Case Report

Malignant Mixed Mullerian Tumor of the Uterus Associated with Tamoxifen Therapy in a Patient with a History of Breast Cancer

Zahra Eftekhar, Fariba Yarandi, Narges Izadi-Mood, Parvaneh Rahimi-Moghaddam

Current Author Addresses: Zahra Eftekhar, Department of Gynecologic Oncology, Mirza-Koochak-Khan Hospital, Tehran University of Medical Sciences. Nejatollahi St. Karim Khan Zand Ave. Tehran, Iran. Phone: +98 (21) 6693 9320, Fax: +98 (21) 6693 7321 E-mail: par127@mail.usask.ca (Corresponding Author).
Fariba Yarandi, Department of Gynecologic Oncology, Iran University of Medical Sciences, Mirza-Koochak-Khan Hospital, Tehran University of Medical Sciences.
Narges Izadi-Mood, Department of Pathology, Mirza-Koochak-Khan Hospital, Tehran University of Medical Sciences.
Parvaneh Rahimi-Moghaddam, Razi Institute for Drug Research, Iran University of Medical Sciences, Tehran, Iran.

Received June 16, 2005; Revised May 29, 2006; Accepted June 3, 2006

Code Number: pt06014

ABSTRACT

Tamoxifen is the drug of choice in the treatment of breast cancer. Recent reports show an increased incidence of endometrial carcinoma in patients taking tamoxifen. In this article, we report a case of malignant mixed mullerian tumor after tamoxifen use.

Keywords: Tamoxifen, Breast cancer, Endometrial cancer, Case report

Tamoxifen therapy is known to increase the risk of endometrial carcinoma. Most of these malignancies are endometrial adenocarcinma, but occurrence of endometrial sarcoma has been reported as well [1-6]. Here, we report a woman who developed a malignant mixed mullerian tumor after use of tamoxifen for 5 years.

Case Report

A 72-year-old woman, gravida 6, para 6, live child 4, was admitted to our gynecologic clinic because of post-menopausal vaginal bleeding for two months. Her medical history showed a standard radical left mastectomy after the diagnosis of left breast cancer at age 60. She received an oral dose of 200mg tamoxifen daily for 5 years. In physical exam, she had a big uterus approximately in size of uterus of a 16-weeks pregnant woman. Abdominal ultrasound image showed a big uterine mass (3 × 2.9 × 1.8 cm) in endometrial area in association with liquid accumulation in adnexae. CT scan showed no bone involvement. An endometrial biopsy was obtained which showed a mixture of carcinomatous and sarcomatous elements. In sarcomatous component, pleomorphic cells with atypical mitoses and bizarre tumoral giant cells were observed (Fig 1). In the carcinomatous part, malignant epithelial cells were arranged in tubular structures or cords (Fig 2). The preliminary pathological diagnosis was malignant mixed mullerian tumor. We performed laparotomy with a pre-operative diagnosis of malignant uterine mass. A total abdominal hysterectomy and bilateral salpingo-ophorectomy and pelvic lymph node sampling were performed. In gross examination, there was a polypoid tumoral mass measuring 5 x 4 cm in diameter which occupied endometrial cavity. The tumor invaded full thickness of the myometrium. In microscopic examination, tumor consisted of tumoral epithelial cells with foci of pleomorphic atypical spindle cells. Omentum and liver were involved as well. The diagnosis of malignant mixed mullerian tumor was made.

Discussion

Tamoxifen, a partial agonist of estrogen, has been widely used in the treatment of breast cancer. In the recent yeas, the occurrence of uterine malignancy in patients receiving tamoxifen has been identified. These malignancies have been reported as adenocarcinoma as well as uterine sarcoma. In women not taking tamoxifen, fewer cases of uterine malignancies have been observed when compared with those taking the drug.

Tamoxifen is a complex drug with both agonist and antagonist effects on estrogen receptors. This mixture agonist and antagonist properties may explain both efficacy and toxicity of tamoxifen. Toxic effects of tamoxifen are observable throughout the entire urogenital tract including vaginal epithelium, cervix, uterine corpus, endometrium an ovaries. Tamoxifen has a proliferative effect on endometrial stromal cells and this effect is intensified by higher doses of drug as well as a longer time of its use [7-8].

Overall, benefits of tamoxifen in the treatment and prevention of breast cancer is much higher than its risk for uterine malignancies. It should be kept in mind that high-risk patient for endometrial cancer should be identified before tamoxifen therapy. Also, in patients receiv ing tamoxifen, regular uterine sonography in conjunction with endometrial biopsies would be appropriate for early diagnosis of endometrial malignancies.

References

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Copyright © 2005 by Razi Institute for Drug Research (RIDR)