Rare Metastasis of Colon Carcinoma Mimicking Endometrial Cancer

Introduction

Sigmoid colon cancer originates from the last part of the colon. The majority of these carcinomas (96%) are adenocarcinomas arising from glandular tissues. Metastases to the female genital tract from other malignancies are rare, with the most common extragenital origins being the breasts and the gastrointestinal (GI) system.^1,2 The ovary and the vagina are the most common metastatic sites for both extragenital and genital primaries. ¹

The aim of the present case report is to demonstrate a rare recurrence of colon cancer presenting with symptoms of the primary endometrial cancer.

Case

A 40-year-old woman was referred to the current authors' tertiary-care center for vaginal bleeding. She had been operated 4 years prior for cancer of the sigmoid colon. She had been incidentally diagnosed as having a mass in her sigmoid area when the mass was noted during a tubal ligation procedure. After she had been evaluated and operated on to remove her sigmoid-colon cancer, she was diagnosed with colon adenocarcinoma based on pathologic examination of the colon resection. A total of 12 cure chemotherapies, including oxaliplatin and fluorouracil (5-FU), were administered. All subsequent colonoscopies and investigations were uneventful during follow-ups, after she recovered from the procedures and chemotherapies.

However, subsequently, she was referred to the current authors' center with continuous vaginal bleeding complaints that had lasted for 1 month. Her rectovaginal examination was unremarkable. The laboratory results, including tumor markers, were normal (Ca125: 6.9 U/mL; Ca19-9: 1.2 U/mL; Ca15-3: 14.7 U/mL; α-fetoprotein: 2.2 IU/mL; and carcinoembryonic antigen: 2.8 ng/mL). Transvaginal sonographic evaluation revealed that her endometrium was hyperechogenic and the widest anteroposterior diameter in the midsagittal plane was 31 mm. There were no abnormalities in either of her ovaries. An endometrial biopsy was performed with a karman cannula. The pathology revealed metastasis of her sigmoid-colon adenocarcinoma with immunohistochemical results of vimentin (+), cytokeratin (+), cerb b2 (–), estrogen (–), and progesterone (–). All screening tests, including thoracic CT, abdominal CT, and a colonoscopy showed normal results in her whole body. PET/CT revealed that hypermetabolic activity involvement was only in the endometrial cavity with a maxium standardized uptake value (SUV_max) of 13.0. Total abdominal hysterectomy plus bilateral salpingo-oopherectomy was performed. Pathologic examination of the uterus revealed growth of a tumor lesion that was infiltrative, soft, and 5.5×5.5 cm in area, from her fundus towards her endometrial cavity. The myometrium was invaded by the tumor as far as 0.5 mm from the serosa (Fig. 1). The section of the endometrium showing showed metastatic colorectal carcinoma (H & E×40; Fig. 2).

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FIG. 1.

(A) Infiltrative, soft, tumor lesion, 5.5×5.5 cm, from fundus toward the endometrial cavity. (B) Myometrium invaded by the tumor as far as 0.5 mm from the serosa.

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FIG. 2.

Section of endometrium showing showed metastatic colorectal carcinoma (H&E×40).

Results

Postoperative PET/CT showed no evidence of any malignancies.

Discussion

Metastatic gynecologic cancers from extragenital cancers are relatively rare, and most of them originate from the GI system (especially colorectal cancers [37%]) and breast (34%). ¹ Metastases occur via the hematologic route or by lymphatic spreading. Colorectal cancer is the third most common malignancy for both genders worldwide. ³ The most common sites of distant metastases are the liver, regional lymph nodes, lungs, and peritoneum. ⁴ Isolated splenic, testicular (in men), vaginal cuff, and urethral metastasis have been reported in the literature.^5–8 To the best of the current authors' knowledge, there are only two reports published in 1982 and 1984 covering metastasis to the endometrium. Isolated endometrial metastases of the sigmoid colon cancer are quite rare.

Recurrent colorectal carcinoma usually develops within the first 5 years after resection. However, Pabuccu et al. published a case report titled “Late Recurrence of Sigmoid Carcinoma Mimicking Primary Vulvar Cancer: Case Report and Review of the Literature,” suggesting that recurrence time was 2 years after primary surgery. ⁹ Thus, a recurrence time of the tumor after >5 years would be considered to be a late recurrence.

Conclusions

Finally, an unusual metastasis should be considered in a woman who presents with abnormal vaginal bleeding, if she has a history of colorectal carcinoma.