Rectal ameboma: A new entity in the differential diagnosis of rectal cancer

Figure 1 Contrast-enhanced pelvic computed tomography images of a 46-year-old female patient. A: Lesion suggestive of malignancy on the rectal wall, ameboma (orange asterisk), increased density in the pararectal mesenteric tissue (green arrow); B: Only one of the lymph nodes in the pararectal region increased in number (yellow arrow); C: Sagittal image shows increased thickness of the rectal wall and calcified myoma (blue star) in the uterus; D and E: It is the magnified image of coronal plane image (D). This magnified image shows increased thickness of the rectal wall (orange asterisk) and lymph nodes in the coronal section (yellow arrow).

Figure 2 Contrast-enhanced pelvic magnetic resonance images of a 46-year-old female patient. A: Increased wall thickness in sagittal sections on T2-weighted magnetic resonance imaging, almost causing obstruction of the rectal wall (orange circle); B: Heterogeneity in mesocolic adipose tissue (white arrow) and asymmetric significant wall thickening in the rectum (orange asterisk) on T2-weighted axial magnetic resonance imaging; C: Lymph nodes in the perirectal region on diffusion weighted imaging (yellow arrow); D: T1-weighted axial post-contrast magnetic resonance images showing homogeneous contrast enhancement in the rectum with increased wall thickness (orange asterisk) and heterogeneity in mesorectal adipose tissue (white arrow).

Figure 3 Contrast-enhanced pelvic computed tomography images of a 46-year-old female patient after treatment. A: On the axial plane image, the thickness of the rectal wall appears to regress (orange asterisk); B: In the sagittal plane image, calcified myomas in the uterus (blue star) are seen in addition to regression of rectal wall thickening; C: Shrinkage of lymph nodes after treatment (yellow arrow).

Figure 4 The flowchart summarises our diagnostic and treatment process. CT: Computed tomography; MRI: Magnetic resonance imaging.