From: Magnetic resonance imaging and endorectal ultrasound for diagnosis of rectal lesions
 | Anal carcinoma | Rectal carcinoma | Carcinoid of the rectum | GIST |
---|---|---|---|---|
T | Primary tumor | Â | Â | Â |
TX | Primary tumor cannot be assessed | Primary tumor cannot be assessed | Primary tumor cannot be assessed | Primary tumor cannot be assessed |
T0 | No evidence of primary tumor | No evidence of primary tumor | No evidence of primary tumor | No evidence of primary tumor |
Tis | Carcinoma in situ, Bowen disease, high-grade squamous interepithelial lesion (HSIL), anal interepithelial neoplasia II-III (AIN II-III) | Carcinoma in situ: intraepithelial or invasion of lamina propria | Â | Â |
T1 | Tumor 2Â cm or less in the greatest dimension | Tumor invades submucosa | Tumor invades lamina propria or submucosa and is no greater than 2Â cm in size | Tumor 2Â cm or less in greater dimension |
T1a – tumor less than 1 cm in size | ||||
T1b – tumor 1 to 2 cm in size | ||||
T2 | Tumor more than 2Â cm but not more than 5Â cm in the greatest dimension | Tumor invades muscularis propria | Tumor invades muscularis propria or is greater than 2Â cm in size | Tumor more than 2Â cm but not more than 5Â cm |
T3 | Tumor more than 5Â cm in the greatest dimension | Tumor invades subserosa or into non-peritonealized perirectal tissues | Tumor invades subserosa or non-peritonealized perirectal tissues | Tumor more than 5Â cm but not more than 10Â cm |
T4 | Tumor of any size invades adjacent organ(s), e.g., vagina, urethra, bladder (direct invasion of rectal wall, perianal skin, subcutaneous tissue or the sphincter muscle(s) alone is not classified as T4) | Tumor perforates visceral peritoneum (T4a) and/or directly invades other organs or structures (T4b) | Tumor perforates peritoneum or invades other organs | Tumor more than 10Â cm in the greatest dimension |
N | Regional lymph nodes | Â | Â | Â |
NX | Regional lymph nodes cannot be assessed | Regional lymph nodes cannot be assessed | Regional lymph nodes cannot be assessed | Regional lymph nodes cannot be assessed |
N0 | No regional lymph nodes metastasis | No regional lymph nodes metastasis | No regional lymph node metastasis | No regional lymph nodes metastasis |
N1 | Metastasis in perirectal lymph nodes | Metastasis in 1 to 3 regional lymph nodes | Regional lymph node metastasis | Regional lymph node metastasis |
N1a - Metastasis in 1 regional lymph node | ||||
N1b – Metastasis in 2 to 3 regional lymph nodes | ||||
N1c Tumor deposit(s), i.e. satellites, in the subserosa or in non-peritonalized pericolic or perirectal soft tissue without regional lymph node metastasis | ||||
N2 | Metastasis in unilateral internal iliac and/or inguinal lymph nodes | Metastasis in 4 or more regional lymph nodes | Â | Â |
N2a - metastasis in 4 to 6 more regional lymph nodes | ||||
N2a - metastasis in 7 or more regional lymph nodes | ||||
N3 | Metastasis in perirectal and inguinal lymph nodes and/or bilateral internal iliac and/or bilateral inguinal lymph nodes | Â | Â | Â |
M | Distal metastasis | Â | Â | Â |
M0 | No distal metastasis | No distal metastasis | No distal metastasis | No distal metastasis |
M1 | Distal metastasis | Distal metastasis | Distal metastasis | Distal metastasis |
M1a – metastasis confined to one organ | ||||
M1b – metastasis in more than one organ or the peritoneum |