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PubMed2003

A corneal diffuse neurofibroma as a manifestation of von recklinghausen disease.

PURPOSE: To report a case of a primary corneal diffuse neurofibroma in a patient with von Recklinghausen disease (NF-1). METHODS: Case report. A physical examination and histopathology were performed. The immunohistochemical studies were performed using an avidin-biotin-peroxidase complex technique on formalin-fixed and paraffin-embedded tissue. Histologic sections from corneal tissue were incubated with primary antibodies against vimentin and S-100 protein. A complementary ultrastructural study of the same formalin-fixed and paraffin-embedded tissue was made. RESULTS: The ophthalmologic examination revealed a yellowish-white elevated mass that involved the supratemporal cornea but not the limbus. Histologic study showed a tumor of the peripheral nerve sheath, a diffuse neurofibroma in the corneal stroma, and proliferation of spindle cells with markedly elongated nuclei. Cells comprising the tumor reacted with vimentin and S-100 protein, and the ultrastructural studies revealed myelinated nerve fibers confirming the diagnosis. CONCLUSION: The development of a primary diffuse neurofibroma in the cornea of patients with von Recklinghausen disease is possible. The present case supports the statement that neurofibromas arising from the peripheral nerve sheath may involve any part of the body.

Cornea↗
PubMed2003

Intraparotid facial nerve neurofibromas.

OBJECTIVES: To provide an awareness of intraparotid facial nerve neurofibroma as a cause of parotid masses and to describe their characteristics and management considerations. STUDY DESIGN: Case report with literature review. METHODS: The medical records of three patients with intraparotid facial nerve neurofibromas are reviewed, and data concerning the patient's presentations, treatment, and disease course are presented with a review of the world's literature on intraparotid facial nerve neurofibromas. CONCLUSIONS: Tumors arising from the extratemporal course of the facial nerve are quite rare. The tumors arise from Schwann cells and include the schwannoma and the neurofibroma. The overwhelming benign nature of these lesions necessitates a conservative course of treatment. Histological diagnosis should be followed by a limited tumor excision with emphasis on retaining normal facial nerve function. Malignant lesions require wide excision with facial nerve grafting or facial nerve reanimation.

Adult↗
PubMed1994

Merkel cells in neurofibromas and neurilemomas.

Merkel cells are an integral component of the cutaneous nervous system. They are commonly associated with dermal nerves under normal physiological conditions. We postulated that Merkel cells may be present in increased numbers within the epidermis overlying benign peripheral nerve sheath tumours such as neurilemomas and neurofibromas. Paraffin-embedded skin biopsy specimens from 21 patients with neurilemomas and 26 with neurofibromas, were analysed for the presence of Merkel cells using a standard immunohistochemical assay (avidin-biotin-peroxidase complex system) with an antibody to cytokeratin 8 (CAM 5.2). Ten cases of leiomyomas were examined as controls. Merkel cells were identified in the interfollicular area of the basal cell layer overlying 14 of 21 (67%) neurilemomas and nine of 26 (35%) neurofibromas. Merkel cells were more frequently observed in increased numbers in a linear array within the basal cell layer in neurilemomas than in neurofibromas, where they were found as individual cells. No Merkel cells were found in the epidermis overlying leiomyomas. The results of this study suggest that Merkel cells are quantitatively increased in the basal cell layer of the epidermis overlying benign peripheral nerve sheath tumours, particularly neurilemomas.

Humans↗
PubMed1993

Mast cell numbers in melanocytic naevi and cutaneous neurofibromas.

This study aimed to determine the diagnostic utility of mast cell densities in distinguishing neurotised ("neural") melanocytic naevi from neurofibromas. Three groups of lesions were studied: neurofibromas, neural naevi, and naevi showing no neural change (control naevi). A Giemsa stain was used to demonstrate mast cells. The median mast cell density in the neurotised naevus group was significantly higher (p < 0.005) than that of both the neurofibroma and control naevus groups, but the distributions of the individual density counts overlapped considerably. The sensitivity and specificity of the mast cell density as a potential discriminator between neurotised naevi and neurofibromas, determined in relation to the optimal discrimination value obtained using Bayes' minimum cost decision rule, were low. It is concluded that mast cell density on its own is of little use as a classification tool but could be of value in the context of a multivariate decision rule.

Adolescent↗
PubMed2004

Solitary neurofibroma of the spermatic cord.

Neurofibromas, which arise from perineural and Schwann cells, commonly occur throughout the body, but they rarely have been reported to originate from the spermatic cord. The solitary neurofibroma is a localized tumour that, by definition, occurs in patients who do not have von Recklinghausen's disease. Its exact incidence is unknown because of the difficulty in excluding von Recklinghausen's disease in some cases. Leiomyomas, lipomas, fibromas, haemangiomas, and epidermoid cysts have been described as benign tumours of the scrotum, but rarely has an extratesticular solitary neurofibroma of the spermatic cord been reported. We report a case of a solitary neurofibroma arising from the left spermatic cord. No signs of von Recklinghausen's disease were identified.

Aged↗
PubMed2002

Therapy for plexiform neurofibromas in children with neurofibromatosis 1: an overview.

Plexiform neurofibromas are one of the most common and disabling features of neurofibromatosis 1. Treatment options for patients with plexiform neurofibromas have been limited, with surgery being the primary option for patients with progressive lesions causing significant morbidity. Trials have evaluated other treatment approaches, including the use of antihistamines, maturation agents, and antiangiogenic agents. The design of such trials and entry criteria have been quite variable, and results have been difficult to interpret. As more is understood concerning the molecular genetic underpinnings of plexiform neurofibromas, new avenues of treatment are being explored. Evaluation of clinical trials is challenging because of the unpredictable nature of plexiform neurofibromas and difficulties in measuring objective responses. The use of innovative neuroimaging techniques and other outcome measures may greatly improve the design of trials and evaluation of potential effective agents.

Child↗
PubMed2006

Molecular, genetic, and cellular pathogenesis of neurofibromas and surgical implications.

Neurofibromatosis 1 (NF1) is a common autosomal dominant disease characterized by complex and multicellular neurofibroma tumors. Significant advances have been made in the research of the cellular, genetic, and molecular biology of NF1. The NF1 gene was identified by positional cloning. The functions of its protein product, neurofibromin, in RAS signaling and in other signal transduction pathways are being elucidated, and the important roles of loss of heterozygosity and haploinsufficiency in tumorigenesis are better understood. The Schwann cell was discovered to be the cell of origin for neurofibromas, but understanding of a more complicated interplay of multiple cell types in tumorigenesis, specifically recruited heterogeneous cell types such as mast cells and fibroblasts, has important implications for surgical therapy of these tumors. This review summarizes the most recent NF1 and neurofibroma literature describing the pathogenesis and treatment of nerve sheath tumors. Understanding the biological underpinnings of tumorigenesis in NF1 has implications for future surgical and medical management of neurofibromas.

Animals↗
PubMed2006

Superficial femoral vein invasion by a benign neurofibroma in a non-neurofibromatosis patient: case report.

OBJECTIVE AND IMPORTANCE: Neurofibromas are benign neural sheath tumors arising from intraneural supporting cells. Such tumors are characteristic of neurofibromatosis Type I (von Recklinghausen disease) but also occur sporadically. Vascular involvement by neurofibromata is rare, but has been described in the past in the context of neurofibromatosis. There is, to our knowledge, no description of vascular involvement by a neurofibroma in a non-neurofibromatosis patient. CLINICAL PRESENTATION: A 40-year-old woman presented with a 4 year history of a right thigh mass associated with diffuse lower extremity pain. She had no other clinical manifestations of neurofibromatosis and no known family member with neurofibromatosis Type I. Magnetic resonance imaging scans revealed a well-defined solid mass in the anteromedial aspect of the right thigh closely associated with the superficial femoral vein. INTERVENTION: The vessel segment and encapsulated mass were resected "en bloc" after proximal and distal ligation of the vein. The pathological appearance of the mass was consistent with a benign neurofibroma that had infiltrated all layers of the vessel. CONCLUSION: Vessel invasion by a benign sporadic neurofibroma is a rare occurrence with potentially severe implications for the patient. It suggests that surgical removal of asymptomatic benign-appearing lesions of that type should be considered if they are adjacent to important anatomical structures.

Adult↗
PubMed2001

Solitary neurofibroma of the nasal cavity: resection with endoscopic surgery.

We present a case of neurofibroma of the nasal cavity treated by endoscopic surgery. A 71-year-old female had complained of left-sided nasal obstruction for the past four years. Anterior rhinoscopy, computed tomography (CT) and magnetic resonance imaging (MRI) revealed a tumour involving the left nasal cavity. Histological and immunohistochemical examination showed the tumour to be a neurofibroma. The tumour was resected with endoscopic surgery. Neurofibroma arising in the area of the nose and paranasal sinuses is rare. We discuss the clinical and pathological characters of neurofibroma arising in the nasal cavity.

Aged↗
PubMed2006

Perinatal epidermal growth factor receptor blockade prevents peripheral nerve disruption in a mouse model reminiscent of benign world health organization grade I neurofibroma.

Benign peripheral nerve tumors called neurofibromas are a major source of morbidity for patients with neurofibromatosis type 1. Some neurofibroma Schwann cells aberrantly express the epidermal growth factor receptor (EGFR). In a mouse model in which the CNPase promoter drives expression of human EGFR in Schwann cells, nerves develop hypertrophy, mast cell accumulation, collagen deposition, disruption of axon-glial interactions, characteristics of neurofibroma and are hypoalgesic. Administration of the EGFR antagonist cetuximab (IMC-C225) for 2 weeks beginning at birth in CNPase-hEGFR mice normalized all pathologies at 3 months of age as evaluated by hotplate testing or histology and by electron microscopy. Mast cell chemoattractants brain-derived neurotrophic factor, monocyte chemoattractant protein-1, and transforming growth factor-beta1, which may account for mast cell accumulation and fibrosis, were reduced by cetuximab. Later treatment was much less effective. A birth to 2-week pulse of cetuximab blocked hEGFR phosphorylation and Schwann cell prolifera-tion in perinatal mutant nerve, so CNPase-hEGFR Schwann cell numbers correlate with the cetuximab effect. A >250-fold enlarged population of EGFR(+)/p75(+) cells was detected in newborn Nf1(+/-) mouse nerves. These results suggest the existence of an EGFR(+) cell enriched in the perinatal period capable of driving complex changes characteristic of neurofibroma formation.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1990

Cellular peripheral neural tumors (neurofibromas) in children and adolescents: a clinicopathological and immunohistochemical study.

Nine examples of a cellular peripheral neural tumor (CPNT) were identified in a review of 139 peripheral nerve sheath neoplasms in children, which included 60 neurofibromas and 16 malignant peripheral nerve sheath tumors. The mean age at diagnosis of these nine patients was 7 years, with six presenting in the first decade of life and four were noted at birth. The male:female ratio was 0.5. Topographically, the tumors were located in the extremities, 4; head and neck, 3; and trunk, 2. One or another stigmata of von Recklinghausen's neurofibromatosis (VRN) was present in four patients. After initial resection, seven children remained well, but two developed a recurrence; the histology was identical to the original tumor in one case but overt malignant transformation had occurred in the second. This case was the only tumor-related death in this series. The CPNT was a circumscribed but nonencapsulated mass measuring 1.8-7.5 cm in greatest dimension in the subcutaneous and deep soft tissues and had a compact spindle cell pattern, occasional mitoses, and minor foci of typical neurofibroma. Immunohistochemical staining revealed vimentin expression in all seven cases, Leu-7 in six, myelin basic protein and S-100 protein in five, desmin in one, and actin in none. In contrast to neurofibroma and malignant peripheral nerve sheath tumors, CPNT tended to occur earlier, either congenitally or in the first decade, and slightly more commonly in females. The anatomical distribution and pattern of immunoreactivity were similar to neurofibroma. However, the cellularity and mitotic activity of these neoplasms were sufficiently disquieting as to raise concerns about the prognosis, and in one case, the tumor behaved in an unequivocally malignant fashion. When a peripheral neural tumor with the pathologic features described in this study is encountered, wide excision and careful clinical follow-up are recommended.

Actins↗
PubMed2005

Solitary colonic neurofibroma in a patient with transient segmental colitis: case report.

Neurofibromas of the large bowel are very rare and usually are part of the colonic involvement in neurofibromatosis type 1 (Nf1, von Recklinghausen's disease). Solitary neurofibromas of the colon are extremely rare. We describe a case of an isolated neurofibroma that was found in the large bowel of a patient who suffered from segmental colitis and presented with bloody diarrhea. A review of the literature is also included, concerning the disclosure of isolated neurofibromas in the gut and other body parts and the type of gastrointestinal involvement in von Recklinghausen's disease.

Aged↗
PubMedDate not supplied

Solitary intraosseous neurofibroma of mandible.

Solitary intraosseous neurofibroma is a rare benign non-odontogenic tumor. Although neurofibromas occur predominantly as a feature of neurofibromatosis affecting the soft tissue, a few cases of solitary intraosseous neurofibromas of the jaw have been reported. We herewith report a case of solitary intraosseous neurofibroma of mandible in a middle-aged woman with a discussion on its clinical, radiological, and histopathological presentation along with review of cases.

Adult↗
PubMed1999

Neurofibroma of the urinary bladder.

BACKGROUND: Neurofibroma of the urinary bladder is rare. Only isolated case reports have appeared. Information regarding the long term follow-up of patients with neurofibroma is limited. METHODS: The authors studied 4 cases of neurofibroma of the bladder diagnosed at Mayo Clinic from 1965 through 1990. Immunostains for S-100 protein, neurofilament protein, epithelial membrane antigen (EMA), cytokeratin (CAM 5.2; AE 1/3), Type IV collagen, MIB-1, and p53 protein were performed in all cases, as was Alcian blue at pH 2.5. The mean follow-up was 9.6 years (range, 2-18 years). RESULTS: The mean age at diagnosis was 17 years (range, 7-28 years); the male-to-female ratio was 1:1. All four patients exhibited physical stigmata of neurofibromatosis type 1. Clinical presentations included hematuria (one patient), irritative symptoms (two patients), and pelvic mass (one patient). Long term urinary complications included bladder atony (two patients), neurogenic bladder (one patient), and recurrent urinary tract infection with hematuria (one patient). Subsequently, two patients underwent partial cystectomy and one a complete cystectomy. Involvement of the bladder was generalized in all four cases. Three tumors were transmural, showing a diffuse and plexiform pattern of growth; in the fourth case, a superficial biopsy showed only diffuse submucosal growth with conspicuous pseudo-Meissnerian corpuscle formation. An Alcian blue positive, variably collagenized matrix was present in all cases. Tumor cells displayed immunoreactivity for S-100 protein and Type IV collagen in all cases. Neurofilament protein positive axons were evident in three cases; all other immunostains were negative. The mean MIB-1 labeling index was 3.2% (range, 0.9-7.3%). No malignant transformation was observed during a mean follow-up of 9.6 years. CONCLUSIONS: Neurofibroma of the bladder presents early in life, is of the plexiform type with a diffuse component, and usually occurs in the setting of generalized neurofibromatosis type 1 rather than as isolated visceral neurofibromatosis. Malignant transformation did not occur in any of these 4 patients during a mean follow-up time of 9.6 years.

Adolescent↗
PubMed1990

Type VI collagen. In situ hybridizations and immunohistochemistry reveal abundant mRNA and protein levels in human neurofibroma, schwannoma and normal peripheral nerve tissues.

Cutaneous neurofibromas contain an extensive extracellular matrix composed of collagenous and non-collagenous macromolecules. In this study, the expression of type VI collagen genes in cutaneous neurofibromas was examined by a combination of in situ hybridizations and immunohistochemistry. In situ hybridizations with a 32P-labeled human type VI collagen-specific cDNA revealed that the majority of cells within neurofibromas expressed the gene for alpha 2(VI) collagen chain. The number of cells expressing clearly detectable levels of alpha 2(VI) collagen mRNA was considerably higher than that of cells actively expressing the pro alpha 1(I) or pro alpha 1(III) collagen genes. The presence of type VI collagen epitopes within the neurofibromas was also demonstrated by immunostaining with specific polyclonal antibodies. The expression of type VI collagen genes in neural tissues was further examined by immunostaining of a benign schwannoma tissue specimen consisting of Schwann cells. The results indicated close association of type VI collagen epitopes with the neoplastic Schwann cells. Immunolocalization of type VI collagen epitopes within normal human peripheral nerve revealed pericellular staining of perineurial cells and Schwann cells, suggesting synthesis of type VI collagen by these cell types. These results suggest that the expression of type VI collagen gene is active in nerve-derived tissues, and that type VI collagen may be a major component of the extracellular matrix in neural connective tissues.

Collagen↗
PubMed1993

A controlled multiphase trial of ketotifen to minimize neurofibroma-associated pain and itching.

BACKGROUND AND DESIGN: Based on potential contributions of mast cells to neurofibroma-associated itching, pain, and tenderness, the mast cell blocker ketotifen fumarate (Zaditen, Sandoz Pharmaceuticals Corp, Hanover, NJ) has been proposed as a treatment for these symptoms. To test the hypothesis that ketotifen decreases neurofibroma-associated itching, pain, and tenderness, data were accumulated from two protocols. The first was an open-label protocol involving 25 patients with relatively severe symptoms (1170 patient-months), and the second was a double-blind protocol involving 27 patients with either relatively mild or severe neurofibroma-associated symptoms (316 patient-months). All subjects received either oral placebo or 2 to 4 mg of ketotifen fumarate per day. Using a scale of 1 to 10, symptoms were measured before, during, and after treatment. RESULTS: Itching severity scores (means) were as follows: for all patients receiving ketotifen, 7.8 before, 2.8 during, and 7.2 after treatment; for ketotifen-treated patients in the double-blind protocol, 6.6 before, 3.9 during, and 6.4 after treatment; and for placebo-treated patients, 6.0 before and 6.0 during treatment. Pain and tenderness severity scores (means) were as follows: for all patients treated with ketotifen, 7.6 before, 3.6 during, and 6.6 after treatment; for double-blind ketotifen-treated patients, 6.3 before, 4.6 during, and 6.1 after treatment; and for placebo-treated patients, 7.9 before and 6.7 during treatment. CONCLUSIONS: Pretreatment, treatment, and posttreatment levels of itching, pain, and tenderness associated with neurofibromas, using both open-label and double-blind protocols, indicate that ketotifen offers a realistic approach to treating these symptoms.

Adult↗
PubMed1998

[Neurofibroma of the parapharyngeal space: a case report].

Neurofibroma is rarely found arising in the head and neck region. Parapharyngeal space neurofibroma is one of the rare complications of neurofibromatosis type I, occurring in less than 5% of all parapharyngeal space neoplasms. Solitary neurofibroma type II in this location has not been reported so far in literature. In this paper we describe a case of a huge neurofibroma of parapharyngeal space, indicating the main diagnostic procedures (especially CT scan), and report the surgical treatment.

Female↗
PubMed1996

Localized hypertrichosis associated with periorbital neurofibroma: clinical findings and differential diagnosis.

BACKGROUND: Congenital localized hypertrichosis in the periorbital region is an uncommon finding. The authors report two patients with hypertrichosis and cutaneous hyperpigmentation overlying a periorbital neurofibroma. METHODS: In addition to a complete ophthalmic and systemic examination, the patients underwent computed tomography of the head and biopsy of the tumor. RESULTS: Case 1 previously had received a diagnosis of neurofibromatosis type I. On examination, hyperpigmentation, hypertrichosis, and swelling in the right supraorbital region were noted. A computed tomographic scan showed a tumor in the same region. The tumor was removed, and a plexiform neurofibroma was diagnosed. Case 2 was admitted with hyperpigmentation, hypertrichosis, and swelling of the left half of her face. Other signs of neurofibromatosis were absent. A computed tomographic scan showed a tumor, which was underlying the skin changes. Results of histologic examination of the biopsy specimen showed a plexiform neurofibroma. CONCLUSION: Neurofibroma-associated hypertrichosis should be considered in the differential diagnosis of congenital localized hypertrichosis.

Adolescent↗