Sections of the sigmoid mass-like lesion demonstrate a florid transmural dense acute inflammatory process surrounding lumens of diverticula showing all layers of colonic wall. Centrally, there are focal areas of liquefactive necrosis and fibrinopurulent exudate, consistent with abscess formation. The surrounding stroma shows exuberant granulation tissue and organizing fibrosis, which extends into the subserosal adipose tissue. All fifteen (15) regional lymph nodes show reactive follicular hyperplasia. No evidence of specific granulomas. No evidence of atypia or malignancy.
Aggressive sigmoid colon mass like lesion causing a large bowel obstruction, with radiological signs suggestive of bowel wall ischemia (pneumatosis colitis), regional lymph node involvement, and mild ascites.
The specimen consists of a segment of sigmoid colon measuring 42 x 2.5 x 2 cm, with attached mesenteric fat measuring 25 x 3 x 2 cm. Serial sectioning of the bowel reveals a distinct area of obstruction measuring 9 x 3 cm. This obstructing lesion is located 2 cm from the nearest resection margin and 30 cm from the opposite resection margin. Gross examination and sectioning of the attached mesenteric fat yield a total of 15 lymph nodes, with the largest lymph node measuring 0.5 cm in maximum diameter.