Vacuolated cells in neurofibroma: an immunohistochemical study

BACKGROUND: Vacuolated cells could be encountered in neurofibroma. OBJECTIVES: Frequency and immunohistochemical feature of vacuolated cells in neurofibroma. METHODS: Sixty-two lesions of neurofibroma including five plexiform neurofibromas were re-evaluated for the search of vacuolated cells. Immunohistochemical analysis was performed for cases with vacuolated cells. RESULTS: In five cases of plexiform neurofibroma and four cases of sporadic neurofibroma with endoneurial component, presence of vacuolated cells in the endoneurial mucoid area was noted. They were immunoreactive both with S-100 protein and CD34, mostly negative for factor XIIIa and negative for epithelial membrane antigen. Vacuolated cells were found neither in the diffuse portion of plexiform neurofibroma nor in sporadic diffuse neurofibroma. CONCLUSION: Presence of vacuolated cells is a highly characteristic feature of endoneurial portion of neurofibroma. Considering immunoreactivity both with S-100 protein and CD34 in the majority of vacuolated cells, they could be regarded as to represent endoneurial precursor cells in a certain stage of differentiation to Schwann cells.     

A Case of Isolated Plexiform Neurofibroma in a Patient with Myasthenia Gravis

We report a case of an isolated plexiform neurofibroma occurring in a patient with myasthenia gravis. A 48-year-old man presented with asymptomatic skin-colored nodules on the tip of his 4th finger. Microscopically, a plexiform neurofibroma was identified located in the dermis that appeared to originate from small superficial nerves. He had a 20-year history of treated myasthenia gravis; otherwise, his personal and family histories were unremarkable. Given that myasthenia gravis is a disorder of the peripheral nerves, plexiform neurofibromas could be associated with myasthenia gravis. However, the development of an isolated plexiform neurofibroma in a case of myasthenia gravis has not yet been reported. The occurrence of a neurofibromas in a patient with myasthenia gravis suggests a link in the pathogenesis of these two diseases.     

Hair Whorl as an Indicator of a Mediastinal Plexiform Neurofibroma

Abstract: We report a boy with neurofibromatosis type 1 (NF-1) who had nonspecific respiratoi symptoms and a mediastinal mass. In addition to multiple cafe au lait macules and subcutaneous neurofibromas, he had a hair whorl over the spine at the level of a deep mediastinal mass demonstrated by CT scan and MR examination. Thoracoscopy and biopsy of the mass revealed a plexiform neurofibroma. The clinical sign of a hair whorl may assist the clinician in early recognition of a paraspinal plexiform neurofibroma.     

Hemorrhage into a plexiform neurofibroma induced by trauma: a rare complication of von Recklinghausen's disease

A case of hemorrhage into a plexiform neurofibroma of a 53-year-old woman is described. Immediately after trauma to the plexiform neurofibroma on her scalp, she noticed severe headaches and sudden enlargement of the tumor. The tumor continued to enlarge slowly. Her headaches also continued until tumor excision. The specimen taken during surgery surrounded a round cavity about 7 cm in diameter containing coagulated blood. Numerous, old, perivascular hemorrhages around many dilated vessels with extremely thin walls were revealed by histological examination.     

Pigmented plexiform neurofibroma: Distinction from a large congenital melanocytic nevus

The substantial clinical and histologic overlap between neurotized congenital melanocytic nevi and the subset of plexiform neurofibromas with hyperpigmentation and hypertrichosis of the overlying skin (pigmented neurofibroma) has led to considerable confusion in the literature. A dark-brown, hypertrichotic plaque covered much of the right lower aspect of the trunk of a 1-year-old girl with a diffuse and plexiform neurofibroma in the same area, numerous café-au-lait macules, and intertriginous freckling. The latter findings were diagnostic of neurofibromatosis-1, which was further supported by the presence of unidentified bright objects on magnetic resonance imaging of the brain. Histologic examination of the hyperpigmented plaque revealed melanocytic hyperplasia at the dermoepidermal junction and a proliferation of rounded, pigmented melanocytes dispersed individually and in occasional small nests in the papillary dermis and scattered within underlying neurofibromatous tissue. Immunohistochemical staining with A103 (Melan-A/MART-1) and PNL2 confirmed the melanocytic differentiation of the pigmented cells, whereas glial fibrillary acidic protein and Leu-7 were detected only within plexiform areas and slender neuroid spindle cells. This case draws attention to the pigmented neurofibroma as a distinct clinicopathologic entity resulting from proliferation of melanocytes and neurosustentacular cells in the setting of neurofibromatosis-1.     

Evaluation of plexiform neurofibroma in neurofibromatosis type 1 in 18 family members of 3 generations: ultrasonography and magnetic resonance imaging a diagnostic supplement

Plexiform neurofibroma in neurofibromatosis type 1, an autosomal-dominant genetic disorder, is characterized by a combination of interlacing components or a network. The prominent enlargement of a nerve with tumor nodules results in the gross pathologic appearance termed "bag of worms." Plexiform neurofibroma was found in two of seven family members with neurofibromatosis type 1 in three generations. Ultrasonography/color doppler and magnetic resonance imaging, in addition to microscopic pathology, were used as diagnostic tools, and their indications for future use in the diagnosis of plexiform neurofibroma are highlighted.     

Cutaneous Plexiform Schwannoma of the Finger Not Associated with Neurofibromatosis

Plexiform schwannoma is a rare, benign, peripheral nerve sheath tumor that occurs as an uncommon nodular variant of schwannoma. It is important to recognize this tumor because it can be misdiagnosed as plexiform neurofibroma. In contrast to the latter, however, plexiform schwannoma is not associated with neurofibromatosis (von Recklinghausen disease). We report a case of plexiform schwannoma located on the index finger of a 20-year-old male patient with no signs of neurofibromatosis.     

Solitary subungual neurofibroma in the right first finger

Background Neurofibromas may occur as part of neurofibromatosis or as a solitary tumor. Solitary subungual neurofibroma appears to be a rare condition. Up until now, less than 10 case reports of solitary subungual neurofibroma have been documented. Solitary subungual neurofibroma is difficult to diagnose, particularly as it is often small and without obvious symptoms. Awareness of the diagnosis is emphasized to prevent unnecessary delay in treatment. So, understanding the differentiation and diagnosis of solitary subungual neurofibroma has a great value. Methods A 32‐year‐old woman presented with a two‐year history of painless thickening and elevation of the nail plate of the right first finger. She was treated with complete surgical excision of the tumor, and we performed pathological examination of the biopsy specimen. Results The final diagnosis of the tumor was solitary neurofibroma. After surgery, the nail regrew with a good cosmetic result. After 10 months of follow‐up, there were no signs of recurrence of the tumor. Conclusion Solitary subungual neurofibroma appears to be a rare condition, and immunohistochemistry is the key to the diagnosis. Complete surgical excision should be considered as the curative treatment of choice for them.     

Large hairy pigmented spots in neurofibromatosis type 1: an atypical form of neurofibromas]

INTRODUCTION: Large hairy pigmented spots have been observed in patients with neurofibromatosis type 1. In this study we tried to determine the nature and the frequency of these hairy pigmented spots in neurofibromatosis type 1. PATIENTS AND METHODS: In patients with neurofibromatosis type 1, hairy pigmented spots with a diameter more than 3 cm were systematically notified. Realisation of the biopsy of the spot was proposed to the patient. RESULTS: Among 614 patients with neurofibromatosis type 1, seven (1.1 p. 100) had a large hairy pigmented spot. Biopsy was realized in six cases. In five cases, diagnosis was superficial and plexiform neurofibroma, the 6(th) case was a Becker's nevus. CONCLUSION: Large hairy pigmented spot is a rare aspect of superficial and plexiform neurofibroma during neurofibromatosis type 1. A biopsy may be useful if it is necessary for the disorder diagnosis.     

Intratumoral fat in neurofibroma

Three cases of a solitary neurofibroma showing focal fatty changes are reported. Fatty changes in a neurofibroma are rarely observed and have not been reported, and also, the pathogenesis of neurofibroma has not been clarified. We postulate that the fatty changes in a neurofibroma may be the result of so-called senescent change or chronic injury. The origin of adipose cells may be attributable to fatty infiltration from abutting tissues or to a metaplasia of tumor cells or resident fibroblasts.     

Histopathologically dysplastic neurofibromas in neurofibromatosis 1: diagnostic criteria, prevalence and clinical significance

BACKGROUND: Malignant peripheral nerve sheath tumours (MPNSTs) correspond to the most frequent and aggressive neoplasic complications associated with poor prognosis in neurofibromatosis 1. OBJECTIVES: To define the dysplastic neurofibroma potentially at risk of transformation and evaluate its prevalence and incidence. METHODS: According to our database, we retrospectively included, between 1 March 2000 and 31 August 2004, all patients who had subcutaneous and/or plexiform neurofibromas removed surgically. Tumour specimens were systematically reviewed; dysplastic neurofibroma was defined by the association of high cellularity and the presence of atypical cells. Clinically atypical and histopathologically dysplastic neurofibromas were analysed using Fisher's exact test. In addition, three high-grade MPNSTs were analysed retrospectively for the presence of associated histopathologically dysplastic neurofibroma. RESULTS: Among the 89 plexiform and/or subcutaneous neurofibromas surgically removed, high cellularity and cytonuclear atypia were observed in 19% and 17% of cases, respectively. Both criteria were associated in 8.9% of cases (n=8); Mib-1 immunostaining was negative in all cases (n=7). In univariate analysis, only neurological symptoms were significantly associated with dysplasia (P=0.02). Interestingly, dysplastic neurofibroma areas could be identified within or at the periphery of two MPNSTs. CONCLUSIONS: The association of hypercellularity and cytonuclear atypia could be considered as a potential histological prognostic factor of transformation leading to increased surveillance.     

A Case of Diffuse Neurofibroma of the Scalp

A neurofibroma is a benign tumor of the peripheral nerve sheath characterized by proliferation of Schwann cells, perineural cells, and endoneurial fibroblasts. Different types of neurofibromas can be identified, including localized, plexiform, and diffuse types. Neurofibromas can involve any site on the body skin. The diffuse variant is rare and occurs primarily in children and young adults. It involves the skin and subcutaneous tissue in a plaque-like fashion on the head and neck regions. We present a case of a 10-year-old boy who had a diffuse neurofibroma on the scalp.     

Pigmented neurofibroma

Pigmented neurofibroma is a rare tumour of the dermis. The clinical features and histology of a lesion occurring in a female of 69 years are described in this report. This entity was first described by Willis in 1959 in three patients with pigmented dermal tumours which showed a plexiform structure and the presence of pseudo-Meissnerian bodies.     

Solitary subungual neurofibroma: a previously unreported finding in a male patient

A neurofibroma is a hamartomatous proliferation of neuromesenchymal origin. It may be found in combination with neurofibromatosis or in the form of a solitary tumor. Clinical presentation as a solitary subungual tumor is very rare. Neurofibroma is more common in females and surgery is the treatment of choice. The present paper reports the case of a male patient with a subungual tumor on his toe. Biopsy and immunohistochemistry findings were compatible with a neurofibroma. To date, fewer than ten cases of subungual neurofibromas unassociated with von Recklinghausen's disease have been documented, this being the first case to be reported in Brazil and the only report worldwide to have described this condition in a male patient.     

头皮局限性神经纤维瘤伴脱发一例

患者,男,22岁。脱发1年余,头皮棕褐色肿物6个月。病理可见毛囊微小化,真皮下部大量细长梭形瘤细胞,波浪状排列。S-100多克隆(+),SOX-10(+),MelanA(+),Vimentin-10(+)。诊断为头皮局限性神经纤维瘤。后行手术治疗,随访中。     

Tactile corpuscle-like structures in a case of plexiform neurofibromatosis

Summary Tactile corpuscle-like structures were identified in a plexiform neurofibroma, which was localized on the right cranial hemisphere of a 16-year-old boy and had necessitated repeated surgery. These structures were studied by light and electron microscopy. The origin of their component cells is, however, still controversial. We believe to have accumulated sufficient evidence for a Schwann cell origin of these cells.Chairman: Prof. Dr. F. Seitelberger     

Plexiform neurofibroma affecting the upper parietal scalp,with cerebellar hamartoma: role of histopathology,colour Doppler imaging and magnetic resonance imaging

We report a patient with plexiform neurofibroma, which is pathognomonic for neurofibromatosis type 1 (NF1) affecting the upper parietal region of the scalp. Cerebellar hamartoma was present, a finding that, to our knowledge, has not been reported previously. We highlight the role of histopathology, ultrasonography, colour Doppler imaging and magnetic resonance imaging, in addition to the seven existing criteria, for the diagnosis of NF1.     

Plexiform spitz nevus: an intradermal spitz nevus with plexiform growth pattern

Two cases of a distinctive variant of Spitz (spindle and epithelioid cell) nevus are described. One lesion developed on the lower leg of a 17-year-old boy and the other lesion on the back of a 52-year-old man. The microscopic appearance was characterized by a plexiform arrangement of bundles and lobules of enlarged spindle to epithelioid melanocytes throughout the superficial and deep dermis. Intraepidermal melanocytic proliferation was unappreciated. Some lobules were circumscribed by a thin rim of compressed fibrous tissue. In both cases a myxoid stroma was present. The cells had abundant eosinophilic cytoplasm with well-defined borders. The nuclei were enlarged, consistently ovoid and vesicular, with small nucleoli. Both cases contained scattered multinucleate giant cells similar to those observed in classical form of Spitz nevi. No melanin pigment was detectable by light microscopy. No mitoses were observed in one case and a rare mitosis was present in the other. Tumor cells were strongly immunoreactive for S-100, but not for HMB-45, desmin, and actin. The differential diagnosis of this distinctive tumor includes desmoplastic/neurotropic melanoma, plexiform spindle cell nevus, cellular blue nevus, plexiform neurofibroma, and cellular neurothekeoma. The designation of "plexiform Spitz nevus" is chosen to emphasize its distinctive plexiform growth pattern.     

Treatment of MEK inhibitor-induced paronychia with doxycycline

A 12-year-old girl with neurofibromatosis type 1 and a large facial plexiform neurofibroma had been participating in a selumetinib clinical trial for the past 5 years. Despite decreased tumor size, she developed recalcitrant selumetinib-induced paronychia. Various antibiotics, topical medications, and surgeries were only minimally effective. Full-dose doxycycline resolved the paronychia, and sub-antimicrobial dosing has prevented recurrences for several months, permitting her to continue her selumetinib course.     

Halolike Phenomenon Around a Café au Lait Spot Superimposed on a Mongolian Spot

An 8‐month‐old Caucasian infant with neurofibromatosis type 1 presented with a congenital plexiform neurofibroma and multiple café au lait spots. A pale area surrounded one of the café au lait spots located on the left gluteus in the area of dermal melanocytosis. This halolike phenomenon results from the disappearance of the Mongolian spot around the café au lait spots, revealing normal pigmented skin. This sign has been described rarely in the literature and the pathogenic mechanism is unclear.