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PubMed2004

Multiple intraorbital neurofibromas: a rare cause of proptosis.

BACKGROUND: Orbital neurofibromas are rare, accounting for 0.5 to 2.4 % of all orbital tumors. Generally, they manifest as slowly progressive proptosis, in a young adult or middle-aged person, and are usually solitary lesions. Sometimes, they can be associated with type 1 neurofibromatosis. We present a case of proptosis related to multiple intraorbital neurofibromas in an 82-year-old woman without type 1 neurofibromatosis. HISTORY AND SIGNS: An 82-year-old woman was referred for slowly progressive left proptosis associated with an ocular burning sensation. Neuro-ophthalmic examination revealed 9.5 mm of left exophthalmos, signs of minimal left optic neuropathy but normal extraocular movements. Magnetic resonance imaging revealed the presence of 4 intraorbital lesions. THERAPY AND OUTCOME: The two most anterior tumors were removed. Pathological studies showed these tumors to be neurofibromas. Post-operative evolution was favorable with reduction of left proptosis to 7 mm and disappearance of the burning sensation of the left eye. No other signs of neurofibromatosis were found. CONCLUSIONS: Multiple circumscribed intraorbital tumors are rare. Slowly progressive proptosis with radiological imaging of multiple round lesions should evoke the diagnosis of orbital neurofibromas, even in patients outside the typical age range or without neurofibromatosis.

Aged↗

PubMed1992

Growth and collagen synthesis of cultured neurofibroma fibroblasts.

Cells from cutaneous neurofibromas of three patients with von Recklinghausen's disease and skin fibroblasts from four healthy adults were cultured. After two passages, DNA and collagen syntheses were determined by measuring incorporation of [3H] thymidine and [3H] proline respectively, and expressed as the values per unit DNA content. These values from neurofibroma cells were increased by 54% in DNA synthesis and 60% (p < 0.05) in nondialyzable hydroxyproline synthesis, suggesting that neurofibroma cells in culture even after several passages still possess those characteristics corresponding to their pathological features in vivo. Collagen synthesized by neurofibroma cells appears to be normal as judged by intracellular degradation rates and SDS-polyacrylamide gel electrophoresis.

Adolescent↗

PubMed1997

Regional eruptive neurofibromas.

A 71-year-old woman presented with multiple, flesh-colored, papular lesions on the left dorsal side of the hand which had erupted 5 years earlier. No cafè-au-lait spots, freckles, or Lisch nodules were detected. Family history did not disclose neurofibromas or abnormal pigmentation. Two biopsy specimens of the lesions showed circumscribed, non-encapsulated neurofibromas. Segmental neurofibromatosis is characterized by the unilateral, segmental appearance of neurofibromas and/or cafè-au-lait spots in the absence of genetic transmission. The authors discuss the significance of localized multiple cutaneous neurofibromas in the absence of family history and suggest the possibility of a cutaneous hamartoma.

Aged↗

PubMed1990

Neuropeptides in cutaneous neurofibromas of von Recklinghausen's disease.

The occurrence of neuropeptides was studied in neurofibromas of von Recklinghausen's disease by indirect immunofluorescence. All non-plexiform cutaneous neurofibromas contained abundant vasoactive intestinal polypeptide, peptide histidine-isoleucine and calcitonin gene-related peptide immunoreactive nerves. The nerves were small and unmyelinated. Neuropeptides might be responsible for itch that occurs especially in small cutaneous neurofibromas. Neuropeptides are also suggested to act as modulators and/or trophic factors for neurofibroma growth.

Calcitonin Gene-Related Peptide↗

PubMed2006

Vitamin D deficiency associated with number of neurofibromas in neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25-hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, and correlated the findings in the patients with NF1 with their estimated number of dermal neurofibromas. Geometric mean (SD) serum 25-hydroxyvitamin D concentration was 14.0 (1.6) ng/mL among the patients with NF1 compared with 31.4 (1.7) ng/mL among healthy controls (p<<0.0001). The serum vitamin D concentration and number of dermal neurofibromas reported by patients with NF1 were inversely correlated (Spearman's rho = -0.572, p<0.00001). The occurrence of low serum vitamin D concentrations in people with NF1, especially those with many dermal neurofibromas, may provide new pathogenic insights and have important therapeutic implications.

Adult↗

PubMed2000

Expressions of various growth factors and their receptors in tissues from neurofibroma.

BACKGROUND: Platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta are known to enhance the growth of neurofibroma-derived cells from neurofibromatosis type 1 (NF-1) patients. OBJECTIVE: This study aims to elucidate whether these growth factors and their receptors are up-regulated in NF-1 patients. METHODS: Tissues and culture cells from neurofibroma in NF-1 patients, nontumor lesions in NF-1 patients, and the skin of normal controls were collected. To evaluate the expressions of growth factors and their receptors, reverse-transcriptase polymerase chain reaction and immunohistochemistry were performed. RESULTS: PDGF-beta receptor subunit was expressed in the neurofibroma tissues from NF-1 patients, but not in the nontumorous tissues from NF-1 patients or skin from normal controls. As for the other factors, there were no significant differences among these tissues. Neurofibroma sections also stained positive for the PDGF-beta receptor subunit. CONCLUSIONS: The interaction of PDGF and PDGF-beta receptor subunit may be important in the tumorigenesis of NF-1.

Becaplermin↗

PubMed1981

Neurotransmitter analysis of dermal neurofibromas: implications for the pathogenesis and treatment of neurofibromatosis.

We examined 15 dermal neurofibromas from five adults with disseminated neurofibromatosis. All tumors contained axons that reacted for catecholamines and tyrosine hydroxylase on histochemical stains. Assay of tissue homogenates identified norepinephrine as the catecholamine. Assays for dopamine and choline acetyltransferase were negative. Some axonal components of dermal neurofibromas may originate in sympathetic adrenergic neurons. Most dermal neurofibromas do not contain neuronal cell bodies, and some of the axons may maintain functional connections with proximal sympathetic neuronal cell bodies. Sympathetic denervation may therefore affect the growth of these dermal neurofibromas.

Adult↗

PubMed1993

Cosmetic possibilities and problems in eyelid neurofibromas.

Neurofibromatosis type 1 (NF1) is an inherited systemic disease with frequent ocular involvement. A typical alteration observed in NF1 is the eyelid plexiform neurofibroma, often associated with facial homolateral hypertrophy. In such cases, surgical cosmetic results are rather unsatisfactory, since plexiform neurofibromas classically show a non-capsulated mass, with a marked tendency to local recurrence. The techniques for a cosmetic attempt are discussed on the basis of a personal series of eyelid reconstructions in NF1. The results can be considered satisfactory in some cases, when the orbital shape is preserved and the eyelid structure has not been excessively altered by the neurofibroma; in all other cases, the cosmetic outcome is inferior to the patient's and parents' expectations. The serious problem of recurrence is however a limitation to cosmetic surgery in eyelid neurofibromas.

Child↗

PubMed1988

Avoidable complications of resection of major nerve trunk neurofibromas and schwannomas.

Neurofibromas and schwannomas of major nerve trunks may present with a variety of symptoms and other clinical concerns. These include: (1) the question of malignancy, (2) pain and paresthesias, (3) cosmesis, and (4) symptoms and impending problems related to compression of adjacent structures. For these reasons, patients with neurofibromas and schwannomas may have valid reasons for surgery. Precise delineation of the anatomical relationships of the lesions and their location within peripheral nerve trunks is essential for decision making regarding when and how they should be excised; judgement regarding risks vs. benefits must be made carefully. Microsurgical dissection can be utilized to remove some nerve trunk lesions with preservation of most or all motor and sensory functions. An important goal in resecting benign lesions is to avoid sacrificing major motor and sensory functions. Three cases are presented to illustrate these concepts: 2 cases with significant motor loss following partial resection of large neurofibromas involving peripheral nerve trunks and 1 case with a large femoral nerve neurofibroma excised from the nerve trunk with microsurgical dissection, leading to relief of symptoms and complete preservation of motor function.

Adult↗

PubMed1996

[Laser surgical treatment of neurofibromas].

In the past six years 24 patients with NF I were treated by laser-surgical technique. By applying whole-body therapy, all neurofibromas on the skin surface and in the subcutis were removed. With the passage of time our method of laser-surgical LPPL technique has become more sophisticated in order to achieve radical removal of all neurofibromas on the surface of the body. Our follow-up examinations have shown there to be no recurrence of neurofibromas eradicated by laser-surgical treatment provided they are removed completely and radically. In extreme of NF, our therapy is based in part on conventional surgical. Altogether the removal of all neurofibromas, including the smallest sizes, cannot be accomplished without laser-surgical technique. Now, the technique described represent the sole successful remedy of patients suffering from NF I.

Follow-Up Studies↗

PubMed2006

Orbital neurofibroma presenting with a negative Hounsfield unit on computerized tomography.

PURPOSE: To report a case of diffuse orbital neurofibroma which displayed an unusual computed tomography (CT) feature. METHODS: Results of ocular examination, orbital CT examination and pathological findings in a patient with a space-occupying orbital lesion are presented. RESULTS: Orbital CT evaluation of a male patient, aged one and a half years old, revealed a right orbital lesion with a strongly negative value in Hounsfield units. The preoperative diagnosis was a dermoid cyst. An anterior orbitotomy was performed, and the surgical specimen demonstrated a typical plexiform neurofibroma with routine hematoxylin and eosin staining and immunohistochemical studies. CONCLUSIONS: Plexiform orbital neurofibromas may demonstrate a negative Hounsfield value on CT examination.

Dermoid Cyst↗

PubMed1986

Multiple pulmonary neurofibromas with hypoxemia. Occurrence due to pulmonary arteriovenous shunts within the tumors.

A 62-year-old woman with multiple neurofibromas of the lung was found to have severe hypoxemia due to right-to-left shunting within the tumors. Pulmonary angiograms demonstrated that the major area of shunting was in a large tumor mass in the right lower lobe. Pathologically the neurofibromas were vascular with hyperplastic small arteries and arterioles and large dilated veins. Multiple pulmonary neurofibromas are rare; and, to our knowledge, never previously reported in association with pulmonary arteriovenous shunting.

Female↗

PubMed1999

Loss of NF1 allele in Schwann cells but not in fibroblasts derived from an NF1-associated neurofibroma.

Neurofibromas, the hallmark of neurofibromatosis 1, are composed mainly of Schwann cells and fibroblasts. Inactivation of both NF1 alleles is the cause of these benign tumors, but it is unknown which cell type is the progenitor. In this study, we selectively cultured Schwann cells from an NF1-associated neurofibroma. Fibroblasts were also obtained by culturing the tumor cells under standard conditions. Using four intragenic markers, we genotyped the NF1 locus in the original tumor and in the derived Schwann cells and fibroblasts. Loss of heterozygosity for two informative markers, which indicates loss of one NF1 allele, was found in Schwann cells but not in fibroblasts. This result suggests that genetic alterations of the NF1 gene in Schwann cells are responsible for the development of neurofibromas.

Alleles↗

PubMed1982

Nonepithelial tumors of the nasal cavity, paranasal sinuses and nasopharynx. A clinicopathologic study. XII: Schwann cell tumors (neurilemoma, neurofibroma, malignant schwannoma).

Twelve Schwann cell tumors (two neurilemomas, six neurofibromas, and four malignant schwannomas), arising in the nasal cavity, paranasal sinuses or nasopharynx, are described. Schwann cell neoplasms only rarely develop in this area. Clinically, these tumors lead to nonspecific symptoms including nasal obstruction epistaxis, facial pain and swellling, and proptosis, similar to those produced by other neoplasms that involve this area. On radiologic examination, a mass lesion may be identified. Benign Schwann cell tumors may lead to bone erosion, which thus is not necessarily a sign of malignancy. The correct diagnosis of Schwann cell tumor is usually made only when histologic sections are studied. The histologic differentiation between Schwann cell neoplasms and myxomas, fibroblastic tumors, fibrous histiocytomas and fibro-osseous lesions is discussed. Treatment depends upon the type of tumor. Neurilemomas, which usually are encapsulated neoplasms, can be treated by local excision. Neurofibromas may infiltrate extensively, and thus may require an extensive surgical resection; however, functional and cosmetic considerations should be taken into account because neurofibromas, even if incompletely excised, may recur clinically only after many years. Malignant schwannomas tend to be aggressive neoplasms, but because of the anatomy of the area, radical resections leading to complete removal of the tumor cannot always be carried out.

Adult↗

PubMed2005

Subcutaneous neurofibromas are associated with mortality in neurofibromatosis 1: a cohort study of 703 patients.

Neurofibromatosis 1 (NF1) is a common genetic disorder with an autosomal dominant mode of inheritance, an increased morbidity and mortality, and a shorter lifespan. Although the disease is fully penetrant by the age of 8, the variability in symptoms and complications is high, even among members of the same family. The aim of this study was to identify easily recognizable clinical features that may be associated with mortality in a cohort of patients affected with NF1. We used prospectively collected data from the Neurofibromatosis Institute Database (NFID) and included in our analysis 703 patients who fulfilled the NIH diagnostic criteria for NF1. Clinical, especially dermatological features were tested as potential factors associated with mortality. Among the patients, 405 (57.6%) were children and 298 (42.4%) were adults. The mean follow-up was 2.4 years (median = 0.98, range: 0-15.3 years). Forty patients died during follow-up, mostly due to tumor development such as sarcoma (n = 18). In the adult population, subcutaneous neurofibromas (odds ratio [OR] = 3.6, 95% confidence interval (CI): [1.2-11.3], P = 0.02) and male gender (OR = 5.6, [1.5-20.9], P = 0.004) were independent predictors of mortality after adjustment for age. Among children, the presence of facial plexiform neurofibromas and pruritus were significantly associated with mortality in univariate analysis. Our study describes independent risk factors of mortality in a large cohort of adult and pediatric patients. Close follow-up should be obtained for patients presenting with subcutaneous neurofibromas.

Adolescent↗

PubMed2005

Metastatic acinic cell carcinoma in a neurofibroma mistaken for carcinosarcoma.

BACKGROUND: Tumor-to-tumor metastasis is a rare, but well-recognized, entity most commonly involving metastatic carcinoma to a mesenchymal neoplasm. We report a case of acinic cell carcinoma of the parotid gland metastatic to a neurofibroma. METHODS AND RESULTS: A 55-year-old man with a history of a high-grade acinic cell carcinoma of the parotid was seen with a mass at the surgical site and metastatic foci in the scalp 10 months postoperatively. The resection specimen revealed a spindle cell lesion with metastatic foci of high-grade adenocarcinoma, initially diagnosed as a carcinosarcoma. The bland morphology and S-100-positive expression of the spindle cell lesion confirmed the diagnosis of neurofibroma. The high-grade features of the carcinomatous foci and their similarity to the primary tumor confirmed the presence of a tumor-to-tumor metastasis. CONCLUSION: To our knowledge, this is the first reported case of acinic cell carcinoma metastatic to a neurofibroma, an important entity in the differential diagnosis of biphasic tumors of the head and neck.

Carcinoma, Acinar Cell↗

PubMed2006

Comprehensive NF1 screening on cultured Schwann cells from neurofibromas.

Neurofibromatosis type 1 (NF1) is mainly characterized by the occurrence of benign peripheral nerve sheath tumors or neurofibromas. Thorough investigation of the somatic mutation spectrum has thus far been hampered by the large size of the NF1 gene and the considerable proportion of NF1 heterozygous cells within the tumors. We developed an improved somatic mutation detection strategy on cultured Schwann cells derived from neurofibromas and investigated 38 tumors from nine NF1 patients. Twenty-nine somatic NF1 lesions were detected which represents the highest NF1 somatic mutation detection rate described so far (76%). Furthermore, our data strongly suggest that the acquired second hit underlies reduced NF1 expression in Schwann cell cultures. Together, these data clearly illustrate that two inactivating NF1 mutations, in a subpopulation of the Schwann cells, are required for neurofibroma formation in NF1 tumorigenesis. The observed somatic mutation spectrum shows that intragenic NF1 mutations (26/29) are most prevalent, particularly frameshift mutations (12/29, 41%). We hypothesize that this mutation signature might reflect slightly reduced DNA repair efficiency as a trigger for NF1 somatic inactivation preceding tumorigenesis. Joint analysis of the current and previously published NF1 mutation data revealed a significant difference in the somatic mutation spectrum in patients with a NF1 microdeletion vs. non-microdeletion patients with respect to the prevalence of loss of heterozygosity events (0/15 vs. 41/81). Differences in somatic inactivation mechanism might therefore exist between NF1 microdeletion patients and the general NF1 population.

Adaptor Proteins, Signal Transducing↗

PubMed1994

The growth regulation of neurofibroma cells in neurofibromatosis type-1: increased responses to PDGF-BB and TGF-beta 1.

In neurofibromatosis type-1 (NF-1), abnormal growth regulation may be related to the formation of multiple neurofibromas. We investigated the growth responses of neurofibroma-derived cells (NF cells) and control skin fibroblasts to various growth factors. The responses to platelet-derived growth factor (PDGF-BB) and transforming growth factor-beta 1 (TGF-beta 1) in NF cells were significantly greater than those in control fibroblasts. The increased response to PDGF-BB in NF cells was accompanied by an increased number of PDGF beta receptors, which was demonstrated by both 125I PDGF-BB binding assay and immunoblotting analysis. The increased response to TGF-beta 1 was assumed to be mediated through PDGF-like protein induction; TGF-beta 1-treated NF cells produced greater amounts of 36-kD PDGF-like protein than TGF-beta 1-treated control fibroblasts. These observations suggest that certain growth factors, e.g., PDGF-BB and TGF-beta, may play some role in the development of neurofibromas in NF-1.

Becaplermin↗