Case Report
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World J Obstet Gynecol. Feb 10, 2014; 3(1): 21-25
Published online Feb 10, 2014. doi: 10.5317/wjog.v3.i1.21
Metastasis to a uterine leiomyoma originating from lung cancer: A case report
Shakina Rauff, Joseph S Ng, Arunachalam Ilancheran
Shakina Rauff, Department of Obstetrics and Gynaecology, National University Hospital, Singapore 119074, Singapore
Joseph S Ng, Arunachalam Ilancheran, Division of Gynaecologic Oncology, Department of Obstetrics and Gynaecology, National University Hospital, Singapore 119074, Singapore
Author contributions: Rauff S wrote the main draft of the article and acquisition of figures; Ng JS and Ilancheran A were responsible for the editing and revision of the article and final approval of the version to be published; Rauff S and Ilancheran A performed the surgical operation; all authors were the attending doctors for the patient.
Correspondence to: Dr. Shakina Rauff, MBBS, MRCOG, MMed, FAMS, Associate Consultant, Department of Obstetrics and Gynaecology, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore.
Telephone: +65-1-97947026 Fax: +65-1-67724769
Received: September 29, 2013
Revised: October 24, 2013
Accepted: November 2, 2013
Published online: February 10, 2014

The uterus is an uncommon site of metastasis especially from a primary lung adenocarcinoma. More frequently, extragenital primary tumours, including lung cancer, metastasize to the ovaries. In the literature, lung cancer metastasizing to the uterus is rare and has been reported to involve the endometrium and uterine serosa. Here, we report an unusual case of a 58-year-old woman who had a history of lung adenocarcinoma with subsequent metastasis to a single uterine fibroid only. The patient was known to have a long history of asymptomatic fibroids. In 2008, she was diagnosed with lung adenocarcinoma which was treated with primary surgery and adjuvant chemotherapy. Four years later, a routine abdominal computerised tomography scan showed an enlargement of the fibroid and she underwent a hysterectomy and bilateral salpingo-oophorectomy. Pathology reported a lung adenocarcinoma metastatic to the uterine leiomyoma with a similar morphology to the original pulmonary malignancy and this was confirmed with immunohistochemical staining. She had no evidence of metastatic disease elsewhere. The final diagnosis was metastasis of a primary lung adenocarcinoma confined to a uterine leiomyoma. Our patient also fulfilled the criteria for a phenomenon called tumour-to-tumour metastasis in this case a primary malignancy having metastasized to a benign tumour. In conclusion, metastasis of a primary lung cancer to the female reproductive tract has been documented, but clinicians should also be aware that metastasis to benign gynaecological tumours such as fibroids can also occur, especially in the setting of tumour-to-tumour metastasis. In addition, the clinical history and use of immunohistochemistry are invaluable in reaching a diagnosis.

Keywords: Uterine metastasis, Lung cancer, Metastasis to leiomyoma, Tumour-to-tumour metastasis, Lung adenocarcinoma metastasis, Metastasis to female genital tract

Core tip: Our paper describes a rare occurrence of metastasis from a lung cancer to a uterine leiomyoma only without involvement of the endometrium, serosa or adnexae. This has not been reported in recent literature. We also describe the utility of immunohistochemistry in reaching a diagnosis which was essential in our patient who was asymptomatic-unlike those previously reported. The phenomenon of “tumour-to-tumour” metastasis, which not many gynaecologists have heard of, is also described in our report. The importance of knowing that the formation of metastasis to the female genital tract, although uncommon, is highlighted.