Malignant Stromal Tumor Consistent with Fibrosarcoma Arising from Meckel's Diverticulum. Clinicopathological Study of an Incidentally Discovered Tumor and Review of the Literature

A Case of Carcinoid of Meckel's Diverticulum Associated with Gastric Adenocarcinoma

Meckel's diverticulum is an uncommon gastrointestinal congenital anomaly that occurs in 1-3% of the population. It is sometimes associated with complications related to the presence of ectopic tissue (obstruction, ulceration, hemmorhage, inflammation, perforation, fistula and tumors). Neoplastic degeneration of Meckel's diverticulum mucosa is rare, developing in only 1-5% of all diverticula, usually asymptomatic and occasionally discovered. Disease is metastatic, usually to the liver, in 25% of cases. We report a case of asymptomatic unsuspected carcinoid of Meckel's diverticulum with ileal, hepatic and mesenteric metastasis discovered during a gastrectomy performed for gastric adenocarcinoma. The patient underwent ileal and Meckel diverticulum resection, excision of mesenterial metastasis and liver bisegmentectomy. Furthermore, total gastrectomy with esophago-jejunal anastomosis was performed. After an 18-month follow-up period, the patient is alive and disease free. Owing to possible neoplastic degeneration, Meckel's diverticulum should be resected when occasionally discovered. In the presence of a carcinoid tumor, even if associated with metastatic disease, extended resection is recommended.

[A pseudotumoral lesion revealing Meckel's diverticulum]

INTRODUCTION

Meckel's diverticulum is a common malformation in children, usually asymptomatic, with complications in only 20% of cases. Exceptionally, a tumor can develop in Meckel's diverticulum in children, particularly Burkitt's lymphoma; in adults it can develop into a gastrointestinal stromal tumor, a leiomyosarcoma, or a neuroendocrine tumor such as a carcinoid tumor. The diagnosis of inflammatory pseudotumor following an insidious perforation is rare.

OBSERVATION

We report the case of a 14-month-old boy who presented with fever, asthenia, food refusal, and digestive complaints such as vomiting and tender abdomen suggesting appendicitis. Computed tomography showed an ileal mass of 3cm in diameter, which led to the suspicion of Burkitt's lymphoma. Laparoscopy showed Meckel's diverticulum with a mass of 3×2.8×2cm. Histological examination confirmed the diagnosis of Meckel's diverticulum with gastric heterotopia and showed a proliferation of spindle cells in a myxoid background, with an inflammatory infiltrate made of lymphocytes and plasmocytes. Immunostaining ruled out a malignant tumor. The diagnosis of an inflammatory pseudotumor developing on a Meckel diverticulum with gastric heterotopias was made. The outcome was favorable after surgical resection.

CONCLUSION

While perforation of a Meckel diverticulum with gastric heterotopia is a common finding, the discovery of an inflammatory pseudotumor following a perforation is rare; the differential diagnosis should include Burkitt's lymphoma.

[Retrospective diagnosis of stromal tumor with liver and nodal metastasis in a hemorrhagic Meckel's diverticulum appearing 8 years after the first resection]

Meckel's diverticulum is the most prevalent congenital abnormality of the gastrointestinal tract (0.3-4%). The gastrointestinal stromal tumours (GIST) are rare tumours. Only few cases of GIST developed in Meckel's diverticulum have been published in the literature. We reported a case of a woman with a diagnosis of GIST of Meckel's diverticulum retrospectively made 8 years after the resection of an haemorrhagic Meckel's diverticulum, whom she developed a large size intra-abdominal tumour with liver and nodes metastasis.

Gastrointestinal stromal tumours: a regular origin in the muscularis propria, but an extremely diverse gross presentation. A review of 200 cases to critically re-evaluate the concept of so-called extra-gastrointestinal stromal tumours

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are thought to arise from the interstitial cells of Cajal (ICCs). ICCs form a network surrounding the myenteric plexus and between-muscle fibres of the muscularis propria of the tubular GI tract. The cell of origin of so-called extra-gastrointestinal stromal tumours (EGISTs) is not known.

AIM AND METHODS

To study the diversity of gross presentation of GISTs and to critically assess the incidence of EGISTs and their relationship to mural GISTs, a total of 200 neoplasms with typical morphologic and immunohistochemical features of GISTs were reviewed, looking for any degree of association with the muscularis propria of the gut wall.

RESULTS

There were 130 gastric (65%), 9 duodenal (4.5%), 48 small intestinal (24%), 9 colorectal (4.5%), 1 appendiceal (0.5%) and 3 unclassifiable GISTs (1.5%). Fourteen cases (7%) were initially submitted as EGISTs (four mesenteric, four omental, one pararectal/prostatic, one pelvic/Douglas, one perivesical, one located between root of mesentery and tail of pancreas, one involving the mesentery, omentum and abdominal wall extensively and one located between liver and stomach). After critical re-evaluation of surgical reports and remote clinical history and a careful search for residual muscular tissue from the gut wall in the tumour pseudocapsule (in some cases supported by desmin immunoreactivity), it was possible to reclassify most of these cases (11/14) as either GISTs with extensive extramural growth resulting in loss of contact to the external muscle coat of the gut (8/14) or as metastases from an inoperable GIST (2/14) or from a previously resected deceptively benign tumour (1/14).

CONCLUSION

EGISTs are probably rarer than previously reported (1.5% or less in this study). We concluded that most so-called EGISTs represent apparent EGISTs that should have arisen from the outermost muscle coat, but have lost their contact to the point of origin due to extensive extramural growth pattern. From a surgical point of view, it is crucial to document and mark any focal attachment or adhesions to the gut wall noticed during surgery for an apparent EGIST. In contrast to most other neoplasms, GISTs should be defined by virtue of any degree of association with the muscularis propria (no matter how minimal), but not by localisation of the bulk of the tumour.

Intraductal papillary mucinous adenoma that arises from pancreatic heterotopia within a meckel diverticulum

Neoplasia is an unusual complication of Meckel diverticulum. Most tumors of Meckel diverticulum are neuroendocrine or mesenchymal in origin. Adenocarcinomas represent a minority of the tumors that arise in Meckel diverticulum and are generally thought to develop from either endogenous small intestinal epithelium or heterotopic gastric epithelium. Despite the presence of ectopic pancreas in a small fraction of Meckel diverticula, convincing evidence of tumors that arise from heterotopic pancreatic exocrine tissue has not been described in this setting. Intraductal papillary mucinous neoplasms are relatively uncommon tumors of pancreatic ductal epithelial cells that line the main pancreatic duct or its major side branches. We present an unusual case of an intraductal papillary mucinous neoplasm that arose in a heterotopic pancreas within a Meckel diverticulum.

Stromal tumour within a Meckel's diverticulum: CT and ultrasound findings

The incidence of tumours within a Meckel's diverticulum is 0.5-3.2%. Their pre-operative diagnosis is rare. We report a case of an incidentally found gastrointestinal stromal tumour within a Meckel's diverticulum in a patient presenting with acute appendicitis. The tumour was demonstrated pre-operatively by ultrasound and CT.