Intestinal adenocarcinoma as unexpected content of Spigelian hernia: when CT-scan its not enough

Spigelian hernias are only 1-2% of all types and are considered a very uncommon condition: it develops through a weaker area between the semilunar line and the lateral edge of rectal muscle. There is an association with female sex, obesity, prior surgery, chronic obstructive pulmonary disease, abdominal trauma or coexistence of other wall defects. The content is intraperitoneal fat or omentum, sometimes small bowel or colon. Symptoms, like abdominal pain, lateral lump and altered bowel habits are linked to the most common complication: incarceration. The CT scan can be useful in confirming the abdominal wall defect and in discriminating the content and can help in the choice of the best surgical procedure, especially if there is an ischemia. In literature are described some case of atypical content, such as testicle in association with cryptorchidism in children or appendicular abscesses or abdominal wall tumor, especially in adults. We report a very unusual finding in a 81year-old patient: a well-differentiated intestinal adenocarcinoma of left colon as content of a left Spigelian hernia. The patient was admitted to our Department because of abdominal pain, left abdominal lump and altered bowel habits. The preoperative CT-scan showed a large defect in lateral left abdominal wall and a content of sigmoid colon with abscesses and diverticula, but there were not signs of ischemia. It was chosen an anterior direct approach, performed an adhesiolysis, isolated the left colon and identified the abdominal wall defect. Despite the absence of CT or clinical signs of ischemia, the colon was included in necrotic tissue and partially twisted. It was performed a left hemicolectomy through the hernia defect and side-toside colonic anastomosis reconstruction. After the bowel replacement, the abdomen wall was reconstructed without mesh or other devices in order to reduce the infection risk. The diagnosis of well differentiated (G1) intestinal adenocarcinoma, necrotic, infiltrating the bowel up the subserosa was performed only after histological examination. The CTscan was not able to differentiate the neoplasm from diverticular abscess, and even during the operation there was no a definite suspect, probably because the loss of normal anatomy due to the chronic inflammatory process. According to some studies the CT-scan has an importance in distinguishing the type of Spigelian hernia, but it is not so clear in discriminating the content, as it happened in our case, when the correct diagnosis of colon cancer concomitant with diverticula and abscess was possible only with the later microscopic examination.