Tracking Down Duodenopancreatic Malignancy

Background Malignant tumours of the duodenum are rare and often difficult to diagnose. Due to the small clinical experience with duodenal malignancies their prognosis is unknown and resection is the treatment of choice. Case report Adding to a small series of incidental tumours, we report the case of a 65-year-old patient with primary extranodal (MALT-) lymphoma of the duodenum infiltrating the pancreatic head. The patient was admitted because of anaemia and epigastric discomfort with a history of Helicobacter- pylori associated gastric ulceration. Physical examination and bloodchemical values were otherwise normal. Endoscopy revealed duodenal ulceration but the biopsies taken from the ulceration did not give any evidence of malignancy or residual Helicobacter pylori infection. But MRT showed a circular intramural tumour of the duodenum. On laparotomy a large duodenal tumour adherent to the pancreatic head was found and a Whipple procedure was performed. Conclusion Apart from describing the case of a rare lymphoproliferative disorder of the duodenum, this report illustrates the diagnostic difficulties with uncommon neoplasm's of the duodenopancreatic region and the value of MRT prior to resection of a duodenopancreatic mass.


INTRODUCTION
Malignant neoplasm's of the small bowel are rare and their prognosis is vague [1].A recent epidemiological, US-American study [2] found an average annual incidence rate of 9.9 per million people for malignant tumours of the small intestines.The incidence was higher among men than among women and was found to be overall rising and rising with age.The most common histologic subtypes in this study were carcinoid tumours (3.8/million) and adenocarcinoma (3.7/million), sarcoma (1.3/million) and lymphoma (1.1/million).Smaller series have seen adenocarcinoma [3] or lymphoma [4] ahead in incidence.Adenocarcinoma seems to be more common in industrialised countries, where intestinal lymphomas are rather rare [5].Intestinal lymphomas form a heterogeneous subgroup of malignant lymphomas currently classified in the Kiel-, or most recently in the Revised European-American Classification of Lym- phoid Neoplasm's (=REAL) [6].Intestinal B-Cell *Corresponding author.Tel." 49-621-3832225, Fax: 49-621-3833809, e-mail: stephan.samel@chir.ma.uni-heidelberg.delymphoma, most often large cell lymphoma [7], is common in the ileum [5] but rare in the duodenum and may mimic adenocarcinoma of the pancreatic head or duodenum or other neoplasm's of the duodenopancreatic region [81.
Diagnosis of tumours of the duodenopancreatic region, as it has been experienced by various authors, is often obscured by vague abdominal symptoms e.g., abdominal discomfort, nausea, vomiting or weight loss.Physical examination may reveal a palpable mass in patients with ad- vanced tumour growth.
Endoscopic diagnosis of duodenal lesions often fails because of a cryptic tumour site or an essentially submucosal or intramural tumour growth as in the presented case [9][10][11].Brush cytology may be of value in tumours of the papilla of Vater but often is not conclusive when taken from other sites [12].Biopsy specimens, too, may fail to verify a histologic diagnosis due to endoscopically not accessible tumour sites.Laboratory examinations and contrast enhanced radiographs often lack characteristic findings as well.
Modern techniques of all-in-one MRT, MRCP and MRA may help to specify the diagnosis of tumours of the duodenopancreatic region [13] and to determine resectability [14].Sensitivity of MRT is high but specificity varies with tumour site.
The case history, presented below, illustrates some of these diagnostic difficulties of charac- terising malignant tumours of the duodenopancreatic region and emphasises the value of high-quality MRT.

CASE REPORT
A 65-year-old man was admitted because of anaemia, loss of weight, fatigue and epigastric discomfort with a suspected tumour of the duodenopancreatic region.CT of the abdomen, obtained prior to admission, had shown a mass in the duodenopancreatic region, suspicious for pancreatic adenocarcinoma.
On admission the patient was pale with a haemoglobin of 8.4 g/dl.Bloodchemical values, including serum electrophoresis, immune elec- trophoresis, differential blood count, and physical examination were normal.
The patient had a history of gastric ulceration and had received eradication for Helicobacter pylori infection one year prior to admission.He was under Phenobarbital medication for posttraumatic epilepsy but had not had seizures for 10 years.He denied recent fever, loss of weight, nausea or vomiting, jaundice, changes in bowel habits or quality of stool and any other major diseases.He had been operated for bilateral inguinal hernia but did not have other abdomi- nal surgery.
On gastroduodenal endoscopy the gastroduo- denal passage appeared to be normal.An ulcer was found in the descending duodenum proxi- mal of the papilla.Mucosal biopsies from this site showed signs of chronic inflammatory ul- ceration without Helicobacter pylori infection.
An endoscopic retrograde choledochopancreatogra- phy was performed demonstrating a regular shape of bileduct and main pancreatic duct.
Contrary to the endoscopic findings, hypotonic duodenography demonstrated subtotal stenosis of the descending duodenum (Fig. 1).
MRT and MRCP were performed to further characterise the suspected tumour.MRT (Fig. 2) demonstrated a segmental circular wall thicken- ing limited to the descending duodenum.A submucosal tumour, e.g., lymphoma seemed to be the most likely diagnosis.The pancreatic head was normal in size.MRCP showed an unremarkable main pancreatic duct, excluding a pancreatic mass (Fig. 3).
Endoscopy was repeated and biopsies were taken from around the papilla of Vater.Histo- pathology of these biopsies again did not reveal any conclusive malignant findings.
On laparotomy a large duodenal tumour of circular intramural growth was found without FIGURE Hypotonic duodeno-radiography demonstrates a segmental stenosis of the descending duodenum.FIGURE 2 Longitudinal MRT scan of the upper abdomen showing a segmental circular wall thickening limited to the descending duodenum.The pancreatic head is normal in size.FIGURE 3 MRCP demonstrates an unremarkable main pancreatic duct, excluding a pancreatic mass.apparent infiltration of mucosa or serosa.The The diffuse lymphoid infiltrates contained a tumour, however, was found to infiltrate the large population of CD-20 positive cells.CD-3 papilla of Vater and the pancreatic head.Sus- positive small T-cells were present in smaller pecting malignancy a Whipple procedure was numbers and were dispersed in the B-cell pro- performed.The macroscopic inspection of the liferates.Ki67-index was low and -lightchains specimen revealed a semicircular infiltrative were restricted (Fig. 5b) in favour of &light- mass in the duodenal wall (Fig. 4).The patient chains (Fig. 5c).These findings are conclusive recovered well and was discharged 10 days after of a low grade B-cell lymphoma according to surgery.Adjuvant radiotherapy was performed the Kiel-classification scheme.The infiltration starting four weeks after surgery, of lymphoid cells with lymphofollicular hyper-Microscopic findings The tumorous mass plasia in the duodenal mucosa next to the measured 5 cm in longitudinal length and was mucosal ulceration, which merges with the located in the wall of the duodenum.The duo-blastomatous infiltration of low grade B-cell denal mucosa overlying the mass showed flat lymphoma in the underlying deeper zones of ulceration.Microscopically there was a trans- the duodenal wall, is highly suggestive of a Bmural infiltration of the entire thickness of the cell lymphoma derived from mucosa-associated duodenal wall by proliferating lymphoid cell.lymphoid tissue (=MALT) of the duodenum.These cells infiltrated the serosa and the pan-Helicobacter pylori, however, was not evident creatic parenchyma also (Fig. 5a).The papilla neither in the tumour specimen nor in the of Vater was free of blastomatous infiltrates, gastroduodenal biopsies taken preoperatively.FIGURE 4 Gross photograph of the duodenum with a segmental intramural tumour of circular growth.The papilla of Vater is indicated by a probe.

DISCUSSION
Reconsidering this case history, several questions arise: Could preoperative diagnosis been more effective, has surgery been necessary for this type of neoplastic lesion of duodenum and pancreas, and do primary (extranodal) duode- nopancreatic lymphomas belong to the group of gastric lymphomas rather than to the group of intestinal lymphomas?
The few documented cases of primary (=extranodal) duodenal lymphoma reflect the variety of histologic subtypes of B-cell-lymphoma [15-17].Lymphomas of the papilla of Vater may form another subgroup of intestinal B-cell-lymphoma [18][19][20].Lymphoma of the stomach is known to occur in the setting of chronic Helicobacter pylori gastritis.Gastric lymphomas, located in the distal stomach, may invade the duodenum [21] and may mimic primary duodenal tumours there.In the presented case, duodenal ulceration and a history of Helicobacter pylori induced gastric ulcer- ation may have been associated with the FIGURE 5 A photomicrograph of a low-power field of the tumour shows a diffuse proliferation of lymphoid cells with infiltration of the pancreatic parenchyma (left field).Medium-power fields of this lymphoma, immunostained for -lightchains (right .upperfield: negative) and for &-lightchains (right lower field: positive in B-cells with lymphoplasmocytoid differentiation) showing a lightchain restriction as an evidence for a neoplastic proliferation.pathogenesis of duodenal lymphoma.It has to remain unclear, however, whether the re- ported MALT-lymphoma represents a gastric lesion, which had skipped into the duodenum or a primary tumour.
Only little experience with the heterogeneous group of small bowel B-cell lymphomas has been gathered so far and treatment recommen- dations are still a matter of debate [22].Several studies are currently on their way to compare radiotherapy, chemotherapy, surgery and multi- modal approaches.There is only minor evidence [23], that eradication of Helicobacter pylori is beneficial in other than gastric lymphoma.Re- section still is the predominant treatment for duodenopancreatic lymphoma [24,25] as for any duodenopancreatic tumour of suspected malig- nancy, due to the lack of clinical data on medical treatment options, and, of course due to the difficulties of finding a preoperative diagnosis as well.It is another "dilemma" for surgeons [26] that the decision whether to resect or not to resect such a tumour often has to be made without a definite histopathologic diagnosis.In the presented case, a tumour of the duo- denopancreatic region was suspected but no histologic findings were obtained in the course of diagnostic procedures.Only MRT properly identified an intramural duodenal tumour.
But experience in viewing such tumours still is too limited as to provide a specific char- acterisation of rare lesions.In such cases it will be left to the surgeon to decide, whether to resect a duodenopancreatic tumour of unknown histology or not.