Multiple endocrine syndromes--a nightmare for the endocrinologic radiologist

CT- and ultrasound-characteristics of hepatic lesions in patients with multiple endocrine neoplasia syndrome. A retrospective image review of 25 cases

Introduction

Liver metastases from neuroendocrine tumors in multiple endocrine neoplasia syndrome are common (75%) and significantly impairs the prognosis. Characterisation of liver lesions in these patients is challenging, as liver metastases are difficult to differentiate from benign liver lesions such as haemangioma.

Methods

In this study we aimed to characterize the radiological findings of hepatic metastases in MEN patients. The findings of contrast-enhanced CT were considered for the main diagnosis. We retrospectively evaluated 25 patients with MEN-syndrome (10 MEN1/ 15 MEN2) including 11 men and 14 women between 28–62 years of age.

Results

Liver metastases (48%, 12/25) and hemangioma (40%, 10/25) were the most common liver lesions among our patients. The most common primary tumors in our MEN1 and MEN2 patients with liver metastases were of pancreatic neuroendocrine tumor (70%, 7/10) und medullary thyroid carcinoma (100%, 15/15) origin, respectively. CT-characteristics were grouped into three main categories, depending on contrast dynamics. The majority of hepatic metastases (75%, 14/25) are presented as multiple lesions with a slow growth in an average 5 years of follow-up-period. We were able to find a common CT pattern and categorise these for each MEN-syndrome. Hepatic metastases in MEN1 presented commonly a blurred arterial enhancement with a low portal venous enhancement and less frequently a prominent enhancement in the arterial phase, which mimics the classical haemangioma. In MEN2 the liver metastases exhibited disseminated mixed hyper- and hypo-enhanced lesions in CT-scans. Moreover, lesion calcifications are pathognomonic in MEN2. The main limitation of this study is the missing histopathological confirmation in the majority of cases.

Conclusions

In this retrospective imaging study, we were able to categorise and find a common CT pattern for hepatic lesions in patients with MEN-syndrome. In order to differentiate these lesions sufficiently, a combination of a 3-phasic CT-scan with US is required. Other liver specific imaging modalities (MRI, CEUS, SMS-PET/CT) should complement the diagnosis in individual cases.

Duodenopancreatic resections in patients with multiple endocrine neoplasia type 1

OBJECTIVE

To review the authors' 7-year experience with a surgical approach for pancreatic and duodenal neuroendocrine tumors (NETs) in patients with multiple endocrine neoplasia type 1 (MEN 1) designed to remove all gross tumor with limited complications, preserving pancreatic function.

SUMMARY BACKGROUND DATA

MEN 1 is an autosomal dominant familial neoplasia syndrome characterized by the development of NETs of the duodenum and pancreas. Some tumors are clinically insignificant or follow a benign course, although a subset pursues a malignant, lethal natural history; the risk of surgical management must be appropriate to the disease course.

METHODS

The clinical, biochemical, genetic, and pathologic data were retrospectively reviewed for 21 consecutive MEN 1 patients undergoing pancreatic resection for NETs between 1993 and 1999 at one institution. Age at operation, presenting symptoms, results of preoperative and intraoperative localization studies, major and minor complications, and pathology, including metastases, were analyzed.

RESULTS

The surgical approach was selected based on the location and size of the tumors. Five patients required pancreaticoduodenectomy, 11 patients underwent non-Whipple pancreatic resections, and 5 underwent simple enucleation of benign NETs. The incidence of regional lymph node metastases was 33%.

CONCLUSIONS

Major pancreatic procedures can be performed safely in most patients with MEN 1 and NETs. Because NETs are the most common MEN 1-related cause of death in the authors' kindreds, an aggressive surgical approach, including early intervention before malignant spread and major pancreatic resection where indicated, appears justified.

Experience with multiple endocrine neoplasia type 1 screening

Screening for multiple endocrine neoplasia type 1 (MEN1) may be conducted for a variety of reasons. The principal aims may be more or less scientific, such as early identification of the trait. Other reasons for screening comprise attempts to avoid endocrine morbidity and possibly forthcoming problems from malignant transformation, as well as attempts to identify and treat gene carriers with a clinically overt disease. Several reports have substantiated the diagnostic yield from screening efforts among MEN1 kindreds. Such increases in detection of the disease ideally should be accompanied by enhanced rates of survival in order to fully justify an unlimited search for the trait. However, studies are lacking a clearly verifying reduction of mortality from the detection of presymptomatic MEN1 individuals. While waiting for the results of survival studies in progress, the generally prevailing opinion favours widespread screening because of the evidently decreased morbidity resulting from early diagnosis of the MEN1 trait, which apparently persists even during decades of follow-up. This paper presents the clinical features of the disease and experience derived from a prospective screening programme for MEN1 detection.

Difficulties in localization and treatment of insulinomas in type 1 multiple endocrine adenomatosis (MEA)

A 15 year old girl with a family history of type 1 multiple endocrine adenomatosis presented with reversible neurological disturbances, hypoglycaemia and hyperinsulinaemia. Initial radiology was normal, but portal venous sampling suggested an insulinoma in the tail of the pancreas which was removed with conservation of the spleen. Hypoglycaemia persisted despite high doses of diazoxide and intravenous dextrose. A second laparotomy revealed a pancreatic endocrine tumour and sub-total pancreatectomy was performed. Histology revealed islet cell microadenomatosis. Hypoglycaemia persisted despite treatment with somatostatin analogues and 40% intravenous dextrose was required to maintain normoglycaemia. A possible lesion near the splenic hilum on computed tomographic scan was reported as a splenunculus although further peripheral, hepatic and portal venous sampling suggested hepatic or systemic lesions. A positron emission scan and selective visceral angiography suggested a lesion in the left upper quadrant. Acute lactic acidosis, rhabdomyolysis and renal failure supervened. Post mortem revealed the putative 'splenunculus' to be a residual insulinoma, whilst the splenic vein was thrombosed, accounting in part for discrepant venous sampling data. Hyperinsulinaemia in type 1 multiple endocrine adenomatosis may require more aggressive surgical and hormonal intervention than when dealing with solitary insulinomas. Insulinomas may mimic developmental abnormalities on computed tomographic scanning.

Surgical treatment of endocrine pancreatic lesions in MEN-1

The surgical treatment of endocrine pancreatic lesion in the multiple endocrine neoplasia syndrome type 1 (MEN-1) has remained a controversial issue. Histologic studies have revealed that the pancreatic lesions generally consist of numerous microadenomas, spread throughout the pancreas, together with occasional larger tumors. The patients may also harbor multiple, mainly gastrin secreting, duodenal microadenomas. A total pancreatectomy/duodenectomy should theoretically be needed for cure, but has not been recommended due to the associated mortality and morbidity, considering also the favorable prognosis of most MEN-1 patients. When pancreatic involvement in MEN-1 is biochemically diagnosed efforts should be made to localize the lesions by computed tomography, angiography and, in some patients, also transhepatic portal vein catheterization and venous sampling (PTP). Hypergastrinemia and the Zollinger-Ellison syndrome (ZES) generally constitute two-thirds of the clinically detected pancreatic lesions in MEN-1. Surgery may be undertaken in ZES-MEN-1 patients with focal lesions visualized by radiology or PTP in order to minimize the risk of malignant development in a gross tumor. Patients with insulin excess and hypoglucemia as well as the rare vipoma patient may, even in the absence of radiologically visualized tumors, be subjected to exploration, and these patients are usually found to harbor one or several gross tumors. The more frequent clinically silent, mainly PP-producing tumors should be removed when visualized by radiology. However, indications for surgery also have to emphasize an unusually malignant behavior in certain kindreds and patients may thus have to be explored when only biochemical data indicate the presence of pancreatic lesions. Pancreatic operations in MEN-1 should generally include a corpus and tail resection, together with enucleation of lesions in the pancreatic head, and in addition to that a careful duodenal exploration. Intraoperative ultrasound examination appears to be of considerable value by its ability to reveal also smaller lesions which may escape palpation.