Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review

Frequency and Characteristics of Gastrointestinal Diseases in Patients With Neurofibromatosis

Background and Aim

Patients with neurofibromatosis (NF) frequently experience gastrointestinal symptoms, but the specific characteristics of these lesions are not well understood.

Methods

To investigate the prevalence and nature of gastrointestinal diseases in this population, we analyzed the gastrointestinal lesions identified through endoscopic examinations in patients with NF.

Results

We included 225 patients with NF type 1 (NF1) and 15 with NF type 2 (NF2). None of the NF2 patients underwent endoscopy. Among the NF1 patients, 27 received endoscopies, and 13 (59%) had gastrointestinal lesions. These 13 patients were predominantly male (10 males and three females), with a median age of 53 years (range: 19-76 years). The identified lesions included colorectal polyps (n = 6), gastrointestinal stromal tumors ([GIST], n = 4), subepithelial lesions (n = 3), gastric fundic gland polyps (n = 3), diffuse intestinal ganglioneuromatosis (n = 2), esophageal polyps (n = 2), a Schwann cell hamartoma (n = 1), esophageal cancer (n = 1), and a gastric hyperplastic polyp (n = 1). All GISTs and one case of diffuse intestinal ganglioneuromatosis were surgically resected. Interestingly, six out of 13 patients were asymptomatic. Additionally, all patients who required surgery were 40 years of age or older.

Conclusions

These findings suggest that routine endoscopic examinations, along with imaging techniques like computed tomography and magnetic resonance imaging, could be beneficial for the early detection of gastrointestinal lesions in NF1 patients aged 40 and above.

Life-threatening gastrointestinal bleeding in a case of neurofibromatosis 1 and gastrointestinal stromal tumour managed with surgical intervention as a case report

A 63-year-old patient with skin neurofibromas since birth was brought to emergency in a critical state due to massive bleeding per rectum. After stabilization and massive transfusion, the patient underwent Gastro-Intestinal (GI) endoscopy and abdominal computed tomography. A mass was identified in the jejunum. On laparotomy, multiple neurofibromas were seen in the jejunum. The segment with bleeding tumour was resected. Histopathology revealed benign spindle cell neoplasm, a gastrointestinal stromal tumour. The patient recovered and was discharged on day 15.

Jejunal gastrointestinal stromal tumor that developed in a patient with neurofibromatosis type 1: a case report

BACKGROUND

Neurofibromatosis type 1 (NF1) is known to be associated with the frequent occurrence of unique gastrointestinal stromal tumors (GISTs), preferably occurring in the small intestine, with no mutations in the c-kit proto-oncogene or platelet-derived growth factor receptor-alpha (PDGFRA), with a high tendency for multifocal development, indolent nature, with low proliferation activity and favorable prognosis.

CASE PRESENTATION

A woman in her forties visited her local doctor complaining of menstrual pain; a large mass was detected in her lower abdomen, and she was referred to our hospital. The patient had hundreds of skin warts and café au lait spots. The patient's mother had been diagnosed with type 1 neurofibromatosis. The patient met the diagnostic criteria for NF1 and was diagnosed with NF1. Ultrasonography showed a large heterogeneous cystic mass with various echo patterns, solid compartments and multiple septations. Magnetic resonance imaging showed a multilocular cystic mass with liquid content exhibiting various intensities, including that of blood. A small round solid mass was also observed close to the cystic tumor. Contrast-enhanced computed tomography showed that the round solid mass showed strong enhancement in the early phase, unlike the cystic tumor component. Open laparotomy revealed a multicystic exophytic tumor measuring 11.5 cm originating from the jejunal wall, 20 cm distal to the duodenojejunal flexure. A solid tumor measuring 2.1 cm was also found on the anal side of the large tumor. We resected the short segment of the jejunum, including the two lesions. Microscopic findings revealed that the cystic and solid tumors consisted of spindle-shaped tumor cells showing little atypia with a fascicular or bundle arrangement. Nuclear mitosis was scarce. Immunostaining of the tumor cells showed positive staining for KIT and DOG1 and negative staining for S100 and desmin. The NF1 patient was diagnosed with multiple GISTs accompanied by intratumoral hemorrhagic denaturation arising from the jejunum. The TNM staging was pT4N0M0, stage IIIA.

CONCLUSION

We report a case of GISTs associated with NF1 that showed a jejunal origin, multifocal development and few mitotic figures. The recurrence risk, survival prognosis and need for adjuvant chemotherapy, particularly in cases where the initial GIST exhibits a very indolent pathology in NF1-related GISTs, remain to be elucidated.

Mucinous Adenocarcinoma and Carcinoid Tumor Arising Within an Ovarian Mature Cystic Teratoma: A Case Report

The coexistence of both mucinous adenocarcinoma and carcinoid tumor within an ovarian mature cystic teratoma is extremely rare. We report a case of an 18-year-old Omani woman with a left ovarian cyst. After laparotomy with left salpingo-oophorectomy, omentectomy, and peritoneal washings, the excised cyst had the typical morphology of mature cystic teratoma with grade I mucinous adenocarcinoma and a focus of carcinoid tumor.

Portal cavernoma in type 1 neurofibromatosis: A fortuitous or causal association?

Neurofibromatosis type 1 (NF-1) is a multisystem genetic disorder affecting the NF1 tumor suppressor gene. Patients typically develop superficial (cutaneous) and internal (plexiform) neurofibromas. The latter may rarely involve the liver locating in the hilum and encasing the portal vessels, leading to portal hypertension. Vascular abnormalities (NF-I vasculopathy) are a well-recognized manifestation of NF-1. Although the pathogenesis is not well-known, NF-1 vasculopathy involves arteries of both peripheral and cerebral territories, with venous thrombosis being exceptionally reported. Portal venous thrombosis (PVT) is the leading cause of portal hypertension in childhood and has been associated with several risk factors. Nevertheless, predisposing conditions remain unknown in more than 50% of the cases. The treatment options are limited, and its management is nonconsensual in the pediatric age. We report the case of a 9-year-old boy with clinically and genetically confirmed NF-1, diagnosed with portal venous cavernoma after an episode of gastrointestinal bleeding. There were no identifiable risk factors for PVT and intrahepatic peri-hilar plexiform neurofibroma was excluded by MRI imaging. To the best of our knowledge, this is the first report of PVT in NF-1. We speculate that NF-1 vasculopathy may have been a pathogenic factor, or instead, it was a fortuitous association.

Discovery of A Polymorphic Gene Fusion via Bottom-Up Chimeric RNA Prediction

Gene fusions and their chimeric products are typically considered hallmarks of cancer. However, recent studies have found chimeric transcripts in non-cancer tissues and cell lines. In addition, efforts to annotate structural variation at large scale have found examples of gene fusions with potential to produce chimeric transcripts in normal tissues. In this report, we provide a means for targeting population-specific chimeric RNAs to enrich for those generated by gene fusion events. We identify 57 such chimeric RNAs from the GTEx cohort, including SUZ12P1-CRLF3 and TFG-ADGRG7 , whose distribution we assessed across the populations of the 1000 Genomes Project. We reveal that SUZ12P1-CRLF3 results from a common complex structural variant in populations with African heritage, and identify its likely mechanism for formation. Additionally, we utilize a large cohort of clinical samples to characterize the SUZ12P1-CRLF3 chimeric RNA, and find an association between the variant and indications of Neurofibramatosis Type I. We present this gene fusion as a case study for identifying hard-to-find and potentially functional structural variants by selecting for those which produce population-specific fusion transcripts.

KEY POINTS

- Discovery of 57 polymorphic chimeric RNAs- Characterization of SUZ12P1-CRLF3 polymorphic chimeric RNA and corresponding rearrangement- Novel bottom-up approach to identify structural variants which produce transcribed gene fusions.

Bowel intussusception and adhesive intestinal obstruction in neurofibromatosis type 1

We report the case that a patient with Neurofibromatosis type 1 experienced bowel intussusception and adhesive intestinal obstruction. Bowel intussusception was considered to be due to long intestinal tube and multiple intraabdominal lesions including gastrointestinal stromal tumors (GISTs).

Reminder for the clinician: abdominal manifestations of type 1 neurofibromatosis are not so uncommon

We describe the case of a woman in her 50s with abdominal pelvic masses suspected to be an ovarian lesion with metastases. At laparoscopy, it appeared as a possible abdominal location of neurofibromatosis type 1 (NF-1). A 50 cm of small bowel was resected to remove multiple nodular lesions. On histopathology, small bowel lesions (n=14) were all classified as GISTs. Clinicians should recognise and consider gastrointestinal manifestations of NF-1 in the diagnostic flow chart. Surgical treatment may resolve symptomatic cases and prevent local infiltration or malignant degeneration of abdominal neoplasms occurring in patients with NF-1.

Solid Primary Retroperitoneal Masses in Adults: An Imaging Approach

Mass lesions in the retroperitoneal space may be primary or secondary. Primary retroperitoneal mass lesions are relatively uncommon as compared to pathology that arises secondarily from retroperitoneal organs. These may be solid or cystic lesions. The overlapping imaging features of various solid primary retroperitoneal tumors make the diagnosis difficult, and hence, histopathology remains the mainstay of diagnosis. This paper provides a brief review of the anatomy of the retroperitoneal space and provides an algorithmic approach based on cross-sectional imaging techniques to narrow down the differential diagnosis of solid primary retroperitoneal masses encountered in the adult population.

Gastric Malignant Peripheral Nerve Sheath Tumor in Type 1 Neurofibromatosis

Gastric malignant peripheral nerve sheath tumors (MPNSTs) are extremely rare spindle cell sarcomas that arise within the peripheral nerves of the gastrointestinal tract. MPNST can present as a mass that may or may not be accompanied by obstruction or bleeding. Type 1 neurofibromatosis (NF) is an autosomal dominant genetic disorder with an incidence of 1 in 2,500-3,000. Plexiform neurofibromas in Type 1 NF can undergo a malignant transformation to MPNSTs. Approximately half of the incidence of MPNST is associated with the NF-1 gene. MPNST behaves aggressively, and radical excisional surgery is important for treatment. Recurrence and metastasis are significant, even after a radical excision. Despite multidisciplinary treatment, the five-year survival rate is only 30-50%. This paper reports the case of a 47-year-old man with Type 1 NF who presented with hemorrhage of a gastric subepithelial lesion. He underwent surgery under the suspicion of a gastrointestinal stromal tumor, but it was diagnosed as MPNST after confirming the histopathological appearance and immunohistochemical profiles. In addition, the large mass invaded the spleen and diaphragm. Radical surgery was performed, and additional chemotherapy was administered. This paper reports the experience of a patient with NF 1 with advanced MPNST discovered due to a subepithelial lesion.

Mutation of PTPN11 (Encoding SHP-2) Promotes MEK Activation and Malignant Progression in Neurofibromin-Deficient Cells in a Manner Sensitive to BRAP Mutation

Simple Summary

Germline mutations of NF1 cause neurofibromatosis type 1 (NF1), which is characterized by multiple benign peripheral nerve sheath tumors known as neurofibromas. In some individuals with NF1, plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors. Here, we applied genomic DNA sequencing to NF1-derived tumors and identified additional genetic alterations in PTPN11 (encoding Src homology region 2 domain-containing phosphatase-2 (SHP)-2) and BRAP associated with NF1 tumor malignancy. We found that the forced expression of the mutant form of SHP-2 activated the protein kinase MEK and increased tumorigenic activity in NF1 cells, and that these effects were attenuated by the forced expression of the mutant form of BRCA1-associated protein (BRAP). This suppressive action of mutant BRAP was not apparent in NF1-intact cells. Our data indicate that the combination of NF1 mutation and PTPN11 mutation drives the malignancy of NF1 cells and that SHP-2 inhibition by BRAP is a potential therapeutic strategy for NF1-associated malignant tumors.

Abstract

Germline mutations of NF1 cause neurofibromatosis type 1 (NF1) through the activation of the RAS signaling pathway, and some NF1 patients develop malignant peripheral nerve sheath tumors (MPNSTs). Here, we established subclones of the human NF1-MPNST cell line sNF96.2 that manifest increased tumorigenic activity and increased phosphorylation of the protein kinases MEK and Akt relative to the parental cells. Genomic DNA sequencing identified 14 additional heterozygous mutations within the coding regions of 13 cancer- and other disease-related genes in these subclones. One of these genes, PTPN11, encodes SHP-2, and the forced expression of the identified G503V mutant of SHP-2 increased both tumorigenic activity and MEK phosphorylation in parental sNF96.2 cells, suggesting that the combination of PTPN11 and NF1 mutations induces the pathological activation of the RAS pathway. These effects of SHP-2 (G503V) were inhibited by the coexpression of the G370A mutant of BRAP, which was also detected in the highly malignant subclones, and this inhibition was accompanied by the calpain-dependent cleavage of SHP-2 (G503V). The cleavage of SHP-2 (G503V) and suppression of MEK phosphorylation mediated by BRAP (G370A) were not detected in NF1-intact (HeLa) cells. Tumor promotion by SHP-2 (G503V) and its suppression by BRAP (G370A) may serve as a basis for the development of new treatment strategies for NF1.

Adrenal pheochromocytoma: is it all or the tip of the iceberg?

Adrenal pheochromocytoma is not always a simple retroperitoneal tumor but may be part of a more complicated condition. It often has a spectrum of complex and variable imaging features, may present as a collision tumor and composite tumor, and is associated with a variety of clinical syndromes. A comprehensive understanding of the clinical, pathological, and variable imaging manifestations of pheochromocytoma can help radiologists make an accurate diagnosis. This article reviews various special imaging features of pheochromocytoma and pheochromocytoma-related diseases.

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.

Comprehensive clinicopathologic characteristics of intraabdominal neurogenic tumors: Single institution experience

BACKGROUND

Neurogenic tumors are rare but represent an important consideration in the differential diagnosis of abdominal mesenchymal tumors. Reports on their incidence, pathological features and clinical characteristics are scarce.

AIM

To advance the overall knowledge on the histologic, immunohistochemical, clinical and radiologic characteristics of neurogenic tumors through this case series.

METHODS

An established database of a nationwide tertiary referral center, covering a 15-year period (2005 and 2020), was retrospectively re-evaluated. Diagnoses of neurogenic tumor cases were confirmed by two experts following review of the macroscopic, histological and immunohistochemical records along with findings from analysis of archived tissue sections for each included patient. Tissue microarrays were constructed for cases lacking necessary immunohistochemical studies. Clinical data and follow-up information were collected from the hospital records and the patients themselves, when available.

RESULTS

The study included 19 cases of intraabdominal neurogenic tumors, representing 12 women and 7 men, between 18 and 86 years of age (median: 51 years). Final confirmed diagnoses were 12 schwannomas, 2 diffuse submucosal neuro-fibromatoses, 2 ganglioneuromas, 2 malignant peripheral sheath nerve tumors, and 1 mucosal Schwann cell hamartoma. Sizes of the tumors were variable, with a median diameter of 4 cm; the two largest (> 10 cm) were schwannomas. The majority of cases were asymptomatic at presentation, but the most frequent symptom was abdominal pain. Gastrointestinal tract lesions were detected with endoscopy and extra-luminal lesions were detected with cross-sectional imaging. All cases were S100-positive and CD117-negative; most cases were negative for desmin, epithelial membrane antigen, smooth muscle actin and CD34. In all but 5 cases, the Ki67 proliferation index was ≤ 1%.

CONCLUSION

Re-evaluation of 19 cases of abdominal neurogenic tumors demonstrated con-siderable variability in clinicopathologic characteristics depending on location, dimension and histological features.

Small, low-grade ampullary neuroendocrine tumor presenting with metastasis and multiple synchronous tumors in a patient with neurofibromatosis type 1: a case report with literature review

Neurofibromatosis type 1 (NF1) is a tumor syndrome and one of the most common genetic disorders. Patients have an increased risk of developing neurologic and gastrointestinal (GI) neoplasms, but GI lesions are often underrecognized since most cases are asymptomatic. It is extremely rare to see multiple types of abdominal tumors synchronously in NF1. In this case, we describe a patient presenting with a small, low-grade periampullary neuroendocrine tumor (NET) that underwent endoscopic submucosal dissection and later pancreaticoduodenectomy (Whipple procedure). This led to findings of lymph node and distant metastasis of her NET, and the incidental discovery of gastrointestinal stromal tumors, extensive pancreatic intraepithelial neoplasia, and main duct and side branch intraductal pancreatic mucinous neoplasm. The synchronous presence of these lesions has not been reported in the literature.

Imaging Features of Neurofibromatosis Type 1 in the Abdomen and Pelvis

OBJECTIVE. Loss of the neurofibromatosis type 1 (NF1) tumor suppressor protein causes uninhibited activation of the RAS oncogene, which leads to tumorigenesis in patients with NF1. This case-based review discusses imaging manifestations of NF1 in the abdomen and pelvis, highlighting key genetic associations and management to elucidate features different from the general population. CONCLUSION. The spectrum of pathologic findings includes gastrointestinal tumors such as gastrointestinal stromal tumors, genitourinary lesions including urogenital neurofibromas, vascular entities such as renal artery stenosis, and less common associations like lymphoma.

Concomitant neuroendocrine tumor and gastrointestinal stromal tumor in a duodenal fine needle aspiration: A cytologic clue for neurofibromatosis type 1

The identification of two cell populations displaying different cytologic characteristics in the same fine needle aspiration (FNA), one with an epithelioid appearance and the other spindle cell morphology, is an extremely rare phenomenon and potentially represents a source of diagnostic confusion. Depending on the lineage and relationship of the two cell types, the differential diagnosis is broad and encompasses a wide spectrum of entities. The current case describes the presence of nests and clusters of neuroendocrine cells associated with rare spindle cell fragments of gastrointestinal stromal tumor (GIST) in the same fine needle aspiration of a duodenal mass. Our literature analysis revealed that such combined cytologic findings were hitherto never reported and the concurrence of well-differentiated neuroendocrine tumor (NET) and GIST is almost pathognomonic for neurofibromatosis type 1 (NF-1).

CO-OCCURRENCE OF ADRENOCORTICAL CARCINOMA AND GASTROINTESTINAL STROMAL TUMOR IN A PATIENT WITH NEUROFIBROMATOSIS TYPE 1 AND A HISTORY OF ENDOMETRIAL CANCER

Neurofibromatosis type 1 (NF-1) is an autosomal dominant inherited syndrome affecting 1 per 3000-4000 individuals. Patients with the neurofibromin gene mutation are more likely to develop malignancies. We report the case of a 57-year-old female with NF-1 who presented during her lifetime three neoplasms: endometrial cancer, adrenocortical carcinoma (ACC) and gastrointestinal stromal tumor (GIST). We describe the clinical, radiological and histopathological features of this rare condition. There have been reported only 10 cases of ACC together with NF-1 and 18 cases of ACC with other tumors. To the best of our knowledge it is the first reported case of NF-1 diagnosed with three cancers. Our report indicates the importance of careful and all-embracing care of patients with NF-1 in order to make a thorough investigation of any symptoms that might be a manifestation of a malignant disease.

Synchronous Gastrointestinal Stromal Tumor and Ampullary Neuroendocrine Tumor in Association with Neurofibromatosis Type 1: A Report of Three Cases

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disorder. The pathogenesis of NF1 is suggested to be an alteration of the NF-1 gene, which normally functions as a tumor suppressor. A mutation of NF-1 causes the development of viable tumors in various sites. On the other hand, the synchronous manifestation of a gastrointestinal stromal tumor (GIST) and neuroendocrine tumor (NET) in the background of NF1 is extremely rare. This paper reports three cases treated with surgical intervention along with the long-term follow-up results. Three patients showed synchronous ampullary NET and GIST in association with NF1 supported by postoperative histopathologic analysis. Surgical treatments, such as pancreatoduodenectomy and local excision were applied. No recurrence occurred during the postoperative follow-up period of 10, 9, and 2.7 years. Synchronous GIST and NET in the background of NF1 is extremely rare, but the possible coexistence of other tumors in NF1 patients is relatively higher than that in the general population. Furthermore, both NETs and GISTs occurring in NF1 patients tend to be smaller in size compared to that in the general population. Therefore, when NF1 patients present with vague abdominal discomfort, close attention must be paid to identifying the coexistence of other neoplasms.

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.