Intestinal tumors in neurofibromatosis 1 with special reference to fatal gastrointestinal stromal tumors (GIST)

Neurofibromatosis Type 1 Presenting as Bleeding Jejunal Gastrointestinal Stromal Tumour

Introduction

Gastrointestinal stromal tumours (GISTs) are an important, though uncommon, cause of obscure gastrointestinal bleeding and may rarely be associated with genodermatoses such as neurofibromatosis type 1 (NF1). NF1-related GISTs have unique phenotypic features compared with sporadic GISTs and may elude diagnosis due to their predilection for the small bowel.

Case Presentation

We report a case of a 45-year-old Singaporean woman with café-au-lait macules and cutaneous neurofibromas who presented with occult obscure gastrointestinal bleeding and was eventually discovered to have a bleeding jejunal GIST. This finding, considered together with her cutaneous signs, eventually led to the diagnosis of NF1.

Conclusion

Genodermatoses and their gastrointestinal complications are likely under-reported in adult Southeast Asian populations and deserve greater awareness from gastroenterologists practising in this region.

Neurofibromatosis type 1 with multiple gastrointestinal stromal tumors: A case report

BACKGROUND

Neurofibromatosis type 1 (NF1) is characterized by café-au-lait patches on the skin and the presence of neurofibromas. Gastrointestinal stromal tumor (GIST) is the most common non-neurological tumor in NF1 patients. In NF1-associated GIST, KIT and PDGFRA mutations are frequently absent and imatinib is ineffective. Surgical resection is first-line treatment.

CASE SUMMARY

A 56-year-old woman with NF1 was hospitalized because of an incidental pelvic mass. Physical examination was notable for multiple café-au-lait patches and numerous subcutaneous soft nodular masses of the skin of the head, face, trunk, and limbs. Her abdomen was soft and nontender. No masses were palpated. Digital rectal examination was unremarkable. Abdominal computed tomography was suspicious for GIST or solitary fibrous tumor. Laparoscopy was performed, which identified eight well-demarcated masses in the jejunum. All were resected and pathologically diagnosed as GISTs. The patient was discharged on day 7 after surgery without complications. No tumor recurrence was evident at the 6-mo follow-up.

CONCLUSION

Laparoscopy is effective for both diagnosis and treatment of NF1-associated GIST.

Unusual presentation of GIST associated with type 1 neurofibromatosis: A case report

INTRODUCTION AND IMPORTANCE

Type 1 neurofibromatosis (NF1) is an autosomal dominant disorder caused by NF1 gene mutation, which is associated with several types of tumors. GIST is an intestinal stromal tumor arising from interstitial cells of Cajal in the intestine. GIST is one of the neoplasms seen in NF1 and usually affects elderly individuals with a median age around 60-65 years but rarely occur in children, adolescent and young adults.

CASE PRESENTATION

An 18-year-old male patient presented to our hospital with abdominal swelling of one-year duration. He also has multiple skin nodules and café au lait spots all over his body. Objectively, the abdomen is grossly distended; with a palpable non-tender mobile mass above the umbilicus measuring 20 × 15 cm. CT imaging of the abdomen and histologic examination of the skin lesion was done. The diagnosis of GIST was made and surgical resection followed by adjuvant therapy with imatinib was given.

CLINICAL DISCUSSION

Patients who have a gene mutation in NF 1 have a high probability (7 %) of developing GIST and mostly occur in the small intestine, whereas our finding was solitary GIST localized to the stomach. NF 1-associated GISTs are very rare and account for <5 % of all GISTs. The standard therapy for GIST is surgical resection of the tumor. Targeted therapy with tyrosine kinase inhibitors is an effective adjuvant therapy in patients harboring KIT/PDGFRA mutation.

CONCLUSION

The incidence of GIST is higher in NF1 patients than in the general population. The definitive diagnosis of GISTs preoperatively is usually challenging and is usually confirmed by immunohistochemistry. NF1-associated GISTs are mainly treated with surgery and have limited response to tyrosine kinase inhibitors.

Challenges in the management of metastatic gastrointestinal stromal tumor in a patient with neurofibromatosis type 1: a case report

BACKGROUND

Neurofibromatosis type 1 is an inherited cancer predisposition syndrome that is caused by a mutation in the NF1 gene that encodes neurofibromin. Patients with neurofibromatosis type 1 have a higher risk of gastrointestinal stromal tumor. This study reports the case of a patient with gastrointestinal stromal tumor who was later diagnosed to have neurofibromatosis type 1 and, unlike usual features, had some uncommon features such as occurrence at an early age and unusual site of origin.

CASE

We report the case of a 29-year-old Indian female diagnosed to have gastrointestinal stromal tumor originating from the greater curvature of the stomach. Gastrointestinal stromal tumor was wild type, negative for c-kit and platelet-derived growth factor receptor, and had an aggressive clinical course not responding to oral tyrosine kinase inhibitors. On later evaluation, we found that the patient had germline mutation in NF1. This case has some unusual features compared with gastrointestinal stromal tumor cases reported in neurofibromatosis type 1. Firstly, the age of onset for gastrointestinal stromal tumor in neurofibromatosis type 1 is earlier in our case compared with previous cases reported in literature. Secondly, the site of occurrence is in the stomach, without involving other parts of the intestine. Gastrointestinal stromal tumor in neurofibromatosis type 1 is usually multifocal, and small intestine is the common site of occurrence. When occurring in the stomach, it is usually associated with other lesions in the small intestine. Lastly, the clinical course is aggressive compared with previous case reports and series.

CONCLUSION

Our patient had germline NF1 mutation and cutaneous stigmata of neurofibromatosis. Our patient had unicentric gastrointestinal stromal tumor occurring at younger age and involving greater curvature of the stomach, with spindle cell type histology and high-risk features. If gastrointestinal stromal tumor occurs at young age, we should look into neurocutaneous markers.

Plexiform fibromyxoma: Review of rare mesenchymal gastric neoplasm and its differential diagnosis

Plexiform fibromyxoma (PF) is a very rare mesenchymal neoplasm of the stomach that was first described in 2007 and was officially recognized as a subtype of gastric mesenchymal neoplasm by World Health Organization (WHO) in 2010. Histologically, PF is characterized by a plexiform growth of bland spindle to ovoid cells embedded in a myxoid stroma that is rich in small vessels. The lesion is usually paucicellular. While mucosal and vascular invasion have been documented, no metastasis or malignant transformation has been reported. Its pathogenesis is largely unknown and defining molecular alterations are not currently available. There are other mesenchymal tumors arising in the gastrointestinal tract that need to be differentiated from PF given their differing biologic behaviors and malignant potential. Histologic mimics with spindle cells include gastrointestinal stromal tumor, smooth muscle tumor, and nerve sheath tumor. Histologic mimics with myxoid stroma include myxoma and aggressive angiomyxoma. Molecular alterations that have been described in a subset of PF may be seen in gastroblastoma and malignant epithelioid tumor with glioma-associated oncogene homologue 1 (GLI1) rearrangement. The recent increase in publications on PF reflects growing recognition of this entity with expansion of clinical and pathologic findings in these cases. Herein we provide a review of PF in comparison to other mesenchymal tumors with histologic and molecular resemblance to raise the awareness of this enigmatic neoplasm. Also, we highlight the challenges pathologists face when the sample is small, or such rare entity is encountered intraoperatively.

Circulating free DNA in the plasma of individuals with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant syndrome whose characteristic manifestations include benign neurofibromas, yet NF1 is also associated with a high risk of cancer. Measurements of circulating free plasma DNA (cfDNA) are gaining wider applicability in cancer diagnostics, targeting of therapy, and monitoring of therapeutic response. Individuals with NF1 are likely to be followed up using this method, but the effects of NF1 and neurofibromas on cfDNA levels are not known. We studied peripheral blood samples from 19 adults with NF1 and 12 healthy controls. The cfDNA was isolated from plasma with QIAamp Circulating Nucleic Acid Kit and quantified using the Qubit 2.0 Fluorometer. The cfDNA concentration of each sample was normalized relative to the plasma protein concentration. The normalized median concentration of cfDNA in plasma was 19.3 ng/ml (range 6.6-78.6) among individuals with NF1 and 15.9 ng/ml (range 4.8-47.0) among controls (p = .369). Individuals with NF1 who also had plexiform neurofibroma (pNF) showed non-significantly elevated cfDNA concentration compared to individuals with NF1 and without known pNF (median 25.4 vs. 18.8 ng/ml, p = .122). The effect of NF1 on cfDNA seems to be relatively small and NF1 is therefore unlikely to hamper the use of cfDNA-based assays.

Secondary Sarcomas: Biology, Presentation, and Clinical Care

Secondary sarcomas are a subset of sarcomas that occur in patients with prior cancer diagnoses and are associated with environmental or genetic factors. Although secondary sarcomas are rare in general, there are predisposing factors that can substantially increase this risk in certain populations. Herein, we review the environmental factors with the strongest association of sarcoma risk, including chemical exposure, certain viruses, cytotoxic and immunosuppressive agents, chronic edema, and radiation exposure. Additionally, the most common genetic disorders that carry a predisposition for sarcoma development will be discussed, including hereditary retinoblastoma (RB), Li-Fraumeni syndrome (LFS), neurofibromatosis type 1 (NF1), and DICER1 syndrome. Although treatment does not generally differ for sporadic versus secondary sarcomas, awareness of the risk factors can alter therapeutic strategies to minimize risk, aid prompt diagnosis by increasing clinical suspicion, and allow for appropriate surveillance and genetic counseling for those patients with cancer predisposition syndromes.

Intestinal tumors in neurofibromatosis 1 with special reference to fatal gastrointestinal stromal tumors (GIST)

Background

Type 1 neurofibromatosis (NF1) is a genetic tumor predisposing Rasopathy. NF1 patients have an increased risk for developing benign and malignant tumors, but the occurrence of intestinal tumors has not been investigated at the population level.

Methods

In this retrospective register‐based total population study, diagnoses of gastrointestinal tract tumors were retrieved from the Finnish Care Register for Health Care for 1,410 NF1 patients and 14,030 reference persons. We also reviewed the death certificates of 232 NF1 patients who died during years 1987–2013, and specifically searched for diagnosis of gastrointestinal stromal tumor (GIST).

Results

The register analysis revealed an increased overall hazard ratio (HR) of 2.6 (95% CI 1.9–3.6) for intestinal tumors in NF1 compared to general population. The highest HR of 15.6 (95% CI 6.9–35.1) was observed in the small intestine. The focused analysis of NF1 death certificates and GISTs demonstrated that the GIST was the primary cause of death in seven patients.

Conclusion

This study emphasizes the need for careful evaluation of NF1 patients with gastrointestinal complaints. The challenge in diagnosis is that the tumors preferably occur at the small intestine, which is difficult target for diagnostic procedures. We also show that the NF1 GISTs may lead to fatal outcome despite of benign histopathological findings at the time of the diagnosis.