Locally advanced sigmoid cancer

Case contributed by Mohammad A. ElBeialy


Rectal bleeding and loss of weight.

Patient Data

Age: 80 years

There is a large distal sigmoid tumor with an additional 3 cm paracolic mass. There is a focal interruption of the intervening fat plane between the tumor and the posterior wall of the urinary bladder which appears irregularly thickened. Enlarged node adjacent to left external iliac vessels, and small node in right pelvic sidewall. No signs of intestinal obstruction or pneumoperitoneum. No hepatic deposits or upper abdominal adenopathy. Moderate prostatic enlargement.

Findings consistent with sigmoid cancer, staging T4 (bladder invasion) N1 M1 (external iliac node)

Due to some doubt as to bladder invasion, MRI was requested. Please note that MRI is not otherwise indicated for sigmoid colon cancer staging.

There is a distal sigmoid mass lesion about 5 x 4.5 cm noted about 13.5 cm from the puborectalis sling (dentate line) and about 18 cm above the anal verge. It extenda beyond the muscularis propria.  There is no line of cleavage between the sigmoid tumor and the posterior wall of the urinary bladder and hence if confirmed invasion, it could be staged as T4 b. There is enlarged large left mesorectal malignant mass lesion about 4 x 3.6 cm.  There are small right pelvic sidewall as well as left external iliac lymph nodes.

There is peri-colic linear infiltration, suggestive of extramural vascular invasion (EMVI).

The prostate appears enlarged with lobulated outline as well as heterogeneous parenchyma.

Heterogeneous appearance of the bones is noted with no otherwise overtly destructive bony lesions.

No pelvic collection.

In summary, the MRI confirms a T4 status with bladder invasion.

Histology Report:

Nature of Specimen: Proximal sigmoid biopsy

Clinical Details: Sigmoid tumor

Macroscopic Description: Pot labeled Proximal sigmoid bx - Multiple pieces of mucosa ranging in size from 1mm to 3mm in maximum dimension. All processed.

Microscopic Description: This specimen contains large intestinal mucosa showing ulceration and associated granulation tissue formation. There is high grade dysplasia and features that are highly suspicious for moderately differentiated adenocarcinoma with invasive malignancy.

PET-CT was requested to clarify the status of the pelvic sidewall lymph nodes, although it is noted that either a positive or negative status would lead to the same outcome of the patient being offered chemotherapy if medically fit.

Nuclear medicine

FDG avid uptake is identified within a lesion in the distal sigmoid colon. No tissue plane with the adjacent bladder is identified. An adjacent necrotic soft tissue nodal mass lesion is identified.

FDG avid pelvic lymph nodes are identified in both pelvic sidewalls and adjacent to the left external iliac vessels.

A focus of FDG avid uptake is seen within the left sacral ala. A focus of FDG avid uptake is noted within the left lobe of the prostate gland, this could be an incidental prostatic malignancy which will need correlation with a PSA level and urology opinion.

The patient received systemic chemotherapy, which is the standard therapy for this type of malignancy.

MRI 6 months later


The known distal sigmoid tumor has significantly increased in size now measuring 7.8 x 9.6cm and previously measured as 5 x 4.5cm. This mass now occupies most of the pelvis. Right margin of the tumor seen to invade into the right pelvic sidewall. This tumor is pushing the bladder forward and abutting the posterior wall of the bladder which appears thickened with no plane of cleavage seen. EMVI positive. Previously seen, 4cm left mesorectal mass lesion is no longer seen separate from the rectosigmoid tumor. Several small inguinal and pelvic sidewall lymph nodes seen bilaterally. No significant change except right inguinal lymph node which has slightly increased in size, now measuring 8mm and previously 4.4mm. Enlarged prostate with nodular appearance. There is no fat plane between the prostate and the rectosigmoid tumor. No free fluid or collection.

There is abnormal marrow signal seen in the left sacrum and this may correlate with avid FDG uptake seen in the PET CT.

This tumor would be radiologically staged as T4b N2 M1a.

Case Discussion

Imaging is consistent with a locally advanced sigmoid carcinoma and small volume pelvic nodal deposits.  There was disease progression despite systemic chemotherapy.

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