Radiological features of leiomyomatous tumors of the colon and rectum

Purpose: The purpose of this study was to evaluate the radiological feature s of 12 pathologically proven cases of colorectal leiomyomatous tumors. Method: A retrospective analysis of radiologic findings was performed in 12 patients with pathologically proven colorectal leiomyomatous tumors (2 lei omyomas and 10 leiomyosarcomas). Available radiologic studies included abdo minal CT scans in 11 patients, double contrast barium studies in 4, and pel vic MRI in 1. On imaging, we evaluated the size, tumor margin (smooth or lo bulated), morphologic appearance, growth patterns (endocolic, exocolic, or combined), contrast enhancement patterns, presence or absence of calcificat ion within the tumors, and metastasis. Results: The involved tumor sites were the colon in 2 patients and the rect um in 10, The mean tumor size was 7.9 cm (range 2-15 cm): It was 3.5 cm in leiomyomas and 8.8 cm in leiomyosarcomas. On imaging studies, the tumor mar gin was smooth in three patients and lobulated in nine, with endocolic grow th in one, exocolic in four, and combined in the remaining seven. Eight of the 12 tumors showed varying degrees of internal necrosis with heterogeneou s contrast enhancement. Dystrophic calcification was noted in five patients . Metastasis was seen in the liver in three patients at the time of initial diagnosis, and lymphadenopathy was noted in two patients (paraaortic space in one and perirectal space in two). Conclusion: Although rare, the diagnosis of leiomyomatous tumor may be sugg ested especially when the tumor occurring in the colorectum shows exocolic growth or calcification with varying degree of internal necrosis.