Leiomyomatosis-like lymphangioleiomyomatosis of the colon in a female withtuberous sclerosis

Smooth muscle lesions of the large bowel, excluding the rectum, are general ly rare, and diffuse smooth muscle lesions, termed leiomyomatosis, are even rarer. In this report, we document, for the first time, leiomyomatosis-lik e lymphangioleiomyomatosis (LAM) of the ascending, transverse, and descendi ng colon in association with bilateral renal angiomyolipoma (AML) in a 30-y ear-old Chinese female with tuberous sclerosis complex (TSC). She presented with protracted constipation for which a colectomy was performed. Histolog y disclosed multiple confluent nodular CD34 and CD117 negative smooth muscl e proliferation within the large bowel wall, whereas the renal biopsy revea led typical features of AML. Interestingly, the epithelioid smooth muscle c ells of both the colonic and renal lesions were HMB45 positive, suggesting that leiomyomatosis-like LAM of the colon, pulmonary LAM and AML are closel y related entities. The patient remained free of complications for the last five years after surgery. Leiomyomatosis-like LAM of the large bowel proba bly represents another manifestation of the tendency of TSC to be associate d with proliferative lesions.