A rare case of low-grade endometrial stromal sarcoma with myxoid differentiation and atypical bizarre cells

Endometrial stromal sarcoma (ESS) is a rare mesenchymal tumor with characteristic histological appearances, consisting of diffuse infiltrate of small uniform endometrial stromal cells with a multinodular arrangement and distinct vascular pattern. Less common variants of ESS include "mixed endometrial stromal and smooth muscle tumors", "endometrial stromal tumors resembling ovarian sex cord tumors" and "endometrial stromal neoplasms with endometrial glands", and "aggressive endometriosis". Rarely do endometrial stromal tumors have a prominent fibrous or myxoid appearance which causes confusion and possible misdiagnosis as myxoid leiomyosarcoma. In this report we present a very unusual subtype of ESS in a 32-year-old woman. The tumor revealed atypical pleomorphic bizarre cells which were stained positive only with vimentin and CD10 in an abundant myxoid matrix. A low-proliferative rate was established with MIB- I staining. To our knowledge such appearance has not been previously reported.

Uterus, Endometrial Stromal Sarcoma, Myxoid change, Bizarre cells

[1] Bodner K., Bodner-Adler B., Obermair A. et al.: “Prognostic parameters in endometrial stromal sarcoma: A clinicopathologic study in 31 patients”. Gynecol. Oncol., 2001, 81, 160.

[2] Al-Nafussi A.: “Female genital tracts”. In: Al-Nafussi A. (ed.) “Tumor Diagnosis, Practical Approach and Pattern Analysis”. New York, Oxford University Press Inc., 2005, 365.

[3] Oliva E., Clement PB., Young R.H. et al.: “Mixed endometrial stromal and smooth muscle tumors of the uterus: a clinicopathologic study of 15 cases”. Am. J. Surg. Pathol., 1998, 22, 997.

[4] Ohta Y., Suzuki T., Kojima M. et al.: “Low grade endometrial stromal sarcoma with an extensive epithelial-like element”. Pathol. Int., 2003, 53, 246.

[5] Pang L.C.: “Endometrial stromal sarcoma with sex cord-like differentiation associated with tamoxifen therapy”. South. Med. J., 1998, 91, 592.

[6] Kasashima S., Kobayashi M., Yamada M. et al.: “Myxoid endometrial stromal sarcoma of uterus”. Pathol. Int., 2003, 53, 637.

[7] Yilmaz A., Rush D.S., Soslow R.A.: “Endometrial stromal sarcomas with unusual histologic features. A report of 24 primary and metastatic tumors emphasizing fibroblastic and smooth muscle differentiation”. Am. J. Surg. Pathol., 2002, 26, 1142.

[8] Oliva E., Young R.H., Clement P.B. et al.: “Myxoid and fibrous endometrial stromal tumors of the uterus: a report of 10 cases”. Int. J. Gynecol. Pathol., 1999, 18, 310.

[9] Fadare O., McCalip B., Mariappan M.R. et al.: “An endometrial stromal tumor with osteoclast-like giant cells: Expanding the morphological spectrum”. Ann. Diagn. Pathol., 2005, 9, 160.

[10] Zaloudek C., Hendricksen MR.: “Mesenchymal tumors of the uterus”. In: Kurman R.J, ed. “Blaustein’s Pathology of the female genital tract”. New York, Springer-Verlag, 2002, 561.