Purpose: The purpose of this study was to evaluate the radiologic features 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 leiomyomas and 10 leiomyosarcomas). Available radiologic studies indicated abnormal CT scans in 11 patients, double contrast barium studies in 4, and pelvic MRI in 1. On imaging, we evaluated the size, tumor margin, (smooth or lobulated), morphologic appearance, growth patterns, (endocolic, exocolic, or combined), contrast enhancement patterns, presence or absence of calcification within the tumors, and metastasis.
Results: The involved tumor sites were the colon in 2 patients and the rectum in 10. The mean tumor sites were the colon in 2 patients and the rectum 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 margin was smooth in three patients and lobulated in nine, with endocolic growth in one, exocolic in four, and combined in the remaining seven. Eight of the 12 tumors showed verying degrees of internal necrosis with heterogenous 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 suggested especially when the tumor occuring in the colorectum shows exocolic growth or calcification with varying degree of internal necrosis.
