Presentation
Abdominal pain and distension associated with anorexia and nausea for 1 week. Constipation for 3 days. 8 kg weight loss in last 3 months.
Patient Data
Distended colon up to the level of the splenic flexure with multiple air fluid levels. No signs of small bowel obstruction. No pneumoperitoneum.
Eccentric mural thickening of the distal descending colon causing almost complete luminal occlusion, leading to mild to moderate dilatation of the proximal colon which is filled with fluid and fecal matter. An ill-defined, irregular extra-luminal soft tissue mass containing multiple small calcifications is noted adjacent to this abnormal colonic segment just anterior to the L5/S1 intervertebral disc. Multiple prominent sub centimeter loco-regional lymph nodes are seen around this affected colonic segment. A nodule, likely a lymph node, measuring 11 x 14 mm is seen in the left iliac fossa. Two lymph nodes measuring 12 x 15 mm (pre-sacral location) and 13 x 22 mm (left pelvic side wall) are also noted.
Status post cholecystectomy and left nephrectomy. A few simple right renal cortical cysts. Small hiatal hernia and small fat containing umbilical hernia.
An irregular soft tissue mass measuring about 26 x 35 mm, containing calcifications, is seen anterior to L5 and S1 vertebral body, which is likely originating from the mesenteric fat and has associated desmoplastic reaction. Mild asymmetrical mural thickening of the distal descending colon without any proximal colonic obstruction, is noted adjacent to the aforementioned soft tissue abnormality.
An irregular hypoechoic heterogeneous lesion measuring 26 x 33 mm, containing calcifications, likely arising from the 4th layer (muscularis propria) of the descending colon is noted.
- Irregular partially calcified extra-colonic soft tissue mass with associated desmoplastic reaction, showing no gross interval change on the follow-up scan. Possible differentials include sclerosing mesenteritis and carcinoid tumor.
- Interval increase of eccentric/asymmetrical mural thickening of the distal descending colon associated with near complete luminal occlusion leading to proximal colonic dilatation, on the follow-up scan, suspicious of a colonic malignancy.
- Colonoscopy (after 2nd CT scan): No mucosal ulceration or tumor is seen. Luminal narrowing with mucosal edema noted in the descending colon, which is likely secondary to the extramural or submucosal mass lesion.
- Colonoscopic biopsy showed benign colonic mucosa with superficial hyperplastic changes. No dysplasia or malignancy seen.
- EUS guided FNAC: Non-diagnostic (predominant blood with only rare epithelial cells).
- Later on the patient underwent laparotomy with sigmoid colon resection.
Case Discussion
Histopathology of resected sigmoid colon: Sclerosing mesenteritis. IgG4/IgG ratio is around 20%. 15 reactive lymph nodes. No colonic malignancy is seen.
Microscopy: Sections from the tumor area show spindle cell proliferation extending from the muscularis propria to serosa. There are moderate lymphocytic and plasma cell infiltration within the tumor area. No atypia or necrosis is seen.
A panel of immunostains (including panCK, SMA, desmin, S100, CD117, DOG-1 and Ki-67) was performed which were negative in the spindle cells confirming the benign nature.
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