Routine Excision, Rare Diagnosis: Solitary Neurofibroma Prompting NF1 Screening in an Adolescent

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen's disease, is an autosomal dominant disorder characterized by multiple café-au-lait macules and cutaneous neurofibromas. Although neurofibromas are common in NF1, involvement of the urinary tract is rare, with the bladder being the most frequently affected site. Urachal neurofibromas are extremely rare, and their diagnosis and management remain challenging due to nonspecific imaging characteristics and their often asymptomatic presentation.We report the case of a 30-year-old man with clinical features of NF1 in whom a 5-cm mass at the bladder dome was incidentally identified on MRI performed during evaluation for spinal cord symptoms. Imaging revealed a cone-shaped mass in the urachal region, and cystoscopy showed no mucosal abnormalities. Urinalysis and urine cytology were unremarkable. A transabdominal needle biopsy confirmed the diagnosis of a neurofibroma. Given the tumor’s size (>5 cm) and deep-seated location in the trunk, both known risk factors for malignant transformation, surgical excision was performed, including resection of the urachus and bilateral umbilical ligaments. Histopathological analysis confirmed a plexiform neurofibroma consistent with NF1. The postoperative course was uneventful, with no evidence of recurrence during 36 months of follow-up.This case highlights the rare presentation of a urachal plexiform neurofibroma in a patient with NF1. To reduce the potential risk of malignant transformation associated with plexiform neurofibromas larger than 5 cm and located in deep trunk regions, accurate diagnosis and timely surgical intervention are essential, even in asymptomatic cases.

Understanding the biological pathways critical for common neurofibromatosis type 1 (NF1) peripheral nerve tumours is essential, as there is a lack of tumour biomarkers, prognostic factors and therapeutics. We used gene expression profiling to define transcriptional changes between primary normal Schwann cells (n = 10), NF1-derived primary benign neurofibroma Schwann cells (NFSCs) (n = 22), malignant peripheral nerve sheath tumour (MPNST) cell lines (n = 13), benign neurofibromas (NF) (n = 26) and MPNST (n = 6). Dermal and plexiform NFs were indistinguishable. A prominent theme in the analysis was aberrant differentiation. NFs repressed gene programs normally active in Schwann cell precursors and immature Schwann cells. MPNST signatures strongly differed; genes up-regulated in sarcomas were significantly enriched for genes activated in neural crest cells. We validated the differential expression of 82 genes including the neural crest transcription factor SOX9 and SOX9 predicted targets. SOX9 immunoreactivity was robust in NF and MPSNT tissue sections and targeting SOX9 – strongly expressed in NF1-related tumours – caused MPNST cell death. SOX9 is a biomarker of NF and MPNST, and possibly a therapeutic target in NF1.

Background: Plexiform neurofibroma (PN) is a subtype of neurofibroma that is rather uncommon in the clinic. Plexiform neurofibroma is usually associated with neurofibromatosis type I (NF1). Only very few patients have isolated PN, which means they have neither NF1 signs nor relevant family history. Solitary PN is extremely rare. There have been no instances of finger back PN or solitary PN all around the world, which could lead to misdiagnosis, missed diagnosis, and mistreatment. Case presentation: We present a rare case of a 50-year-old middleaged woman who experienced numerous postoperative recurrences of painful tumors on the dorsal side of her proximal middle finger on her right hand. Following surgery, the pathology diagnosis was PN. The pathology diagnosis after surgery was PN. After the operation, the wound healed in stage I, and the outcomes were satisfactory. Conclusion: In the dorsal finger nerve, solitary PN can occur. As a result, the differential diagnosis of NF1, PN, and isolated PN as hand masses is crucial for early diagnosis and rational treatment, especially for masses with pain associated with neuropathy should be considered as a possibility of this disease. The lesion may be invasive or multiple in character, Keep a close eye on cautious probing throughout the surgery. To reduce recurrence, to avoid further deterioration, and to alleviate patients’ agony and psychological strain, the lesion tissue must be entirely removed. Keywords: Plexiform neurofibroma; Solitary plexiform neurofibroma; Neurofibromas; Recurrence; Case report.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a human autosomal dominant disorders that affects approximately 1 in 3,500 individuals worldwide. The most common features of NF1 are pigmentary abnormalities, such as cafe-au-lait macules, skinfold freckling, Lisch nodules and cutaneous and plexiform neurofibromas (PNs). These signs are age-dependent and present high variability in penetrance and expressivity even between affected members of a family. NF1 is the most common cancer predisposing syndrome affecting the nervous system. Glioma is the most common central nervous system neoplasia in NF1 patients: 15-20% NF1 children develop low grade optic gliomas. PNs occur in 30% of NF1 patients in peripheral nervous system. Patients with PNs have a 20-fold higher risk of developing malignant peripheral nerve sheath tumours (MPNSTs) than other NF1 patients. NF1 is caused by mutations in the neurofibromin gene encoding a negative regulator of Ras guanosine triphosphate (GTP)ase proteins: for this reason is considered a tumor suppressor gene. Mutation detection in the NF1 gene is complex, due to the large size of the gene (>350 kb), the presence of pseudogenes, the lack of hot spots, and the great variety of possible mutations. Hence, the clinical and molecular diagnosis of NF1 may be challenging and its fine-tuning is desirable. METHODS: During 2003-2013 NF1 mutation analysis of genomic DNA was performed in 458 patients using the multiplex ligation-dependent probe amplification (MLPA) to look for deletions or insertions located inside the NF1 gene. Subjects who tested negative for MLPA were investigated using denaturing high pressure liquid chromatography (DHPLC) and sequencing DNA. RNA-based cDNA-PCR sequencing was used in a limited group of patients. RESULTS: 299 of 458 patients were diagnosed according to NIH criteria. 54% were children and about 53% of all NF1 patients were found to have sporadic mutations. We identified 197 single mutations and more than 57% were novel. This genetic protocol permitted us to find mutations in 210 of 299 of clinically diagnosed patients (detection rate: 70%). To improve such detection rate we have recently developed a sensitive, integrated genetic protocol using MLPA and RNA-based cDNA-PCR sequencing. This protocol was validated in a cohort of 33 blood samples from NF1 patients with complete NF1 features, identifying the mutations in 30 cases (91% detection rate). CONCLUSIONS: These data suggest that integrated DNA/RNA-based protocols can improve detection rate in patients suspected to have NF1.

Neurofibromatosis type 1 (NF1) is the most commonly inherited autosomal dominant disorder in humans. NF1 patients have increased risk for gastrointestinal stromal tumors (GISTs). A Meckel's diverticulum (MD) represents a persistent embryonic omphalomesenteric duct characterized as a true diverticulum located near the ileocecal valve. We report a unique clinical case whereby a patient with NF1 developed a GIST within a MD. An adolescent male with NF1 presented with persistent lower abdominal pain. Clinical evaluation demonstrated a large pelvic mass. In the operating room, the mass was noted to emerge from a MD. Final pathology demonstrated a GIST with negative margins and CD117 positivity. Patients with NF1 are at increased risk for mesenchymal tumors including malignant peripheral nerve sheath tumors. GISTs are the most important and frequent non-neurological malignancy in NF1 and develop in ∼7% of NF1 patients. GISTs tend to be multifocal in NF1; however, they rarely occur within a Meckel's diverticula. Our case represents a rare case of a patient with NF1 who developed a symptomatic GIST within a MD. We recommend utilizing laparoscopy to determine resectability and clarify the diagnosis in this unique patient population who are at risk for multiple neoplasms.

Our case report describes an uncommon occurrence of a solitary plexiform neurofibroma in the salivary gland, which is generally associated with neurofibromatosis-1 (NF-1) but, in this case, arose independently. A 6-year-old girl presented with a painless, progressively enlarging mass in the right parotid region over a span of five years. Histopathological analysis revealed a variety of cellular elements, such as Schwann cells, perineurial cells, axons, and fibroblasts, with S100 immunohistochemistry confirming the diagnosis. This case highlights the importance of identifying solitary plexiform neurofibromas in the salivary gland, even without NF-1, and stresses the need for prompt diagnosis and treatment for optimal management.

In core needle biopsy (CNB) often the histological grade of invasive breast carcinoma is under-estimated due to heterogeneity of epithelial component. Stroma is relatively homogenous throughout the tumor and strong CD10 stromal positivity is proposed to be associated with high tumor grade. The aim of this work was to study the expression of CD10 in stromal cells of invasive carcinoma of breast, no specific type (NST) in CNB specimens, and analyze its association with final histological grade and lymphovascular invasion (LVI). A total of 50 cases of invasive carcinoma of breast, NST were studied for 18 months. CNB specimens were graded according to modified Scarff-Bloom-Richardson (SBR) system and CD10 positivity was assessed in stromal cells. Mastectomy specimens were also similarly graded. Relation of stromal CD10 positivity with histological grading and LVI was studied. Associations between the variables were studied by Chi-square test. A value of P < 0.05 was considered to be statistically significant. On CNB 46% patients had a grade 2 tumor, followed by 30% grade 3 and 24% grade 1 tumor. Strong CD10 positivity was seen in 40% cases, 32% showed weak positivity and 28% were negative for CD10 in stromal cells in CNB specimen. On evaluation of mastectomy specimen 48% of the patients had a grade 2 tumor, followed by 40% grade 3 tumor and 12% grade 1 tumor. Strong CD10 positivity was found to be significantly associated with final grade 3 tumor (P < 0.001) and LVI (P = 0.005). There was underestimation of histological grade on CNB, while strong stromal CD10 positivity in CNB was significantly associated with final grade 3 tumor and LVI.

1. Mustafa Tekin, MD* 2. Joann N. Bodurtha, MD, MPH† 3. Vincent M. Riccardi, MD‡ 1. 2. *Clinical Genetics Fellow. 3. 4. †Associate Professor of Human Genetics, Pediatrics, Obstetrics and Gynecology, Virginia Commonwealth University/Medical College of Virginia Hospitals, Richmond, VA. 5. ‡President, The Neurofibromatosis Institute, La Crescenta, CA. Objectives After completing this article, readers should be able to: 1. Define cafe au lait spots typical of neurofibromatosis type 1 (NF1) and describe their frequency and variability in the normal population. 2. List three or more genetic disorders other than NF1 that are associated with cafe au lait spots. 3. Summarize three or more clinical manifestations and molecular bases of NF1 and NF2. 4. List the diagnostic criteria for NF1. 5. Summarize clinical findings of genetic disorders other than NF1 associated with cafe au lait spots. Every pediatrician faces the challenge of deciding if a patient who has cafe au lait (CAL) spots has an underlying genetic condition. CAL spots typical of neurofibromatosis type 1 (NF1) are discrete, round or oval, uniformly hyperpigmented skin patches. Their color varies from light to dark brown, and the border may be smooth or irregular. They usually are smaller in newborns, enlarge as children get older, and are less prominent in adults. The histologic basis of CAL spots is increased melanin content, with the presence of giant melanosomes in both melanocytes and basal keratinocytes and no melanocytic proliferation. The giant melanosomes in CAL spots are not unique to NF1; they can be seen in unaffected skin of adults who have NF1 and occasionally in normal skin of healthy individuals. Therefore, the presence of giant melanosomes is not helpful for diagnosing NF1. The frequency and number of CAL spots vary in the general population according to ethnic background and age. Sometimes otherwise healthy children who have red hair and often are of Irish or Welsh background have multiple areas of patchy hyperpigmentation. Similarly, multiple patchy areas of hyperpigmentation can occur in healthy children who have mixed ethnic backgrounds in which two parents have very different skin colors. CAL spots were noted in 0.3% of Caucasians and 18% of African-Americans …

Background . Neurofibromatosis type 1 (NF1) is a genetic disorder that is characterized by multiple light brown patches of skin (café-au-lait spots) and neurofibromas. It can lead to an increased risk of malignant tumors, cognitive impairment, and skeletal abnormalities. NF1 is caused by heterozygous mutations in the NF1 gene, and identifying the specific mutation can form the basis for pathogenetic treatment of tumor syndrome. Several studies indicate that patients with the NF1 in-frame deletions tend to have a milder form of the disease that is characterized by the absence of neurofibromas. the purpose of the study was to identify in-frame deletions in the NF1 gene in patients from the Republic of Bashkortostan as well as to characterize the clinical symptoms of NF1 in this group of patients. Material and Methods . An analysis of outpatient records of NF1 patients from the Republic of Bashkortostan was conducted, along with an objective clinical examination of the patients and DNA sequencing to identify in-frame deletions in the NF1 gene. Twenty-six patients (12 females and 14 males) aged 3 to 69 years were studied. Results . The retrospective analysis of outpatient records and examination of NF1 patients showed the NF1 incidence of 1:7403.6 people. Two in-frame deletions in the NF1 gene were identified in 6 patients with NF1 from 3 unrelated families: NF1:NM_000267.3:exon21:c.2674_2679del:p. S892_K893del; NF1:NM_000267.3:exon27:c.3526_3528delAGA:p.Arg1176del. The clinical manifestations of NF1 in patients with identified mutations and their comparative characteristics with all NF1 patients in the Republic were described. In the general group of NF1 patients from the Republic, a rarer detection of neurofibromas and malignant tumors, optic nerve gliomas, and cognitive impairment was revealed. Conclusion . In patients with NF1 from the Republic of Bashkortostan with in-frame deletions in the NF1 gene, no brain cysts or tumors, plexiform neurofibromas, and optic nerve gliomas were detected. Although the mutations we identified have not previously been described in the scientific literature, our analysis of clinical features is consistent with the findings of other authors regarding the presence of phenotypic correlations with in-frame deletions.

BACKGROUNDGastrointestinal stromal tumors (GISTs) associated with neurofibromatosis are uncommon compared to their gastrointestinal counterparts. Patients with neurofibromatosis type 1 (NF-1) have an increased risk of developing gastrointestinal tumors, including rare types such as GIST.CASE SUMMARYA 60-year-old male Chinese patient was diagnosed with NF-1 10 years ago and presented with upper abdominal discomfort and black stools. Endoscopic ultrasonography and an enhanced abdominal computed tomography scan revealed a mass located 4 cm from the muscular layer of the descending duodenum. A 59-year-old Chinese woman who was diagnosed with NF-1 25 years ago presented with sudden unconsciousness and black stools. Multiple masses in the duodenum were noted by echogastroscopy and an enhanced abdominal computed tomography scan. Both patients presented with cutaneous neurofibromas. The histologic examination of tumors from both patients revealed spindle cells and low mitotic activity. Immunohistochemically, the tumor cells showed strong positivity for KIT (CD117), DOG-1, CD34, and Dehydrogenase Complex Subunit B, and negativity for SMA, desmin, S-100, and β-catenin. None of the six tumors from two patients had KIT exon 9, 11, 13, or 17 or platelet-derived growth factor receptor α exon 12 or 18 mutation, which is a typical finding for sporadic GISTs. None of the six tumors from the two patients had a BRAFV600E mutation. The patients were alive and well during the follow-up period (range: 0.6-5 yr).CONCLUSIONThere have been only a few previous reports of GISTs associated with NF-1. Although GISTs associated with NF-1 have morphologic and immunohistochemical similarities with GISTs, the pathogenesis, incidence, genetic background, and prognosis are not completely known. A medical history of NF-1 in a patient who has gastrointestinal bleeding or anemia and an intra-abdominal mass with nonspecific computed tomography features may help in diagnosing GIST by virtue of the well-known association of these two entities. Molecular genetic studies of cases indicated that GISTs in NF-1 patients have a different pathogenesis than sporadic GISTs.

Neurofibromatosis type 1 (NF1), a common autosomal dominant neurogenetic disorder affecting 1 in 4000 individuals worldwide, results from functional inactivation of the 17q11.2-located NF1 gene. Plexiform neurofibroma (PNF) is a congenital benign tumour present in 30-50% of NF1 patients, which in about 10-15% of cases, can develop into a malignant peripheral nerve sheath tumour (MPNST). This study aimed to characterise the NF1 germline and somatic mutations associated with such tumours by DNA analysis in 51 PNFs resected from 44 unrelated NF1 patients. Germline mutations were identified in 35 patients, of which 21 were novel. Somatic NF1 mutations were found in 29 PNF DNAs, which included 9 point mutations, 5 being novel, and 20 tumour DNA samples exhibiting, either loss of heterozygosity (LOH) of the NF1 gene region (16 tumours), or complete or partial NF1 gene deletions analyzed by multiplex ligation-dependent probe amplification (MPLA) analysis. The type of NF1 germline mutations detected in patients with PNF were similar to those detected in most NF1 patients. LOH of the NF1 gene region, as identified by marker analysis and/or MLPA, was detected in only 20/29 (69%) PNFs, compared to the >90% LOH previously found in MPNST. This systematic analysis of the NF1 germline and somatic mutations associated with PNF development suggest that in most such tumours neither the NF1 somatic mutation type, nor its gene location, is influenced by the underlying NF1 germline mutation. Evidence for LOH involving the TP53 gene identified in the PNFs is also reported for the first time.

Neurofibroma is an uncommon benign tumor of the oral cavity derived from the cells that constitute the nerve sheath neurofibromatosis type 1 (NF1), also known as von Recklinghausen's disease, is the most common type of neurofibromatosis and accounts for about 90% of all cases. It is one of the most frequent human genetic diseases, with the prevalence of one case in 3,000 births. Neurofibroma is seen either as a solitary lesion or as part of the generalized syndrome of neurofibromatosis. The solitary form does not differ from the disseminated form or the multiple form of the disease, except that systemic and hereditary factors present in the disseminated form are absent in the solitary type. Oral cavity involvement by a solitary and peripheral plexiform neurofibroma in patients with no other signs of neurofibromatosis is uncommon. The expressivity of NF1 is extremely variable, with manifestations ranging from mild lesions to several complications and functional impairment. Oral manifestations can be found in almost 72% of NF1 patients. This is a case report of a 40-year-old lady with a history of multiple faint rounded densities in the skin, chest pain occasionally since 8 months and breathlessness since 1 year and swelling of the right side of the angle of the mandible with limited mouth opening.

The close association of neurofibromatosis type 1 (NF1) with gliomas raises the question of whether the NF1 gene may be involved in the pathogenesis of sporadic astrocytic brain tumors. However, no frequent mutations within NF1 have been described in these tumors. Recent data on a limited series of gliomas indicate that NF1 expression may even be increased, thereby questioning the role of NF1 as a tumor suppressor in astrocytomas. In the present study, we examined the expression of NF1 in a series of 96 tumors including astrocytomas, meningiomas and plexiform neurofibromas. NF1 RNA transcription levels were compared to those of the reference genes B2M, ACTB and GAPD. The expression of OMGP, which is interposed in the NF1 gene, served as an additional control. NF1 expression did not significantly diverge among different malignancy stages of astrocytomas. As expected, the plexiform neurofibromas showed only very low NF1 expression. A striking finding was the highly variable expression of those genes selected to serve as references. While B2M and ACTB exhibited comparable levels of expression within different grades of astrocytomas and meningiomas, GAPD showed an inverse pattern in these tumors. In conclusion, NF1 expression is strongly reduced in NF1-associated plexiform neurofibromas but not in astrocytic tumors. The significant differences between B2M, ACTB and GAPD transcript levels brings into question the common practice of defining gene expression as a ratio between the transcripts of interest and those of these reference genes.

Neurofibromatosis type 1 (NF1) is an autosomal dominant cancer predisposition syndrome caused by a germline mutation in the NF1 gene. The loss of the second copy of NF1 within Schwann cell precursors (SCPs) contributes to the formation of plexiform neurofibromas (PNs) found in 30-50% of NF1 patients. PNs can progress into malignant peripheral sheath tumors (MPNSTs), an aggressive form of cancer and a leading cause of mortality in NF1 patients. Our lab previously demonstrated frequent chromosome 8 (Chr8) gain in NF1-MPNST patient-derived xenografts (PDX) and patient tumors. To investigate Chr8 gain’s role, we created isogenic NF1-/- iPSC cell lines with and without Chr8 gain. Trisomy 8 fibroblasts were obtained and single-cell cloned to establish wildtype (WT) and Chr8 gain populations. Washington University’s Genome Engineering &amp; Stem Cell Center (GESC@MGI) reprogrammed these cells into human induced pluripotent stem cells (hiPSCs). Using synthetic gRNA and CRISPR/Cas9, NF1 knockout lines were generated. Four iPSC cell lines were differentiated into SCPs, and cell survival and proliferation were assessed using Incucyte cell survival and CellTiter-Glo® Assay. Fluorescence in situ hybridization (FISH) and karyotyping validated the human iPSCs. qPCR revealed high expression of iPSC markers OCT3/4 and SOX2 in all iPSC lines. After differentiation, SCP markers (GAP43 and ITGA4) were upregulated in WT, NF1-/-, and Chr8 gain;NF1-/- SCP lines, demonstrating successful differentiation. Furthermore, Chr8 gain; NF1-/- SCPs displayed enhanced proliferation and increased cell survival compared to WT and NF1-/- SCPs, suggesting improved characteristics in the presence of Chr8 gain. In summary, our research provides insights into Chr8 gain and NF1 loss effects on SCP differentiation, proliferation, and survival. Understanding these molecular mechanisms may contribute to developing targeted therapies for NF1.

The April 2002 Case of the Month (COM). 35-year-old healthy man developed a mass in the right parotid gland. A superifical parotidectomy was performed for a 4.5 x 1.5 x 1.5 cm mass involving the intraparotid facial nerve. Grossly the tumor was multinodular, smooth and yellow with normal surrounding salivary gland. Microscopically, the tumor showed expanding nodules composed of proliferating fibroblasts, Schwann cells, and perineural-like cells in a myxoid stroma. Normal peripheral nerve twigs were identified in the periphery of the tumor. There was no increased mitotic activity, cellularity or nuclear pleomorphism. S-100 immunohistochemical stain was positive. The tumor was diagnosed as a solitary plexiform neurofibroma. Plexiform neurofibromas in this area have been described in children with von Recklinghausen's disease or neurofibromatosis 1 (NF 1). Plexiform neurofibromas typically involve deep seated nerve trunks and is considered pathognomonic for NF 1. This unusual case represents a solitary variant of plexiform neurofibroma presenting as a parotid mass in an adult patient without a personal stigmata or family history of NF 1.