evaluated with commercially available monoclonal antibodies against smooth muscle actin (SMA), desmin, and h-cal. Established morphologic criteria were used to classify the neoplasms. We found that there was, as expected, a significant difference in the expression of traditional smooth muscle markers (SMA and desmin) between tumors derived from smooth muscle and those derived from endometrial stroma (p = 0.005 for LMS and 0.013 for CL). We further found that h-cal was most useful in distinguishing between CL and ESS (p = 0.01). A significant difference between h-cal expression in LMS versus ESS was not found. Of note, one ESS expressed both SMA and desmin but lacked h-cal expression. Our findings confirm the most useful immunohistochemical data to date; smooth muscle neoplasms are generally distinguishable from endometrial stromal tumors by the expression of conventional muscle markers. We also report here that h-cal is useful more specifically in the differentiation of CL from ESS.

JAZF1 and JJAZ1 gene fusion in primary extrauterine endometrial stromal sarcoma

“…Five of 6 cases were positive for CD10, representing a percentage of immunoreactive cases similar to that reported in the literature [4,[6][7][8][9][10]. Focal staining for desmin was present in 4 cases, similar to what has been previously described by several groups [32,33]. All cases were negative for h-caldesmon, which has been reported to have utility for differentiating ESS from other entities such as cellular leiomyoma [33].…”

Expression of CD10 in Malignant Müllerian Mixed Tumors and Adenosarcomas: An Immunohistochemical Study

“…However, occasional smooth muscle differentiation in ESS as represented by expression of ␣-SMA and/or desmin (24 -26) may lead to an erroneous interpretation of the results of immunohistochemistry. h-Caldesmon is considered to be a specific smooth muscle marker that is positive in welldifferentiated smooth muscle cells and negative even in desmin-and/or ␣-SMA-positive ESS and thus is considered to be useful in distinguishing smooth muscle tumor from ESS (27,28). Therefore, currently a panel employing a combination of CD10 and h-caldesmon seems contributory in making the distinction between ESS and smooth muscle tumor.…”

SIRT2 Expression Is Higher in Uveal Melanoma than In Ocular Melanocytes

“…Immunohistochemical SIRT2 expression was evaluated independently by two researchers assigning a score to each case according to their relative staining intensity, as previously described [25,26]. Briefly, intensity was scored as 0 (negative), 1 (weak), 2 (moderate) or 3 (strong).…”