A rare case of primary leiomyosarcoma of the sigmoid colon & urothelial carcinoma of the bladder in a Crohn’s patient

Jessica S Crystal, MD1, Steven Tizio, MD2, Min Zheng, MD2, Glenn Parker2. 1Rutgers-Robert Wood Johnson Medical School, 2Jersey Shore University Medical Center

Primary leiomyosarcomas of the gastrointestinal (GI) tract are highly aggressive and rare neoplasms.   While a known association exists between leiomyosarcomas and immunosuppression, only a small cohort of cases have been noted to have been identified in the sigmoid colon, and found simultaneously with a urothelial carcinoma. To our knowledge, this is the first case of the simultaneous presentation of colon leiomyosarcoma and urothelial carcinoma of the bladder. Here, we report a case of a primary leiomyosarcoma of the sigmoid colon, in a patient with Crohn’s Disease and arthritis who is currently being treated with humira and lialda, who was simultaneously found to have an urothelial carcinoma.

The patient is a 57 year old female who presented for a screening colonoscopy, and was found to have a 3.5 cm friable mass, 40 cm proximal to the anal verge.  Initial pathology was consistent with a spindle cell tumor.  The patient then underwent, rectosigmoid colon resection with primary anastamosis, cystoscopy, and trans-uretheral resection of bladder tumor.  Final pathology showed a well, pedunculated, firm rectosigmoid colon mass with slightly friable/ulcerated surface. The mass was found to be high grade (up to 40-50 mitoses per 10 high power fields) and a high Ki67/MIB1 labeling index of 70%.  The tumor cells strongly express smooth muscle actin and were negative for c-KIT, DOG-1, pankeratin, CD34, and S100.  The bladder mass was a pale-pink, tan lesion found to be a high grade papillary non-invasive urothelial carcinoma with no invasion into the muscularis propria and no lymphovascular invasion.

In conclusion, sigmoid colon leiomyosarcoma is a rare neoplasm, but is a diagnosis that should be considered in the setting of immunosuppression.  Furthermore, this is the first report of the finding of this neoplasm in the colon in the setting of an urothelial carcinoma of the bladder.

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