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A case is presented of a neurofibroma of the mandible without recurrence 6 years after surgery. Search for neurofibromatosis was negative. Eradication of the tumor was explained by the extent of the operation that was performed.
An automated technique for segmentation and volumetric measurement of plexiform neurofibromas (PN) in neurofibromatosis 1 using short T1-inversion recovery magnetic resonance images is presented. The algorithm described implements heuristics derived from human-based recognition of lesions. This technique combines region-based with boundary-based segmentation. Two observers, who performed semi-automated volume calculations and manual tracings to estimate tumor volume, validated this method on 9 PNs of different size and location. This automated method was reproducible (coefficient of variation 0.6-5.6%), yielded similar results to manual tumor tracings (R = 0.999) and will likely improve the ability to measure PNs in ongoing clinical trials.
Apolipoprotein D (apoD) expression was studied in nonneoplastic peripheral nerve, neurofibromas (NFs), and malignant peripheral nerve sheath tumors (MPNSTs) by quantitative polymerase chain reaction, in situ hybridization, and immunohistochemistry. Multiplex quantitative polymerase chain reaction for messenger RNA was performed on a series of formalin-fixed and paraffin-embedded specimens that included 9 MPNSTs, 12 NFs, and 4 normal peripheral nerves. The average apoD expression was 108-fold decreased (DeltaCt = -7.3) in the MPNSTs compared with the NFs (P < .05). ApoD expression levels were 3.0-fold elevated (DeltaCt = 1.7) in the NFs compared with nonneoplastic peripheral nerve (P < .05). In situ hybridization for apoD RNA was performed on a separate series of 10 cases in which each microscopic section included both MPNST and the NF from which it arose. These studies confirmed elevated apoD expression in NFs compared with MPNSTs and demonstrated that this expression was variable among individual cells within the NFs. Differential expression by immunohistochemistry could only be demonstrated in selected areas, most likely because apoD protein is a small molecule that is secreted out of the cell into the extracellular space and plasma. ApoD expression initially increases a small amount with the formation of NFs from nonneoplastic peripheral nerve and subsequently decreases markedly as NFs transform into MPNSTs. This expression pattern may serve as a marker for cell cycle inhibition during peripheral nerve tumorigenesis.
A 43-year-old man with neurofibromatosis and tracheal neurofibroma of the mid-trachea and respiratory difficulty was brought to the operating room for tracheostomy. After talking to the surgeons and viewing the computerized axial tomography, tracheal intubation was done under local anesthesia. Then, general anesthesia was provided for biopsy and debulking of the tumor, followed by tracheostomy. The patient had a number of surgeries later and the trachea was decannulated.
Solitary neurofibroma unassociated with neurofibromatosis type I (NFI) arising within the scrotum is an extremely rare benign tumor. There are 8 cases reported in the literature with only 1 that occurred in childhood. In the current report the authors describe an additional adolescent patient, the second case encountered in childhood and the ninth case reported in the literature, together with a review of the related articles.
In the course of assessing the cellular composition of intraoral neurofibroma (NF), we encountered a unique gingival tumor of putative perineurial (PN) origin. The lesion showed the ordinary light microscopic NF pattern, but the ultrastructural features of well-differentiated PN cells as well as an epithelial membrane antigen (EMA)-positive, S-100 protein-negative immunoprofile confirmed the diagnosis of soft tissue perineurioma (STP). In our small series of NF, there were three ultrastructural subtypes: Type I (common Schwann cell type), Type II (NF with a high content of PN cells) and Type III (predominantly fibroblastic NF), although inhomogeneous and overlapping assembly of cellular elements. A significant number of tumor cells in Type II showed the substantial reactivity for EMA, whereas many CD34-positive cells were noted in Type III. The present results confirm previous findings that PN lineage is an important constituent in the formation of NF and reinforce the value of electron microscopy in the diagnosis of peripheral nerve sheath tumors.
Although plexiform neurofibroma (PN) is thought to represent a benign neoplasm with the potential for malignant transformation (malignant peripheral nerve sheath tumor; MPNST), its neoplastic nature has been difficult to prove due to cellular heterogeneity, which hampers standard molecular genetic analysis. Its mixed composition typically includes Schwann cells, fibroblasts, perineurial-like cells, and mast cells. Although NF1 loss of heterozygosity has been reported in subsets of PNs, it remains uncertain which cell type(s) harbor these alterations. Using a dual-color fluorescence in situ hybridization and immunohistochemistry technique, we studied NF1 gene status in S-100 protein-positive and -negative cell subpopulations in archival paraffin-embedded specimens from seven PNs, two atypical PNs, one cellular/atypical PN, and eight MPNSTs derived from 13 patients, seven of which had neurofibromatosis type 1 (NF1). NF1 loss was detected in four of seven PNs and one atypical PN, with deletions entirely restricted to S-100 protein-immunoreactive Schwann cells. In contrast, all eight MPNSTs harbored NF1 deletions, regardless of S-100 protein expression or NF1 clinical status. Our results suggest that the Schwann cell is the primary neoplastic component in PNs and that S-100 protein-negative cells in MPNST represent dedifferentiated Schwann cells, which harbor NF1 deletions in both NF1-associated and sporadic tumors.
Patients with neurofibromatosis 1 (NF1) are predisposed to develop multiple neurofibromas (NFs) and are at risk for transformation of NFs to malignant peripheral nerve sheath tumors (MPNSTs). Little is known, however, about the biological events involved in the malignant transformation of NFs. We examined the CDKN2A/p16 gene and p16 protein in NFs and MPNSTs from patients with NF1. On immunohistochemical analysis, all NFs expressed p16 protein. The MPNSTs, however, were essentially immunonegative for p16, with striking transitions in cases that contained both benign and malignant elements. None of the benign tumors had CDKN2A/p16 deletions, whereas three of six MPNSTs appeared to have homozygous CDKN2A/p16 deletions. Methylation analysis and mutation analysis of CDKN2A/p16 in MPNSTs did not reveal any abnormalities. These results show that malignant transformation of NF is associated with loss of p16 expression, which is often secondary to homozygous deletion of the CDKN2A/p16 gene. The findings suggest that CDKN2A/p16 inactivation occurs during the malignant transformation of NFs in NF1 patients and raises the possibility that p16 immunohistochemistry may provide ancillary information in the distinction of NF from MPNST.
Benign esophageal tumors occur infrequently, with leiomyomas accounting for approximately 70% of cases. Benign neural tumors of the esophagus account for 200 cases reported in the literature and rarely require operative resection. The case of a 58-year-old woman with a 4-month history of progressive dysphagia and odynophagia is presented. A large intramural esophageal mass was resected through a right thoracotomy, and the esophagus was primarily repaired. Histologic examination revealed a neurofibroma.
Seven peripheral deep-seated neurofibromas in five patients were examined by computed tomography (CT). This proved to be the most helpful investigation for demonstrating the precise size, shape and localisation of the lesion prior to surgery. In some cases CT may suggest the correct diagnosis where this has not previously been considered.
Immunohistochemical analysis of five paraffin wax-embedded neoplasms was performed to elucidate the characteristics of bovine nervous-tissue tumours. In case 1 (peripheral neuroblastoma), the neoplastic tissue was characterized by the formation of true and Homer-Wright rosettes and the existence of neuron-specific enolase. The neoplastic cells were possibly more immature than those of common neuroblastomas, because similar features are observed in human malignant neuroepitheliomas. The neoplastic cells in case 2 (ganglioneuroblastoma) ranged from large cells with abundant neurofilaments to immature small cells, rarely with neurofilaments or glial fibrillary acidic protein (GFAP). Such expression suggests the presence of pluripotential cells. The neoplastic tissue in case 3 (anaplastic ganglioglioma) was strikingly polymorphous, and had five elements; neuronal, astrocytic, oligodendrocytic, spindle cell and small oval cell. The neoplastic neurocytes and astrocytes were, respectively, characterized by neurofilament and GFAP positivity. The neoplastic oligodendrocytes made a honeycomb appearance, and the neoplastic spindle cells and small oval cells were considered to be less differentiated. The tumours of cases 2 and 3, which contained poorly differentiated cells and revealed both neuronal and glial differentiation, may be specific to calves. In case 4 (schwannoma), almost all the neoplastic cells were positive for S100 protein, while S100-negative fibroblasts were present in many areas of case 5 (neurofibroma). These two tumours were readily distinguished histologically and immunohistochemically.
We report a case of solitary neurofibroma of the scrotum. These tumors, which arise from perineural and Schwann cells, commonly occur throughout the body but they rarely have been reported to originate in the scrotum. No stigmata of von Recklinghausen's disease were identified.
A case of an intratesticular myxoid neurofibroma is reported. These tumors, which arise from perineural and Schwann cells, commonly occur throughout the body but have not been reported previously to originate within the testis. The mucoid material within the tumor is translucent, which may confuse the diagnosis with that of a hydrocele.
Neurofibromatosis is a hamartomatous disorder of neural crest derivation characterized by cutaneous pigmentation and tumor formation in various tissues. Visceral involvement is typically insidious, progressive, and difficult to treat. Plexiform neurofibroma of the urinary tract is rare. Involvement of nearly every genitourinary structure by these lesions has been reported, with the bladder being most commonly involved. In part due to the small number of patients seen at any one institution and the highly variable location and extent of this disease process, a plan for management of individuals with genitourinary neurofibromatosis has not been proposed. In an attempt to define specific goals in treatment of such patients, we reviewed our population of 260 pediatric patients with type 1 neurofibromatosis. We present our series of 5 patients with complex genitourinary lesions and describe specific management principles.
A 62-year-old woman presented with a solitary diffuse neurofibroma; a second recurrence showed features indicative of malignancy, but insufficient for a certain histologic diagnosis. Cytogenetic analysis revealed abnormalities previously described in malignant peripheral nerve sheath tumors and not in their benign counterparts, thus supporting the histologic suspicion of emerging malignancy.
We report four cases of neurofibromas affecting the digital nerves. Diagnosis and management are both difficult and demanding. Excision of the tumour while preserving the nerve was achieved by meticulous dissection in three out of four cases, resulting in normal sensation in two. The risk of recurrence is outweighed by the risk to sensation.
A case of left trigeminal nerve neurofibroma is presented. The location of the lesion required a multidisciplinary surgical effort for total excision. A vertical ramus osteotomy allowed access to the infratemporal space and base of skull. The frequency and clinical features of trigeminal nerve tumors are discussed.
Two cases of intraosseous neurofibromas of the mandible are presented. Only 25 cases of this tumor have been published previously. Of the present two cases, one was located at the upper border of the mandible, in the left second molar area where the tooth had been extracted 2 years previously. In the second case, the tumor presented itself as a 10 x 2 cm large destruction, mainly following the course of the alveolar nerve from the mandibular foramen to the mental foramen in the right side of the jaw. The mandibular first right molar was missing but the relationship between the extraction of the tooth and the development of the tumor could not be demonstrated. Histologically, the two tumors differed in the way that case 1 showed a conspicuous amount of delicate, wavy fibrils, some of which showed concentric lamellations resembling the pacinian corpuscle but without neurites containing nerve fiber bundles and also demonstrated a slight pleomorphism.