Association of GIST and somatostatinoma in a patient with type-1 neurofibromatosis: is there a common pathway?

The gene diagnosis of neurofibromatosis type I with headache as the main symptom: A case report and review of the literature

Neurofibromatosis type I (NF1) is an autosomal dominant disease. Some NF1 patients experience atypical clinical manifestations, genetic testing is not widely available, and the types of mutations vary; thus, they are prone to misdiagnosis and missed diagnosis. Although headache is not included in the diagnostic criteria for NF1, the incidence of headache in NF1 patients is not low. We report an NF1 family in which the proband presented with prominent headache and atypical clinical presentation, with limited skin pigmentation. We identified a frameshift mutation (c.1541_1542del, p. Q514Rfs*) in the NF1 gene by whole-exome sequencing of this family, and the patients were diagnosed with NF1. We hope to attract the attention of clinicians to these patients and improve genetic testing as soon as possible to increase the diagnosis rate.

Pancreatic Gastrinoma, Gastrointestinal Stromal Tumor (GIST), Pheochromocytoma, and Hürthle Cell Neoplasm in a Patient with Neurofibromatosis Type 1: A Case Report and Literature Review

BACKGROUND Neurofibromatosis type 1 (NF1) is a multi-tumor syndrome in which affected patients develop malignancies that are rare in the overall population, such as tumors of neural or endocrine origin. CASE REPORT A 67-year-old woman with a clinical diagnosis of NF1 presented with abdominal pain and pneumoperitoneum. She underwent small-bowel resections for a perforated jejunal lesion and a second lesion in the ileum; pathology showed a neurofibroma at the site of the perforation and a 1-cm low-grade GIST, respectively. Additional staging with cross-sectional imaging identified a 3.7-cm pancreatic head mass and a 1.7-cm left adrenal mass; biochemical studies revealed elevated serum gastrin and urinary free metanephrines and catecholamines consistent with pheochromocytoma. Initial surgical management was a left posterior retroperitoneoscopic adrenalectomy. Postoperatively, gallium-68-DOTATOC PET/CT showed uptake in the pancreatic head and a 28-mm left thyroid nodule. Months later, she had an open pancreaticoduodenectomy. Pathology showed pheochromocytoma and a low-grade (G1) gastrinoma involving 2/8 peripancreatic lymph nodes (pT3pN1M0), respectively. Fine-needle aspiration biopsy of the thyroid nodule showed features consistent with a Hürthle cell neoplasm. Genetic testing identified a pathogenic mutation in NF1 and no mutations in BRCA1/2, CDC72, MEN1, or PALB2. The patient continues surveillance, with no evidence of recurrent disease. CONCLUSIONS We report the fifth case of gastrinoma associated with NF1 and the first to arise from the pancreas. This case of a pancreatic neuroendocrine tumor was associated with multiple additional neoplasms. Neuroendocrine tumors found in NF1 should raise suspicion of other malignancies.

When should genetic testing be performed in patients with neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a heterogenous group of tumours arising from neuroendocrine cells in several sites around the body. They include tumours of the gastroenteropancreatic system, phaeochromocytoma and paraganglioma and medullary thyroid cancer. In recent years, it has become increasingly apparent that a number of these tumours arise as a result of germline genetic mutations and are inherited in an autosomal dominant pattern. The number of genes implicated is increasing rapidly. Identifying which patients are likely to have a germline mutation enables clinicians to counsel patients adequately about their future disease risk, and allows for earlier detection of at-risk patients through family screening. The institution of screening and surveillance programmes may in turn lead to a major shift in presentation patterns for some of these tumours. In this review, we examine the features which may lead a clinician to suspect that a patient may have an inherited cause of a NET and we outline which underlying conditions should be suspected. We also discuss what type of screening may be appropriate in a variety of situations.

Somatostatin-Immunoreactive Pancreaticoduodenal Neuroendocrine Neoplasms: Twenty-Three Cases Evaluated according to the WHO 2010 Classification

BACKGROUND/OBJECTIVE

Neuroendocrine neoplasms of the pancreas and duodenum with predominant or exclusive immunoreactivity for somatostatin (pdSOMs) are rare, and knowledge about tumour biology, treatment, survival and prognostic factors is limited. This study aims to describe clinical, pathological and biochemical features as well as treatment and prognosis of pdSOMs.

DESIGN

Twenty-three patients with pdSOM (9 duodenal, 12 pancreatic and 2 unknown primary tumours) were identified from our prospective neuroendocrine tumour database, and data according to the study aims were recorded.

RESULTS

Among the 9 patients with duodenal SOM, the male/female ratio was 4/5. All males and 1 female had neurofibromatosis type 1. Seven patients had stage 1A/B and 2 had stage 2B disease. The Ki-67 index was 1-5% (median 2%). Plasma somatostatin was elevated in the patients with 2B disease. Of the 14 patients with pancreatic SOM or an unknown primary tumour, the male/female ratio was 2/12. One male had multiple endocrine neoplasia type 1. Five had stage 1A/2B and 9 had stage 4. The Ki-67 index was 1-40% (median 7%). Plasma somatostatin was elevated in 7 patients. Patients reported symptoms related to the somatostatinoma syndrome, but none fulfilled the criteria for a full syndrome. Primary tumour in the pancreas, metastatic disease at diagnosis and higher tumour grade were all associated with significantly poorer survival.

CONCLUSION

None of the patients with pdSOM presented with the full somatostatinoma syndrome. Prognostic factors are localisation of the primary tumour, dissemination and tumour grade. A Ki-67 index of 5% may discriminate the course of the disease.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Pancreatic somatostatinoma with obscure inhibitory syndrome and mixed pathological pattern

Somatostatinoma is a very rare neuroendocrine tumor that originates from D cells and accounts for less than 1% of all gastrointestinal endocrine tumors. The duodenum is the most frequent site for this tumor, followed by the pancreas. We here describe a 46-year-old Chinese woman who developed pancreatic somatostatinoma presenting with the characteristic "inhibitory" syndrome, but the symptoms were obscure and seemingly uncorrelated. This case is also unique for its large tumor size and mixed pathological pattern. Distal pancreatectomy was performed, and the patient has remained well since operation. As the syndromes of somatostatinoma may be obscure and atypical, clinicians should review all clinical findings to obtain an accurate diagnosis. Aggressive surgery is preferred to improve the survival.

Vasculopathic changes, a somatostatin-producing neuroendocrine carcinoma and a jejunal gastrointestinal stromal tumor in a patient with type 1 neurofibromatosis

A 36-year-old male with neurofibromatosis type 1 (NF-1) presented with symptoms of obstructive jaundice. Imaging showed a periampullary mass, which on endoscopic retrograde cholangiopancreatography biopsy proved to be a somatostatinoma. A Whipple's procedure was performed and a somatostatinoma of the duodenum was confirmed. In addition, the patient had a gastrointestinal stromal tumor (GIST) of the jejunum with accompanying hyperplasia of interstitial cells of Cajal. The somatostatinoma was histologically characteristic with pseudoglandular and solid patterns together with psammoma bodies and lymphovascular invasion. The GIST did not display mutations in c-kit or platelet-derived growth factor receptor genes. The novel finding in this case was the presence of several vessels in the submucosa and muscularis propria of the duodenum displaying prominent intimal hyperplasia and in keeping with so-called neurofibromatosis-associated vasculopathy. These abnormal vessels were within and close to the somatostatinoma only and were not found away from the tumor. It is thought that the vasculopathy is related to NF-1 with abnormal neurofibromin possibly playing a role.