Hamartomatous polyposis in tuberous sclerosis complex: Case report and review of the literature.

Tuberous sclerosis complex (TSC) is a genetic disorder with multisystem involvement that is due to autosomal-dominantly inherited or sporadic mutations in TSC1 and TSC2 genes. Involvement of the gastrointestinal tract is rare. We report the case of a 51-year-old woman with diagnosis of TSC established by genetic testing, who presented with colorectal hamartomatous polyposis. Multiple small polyps were found scattered through the left colon and rectum. Histology revealed a distinct spindle cell proliferation in the lamina propria, originating from the muscularis mucosae. The cells lacked atypia or mitotic activity and were diffusely positive for smooth muscle actin and negative for S100 protein. Genetic testing proved a disease causing frameshift mutation in the TSC1 gene. Although gastrointestinal involvement is rare in TSC, hamartomatous polyps can be the initial manifestation of this syndrome. Genetic testing should be considered in every case for which TSC is clinically suspected.