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One cause of umbilical lesions is a Meckel's diverticulum, which is subject to the ills that affect small bowel.
A woman of 70 was referred to the gastroenterology department with abdominal distension and umbilical discomfort. For many years she had been experiencing episodes of abdominal pain and distension which had passed off after a day or two. On examination she was found to have a firm 4 cm mass at the umbilicus and was referred urgently for a surgical opinion. Immediately after the clinic, however, she left for a foreign holiday. While abroad she developed an umbilical discharge and was seen by a local surgeon, who diagnosed omphalitis with a mass and raised the possibility of a Sister Joseph's nodule. An ultrasound scan revealed ‘an oval, well defined hypoechogenic lesion in the abdominal wall, possibly haematoma’. She returned to the UK and was admitted. Further ultrasound scanning showed a 6 cm soft-tissue mass abutting the small bowel and extending to the umbilicus. CT scanning confirmed this and a tumour of a urachal remnant was thought the most likely cause. Ultrasound-guided core biopsy showed poorly differentiated adenocarcinoma. No metastatic disease was seen on a chest radiograph or a CT scan of the liver.
At laparotomy the tumour was found to originate in a Meckel's diverticulum (Figure 1). The diverticulum was attached to the umbilicus, and a tumour arising from within was invading the anterior abdominal wall and was attached to the transverse mesocolon (Figure 2). The mass was resected en-bloc with the small bowel, the transverse mesocolon and a portion of abdominal wall. The abdominal wall was repaired with mesh. She recovered without incident. The lesion was a poorly differentiated adenocarcinoma arising in a Meckel's diverticulum adherent to the umbilicus. There was a track lined by granulation tissue to the umbilicus. The resection margins were clear, but two of eleven lymph nodes contained metastatic tumour (T4, N1, M0). After discussion at the gastrointestinal multidisciplinary team meeting the patient was seen by an oncologist and despite the probable limited benefit of chemotherapy she elected to proceed with treatment with 5-fluorouracil and folinic acid. Five months after her operation she returned with a palpable groin lymph node, which on biopsy showed metastatic adenocarcinoma with the same characteristics as the Meckel's carcinoma.
Meckel's diverticulum is a small portion of the vitelline duct that persists into adulthood as an outpocketing of the terminal ileum. The duct is formed in the first weeks of fetal life, representing the yolk stalk. It communicates with the yolk sac, passing through the umbilicus. Failure of the duct to be broken down and absorbed leads to congenital anomalies. Commonest is the Meckel's diverticulum which lies free within the abdomen, occurring in around 2% of the population. If part of the duct persists it can remain attached to the umbilicus as in this case, either patent or as a cord. In the case presented here the Meckel's diverticulum was connected to the umbilicus at its tip. It is possible that the episodes of pain over previous years were due to twisting of small bowel around this attachment, although small-bowel obstruction secondary to a Meckel's diverticulum with a fibrous cord is rare.
There are numerous recorded tumours of Meckel's diverticula. Tumours may be benign (such as villous adenoma1 and carcinoids2) but are more commonly malignant, led by adenocarcinoma3 and malignant carcinoid4. Rarer tumour types include fibrosarcoma5, leiomyosarcoma4 and melanoma6. Sister Joseph's nodule is so called because it was first described (to Dr William Mayo) by Sister Mary Joseph as an indicator of metastasis from an intra-peritoneal malignancy.
Adenocarcinomas of Meckel's diverticula are biologically similar to small-bowel adenocarcinomas, which tend to respond poorly to adjuvant therapy. Because they do not usually cause small bowel obstruction until locally advanced, they seem to have an even worse prognosis7.