Congenital melanocytic nevus with features of hybrid schwannoma/perineurioma.

Neural differentiation by melanocytic nevi represents a well-recognized phenomenon, and melanocytic nevi with perineurial differentiation have been reported recently. We reported a case of a congenital melanocytic nevus with histopathologic features of hybrid schwannoma/perineurioma. The patient was a 36-year-old male who presented with a black tumor on his arm since birth. Histopathology showed a congenital melanocytic nevus in the superficial dermis, but more strikingly, in continuity with the melanocytic nevus, there was a well-circumscribed but unencapsulated nodule in the deep dermis. The nodule was composed of cellular and myxoid areas with storiform, laminated or whorled growth patterns. The cellular area was mainly composed of proliferation of plump spindle, oval or epithelioid cells. The myxoid area was mainly composed of proliferation of slender spindle cells with mucin deposition. Immunohistochemical stains showed that the cellular area was positive for S100 and CD34, weakly positive for EMA, negative for Glut-1 and collagen IV, the myxoid area was positive for S100, negative for CD34, strongly positive for EMA and focally positive for Glut-1 and collagen IV. Our results show that congenital melanocytic nevi may show neural differentiation with histopathologic features of hybrid schwannoma/perineurioma.

Schwannoma of the hand in an infant: case report.

Schwannomas (neurilemmomas) are the most common benign tumors of peripheral nerves and originate from the myelinating cells of the nerve sheath. We present a case of congenital schwannoma of the hand.

Congenital plexiform schwannoma of the clitoris.

Schwannomas are slow-growing nerve sheet neoplasms which are rarely found in the female genital system. In this article, we present a patient with Antony A congenital plexiform schwannoma of the clitoris. A 6-year-old girl was brought to our hospital with the history of a firm non-cystic clitoral mass from birth, which had been growing more rapidly during the previous year. The patient was scheduled for surgery. Histological studies revealed plexiform schwannoma of the clitoris post-operatively. Therefore, schwannoma should be considered in the differential diagnosis of clitoral masses.

[Laryngeal schwannomas]. / Schwannomes du larynx.

Laryngeal schwannoma is a rare benign tumour of the larynx. Schwannomas derive from the Schwann cells. The majority occurs in supraglottic area and may arise at any age. Magnetic resonance imaging (MRI) is the best imaging tool for suggesting the diagnosis in the appropriate clinical context. Conservative surgery is the treatment of choice. These tumors have to be distinguished from neurofibromas. We report 2 cases of laryngeal schwannoma. The first one concerned an 8-month-old baby with a laryngeal stridor history which seemed to be related to laryngomalacia. The second case was a 22-year-old man with a 5-year history of dysphonia. On nasofibroscopic examination, a sub mucosal mass enlarged the posterior part of the right false vocal cord in both cases. Both CT scan and MRI sequences showed a well margined lesion in the same place. Histological biopsies identified a schwannoma. External surgeries were subsequently and successfully performed. Diagnosis (imaging), specific treatment (endoscopic or external surgery), and possible association of laryngeal schwannomas are discussed.

Congenital and childhood plexiform (multinodular) cellular schwannoma: a troublesome mimic of malignant peripheral nerve sheath tumor.

We present six cases of a plexiform nerve sheath tumor of childhood that previously had been designated a form of malignant peripheral nerve sheath tumor (MPNST), and we provide evidence that such tumors are in fact benign plexiform cellular schwannomas. At presentation, the four girls and two boys ranged in age from 2 to 15 months with tumors of the leg (four), deep groin and upper thigh (one), and pelvis (one). Of the six lesions, five were congenital and none was associated with type 1 neurofibromatosis. Tumor sizes ranged from 2.0 to 9 cm, with three larger than 5 cm. Three tumors were well circumscribed, two were purely infiltrative, and one had a mixed circumscribed and infiltrative growth pattern. Peripheral nerve involvement was evident in two cases. Grossly, the tumors were multinodular or plexiform in configuration and, on sectioning, lobulated and homogeneously tan without necrosis. Characteristic histologic features included hypercellularity, composition of cells spindle in shape with elongate hyperchromatic nuclei, and indistinct cellular outlines. Their nuclei varied minimally in size and shape but were at least three times the size of typical neurofibroma nuclei. Mitoses were seen in every tumor and in the areas of greatest proliferative activity ranged from 4 to 31/10 high power fields. MIB-1 staining of at least 30% of the cells was noted in three cases. In five cases in which p53 immunoreactions were performed, no nuclear staining was evident. That the tumors are schwannomas was evident from their uniform strong staining for S-100 protein and an ultrastructure in all five cases showing only differentiated neoplastic Schwann cells. Architecturally, the tumors differed from conventional schwannoma and nonplexiform cellular schwannomas by their lack of both well-formed capsules and degenerative changes. Follow-up was available in all cases and ranged from 2 to 13.6 years. All tumors recurred locally and were treated by local resections. With the exception of one child lost to follow-up at 25 months, all the children are alive and free of disease. Our data combined with cases previously reported by Meis-Kindblom and Enzinger show a childhood peripheral nerve tumor unassociated with type 1 neurofibromatosis, occurring most commonly in infants, often presenting as a congenital tumor and, though prone to local recurrence, having no metastatic potential. The behavior is that of a benign tumor, although its often rapid growth, hypercellularity and increased mitotic activity, sometimes locally aggressive behavior, and difficulties encountered in obtaining tumor-free margins are unsettling to pathologist and clinician alike. These features may lead to a misdiagnosis of malignancy, which could result in harmful overtreatment.

Congenital intra-extracranial dumbbell schwannoma of temporal fossa unassociated with any major cranial nerve.

Intracranial schwannomas commonly arise from the vestibular nerve and less commonly from other cranial nerves. On rare occasions, they may be intraparenchymatous, intraventricularor intrasellar. However, the occurrence of a congenital solitary intracranial extradural schwannoma unrelated to any cranial nerve in the absence of von Recklinghausan's syndrome is exceptional. The authors report a unique, heretofore unreported case of a congenital temporal extradural schwannoma, unassociated with any known cranial nerve and with a transcranial extension presenting as a temporal fossa mass since birth in a 16-year-old female patient. Total resection of this tumour was uncomplicated. A brief review of the relevant literature is presented.

Trigeminal neurinomas in infants: report of two cases.

Two cases of trigeminal neurinoma in two infant girls aged 3 and 6 months are reported. Both presented with temporal cranial vault bulging at birth. The 6-month-old patient suffered onset of focal fits 1 month before admission and her neurological examination revealed no abnormalities. The 3-month-old patient had right exophthalmus and a subcutaneous fronto-orbital plexiform neurofibroma at birth. Neurological examination disclosed a sensory deficit of the first trigeminal nerve division. She also had a family medical history of von Reckling-hausen's disease. The incidence of trigeminal neurinomas in children is reviewed. The patients in these two cases are the youngest recorded; the cases are the only ones reported in infants. Clinical, radiological, and therapeutic aspects are discussed.

Melanose neurocutânea com malignizaçäo para sarcoma neurogênico - schwannoma maligno / Neurocutaneous melanosis with malignization to neurogenic sarcoma - schwannoma malignant

A melanose neurocutânea (MNC) é uma síndrome congênita rara, näo familiar, caracterizada por nevos pigmentados gigantes ou múltiplos e melanose do sistema nervoso central (SNC). Os autores descrevem um caso de MNC onde, além da presença dos nevos melanocíticos gigantes e múltiplos e melanose do SNC, houve malignizaçäo do componente cutâneo para schwannoma maligno com metástases pulmonares e hepáticas

Gingival granular cell tumors of the newborn. An ultrastructural and immunohistochemical study.

Gingival granular cell tumor of the newborn, or congenital epulis, is a rare congenital lesion of uncertain histogenesis located exclusively on the alveolar ridge with marked predilection for female infants. Although histologically similar to the more ubiquitous granular cell tumor or myoblastoma, ultrastructural and immunohistochemical studies support separate histogenetic pathways for the two lesions. A newborn female infant with three gingival granular cell tumors is described herein along with immunohistochemical and ultrastructural observations. There was positive immunostaining for vimentin but staining for S100 protein was uniformly negative. Immunocytochemical assay for estrogen and progesterone receptors was also negative. The findings indicate a mesenchymal origin and the demonstration of intermediate filaments with fusiform electron densities suggests that some of the granular cells have morphologic attributes of myofibroblasts.

Congenital neural hamartoma ("fascicular schwannoma"). A light microscopic, immunohistochemical, and ultrastructural study.

A previously undescribed form of a congenital neural hamartoma composed entirely of Schwann cells in a fascicular pattern was found on the leg of a male infant. The lesion was thought to be an unusual variant of plexiform Schwannoma or a newly recognized unencapsulated form of Schwannoma. On light microscopic examination, the lesion, which measured 5 x 4 cm when it was surgically removed when the infant was 7 months old, showed an unencapsulated dermal mass composed of fascicles of spindle cells with frequent Verocay body-like structures. The intervening stroma was collagenous and contained an increased number of mast cells. Special stains did not demonstrate any axons in the tumor. There was a strongly positive immunohistochemical reaction for S-100 protein and collagen type IV in the spindle cells. These cells were weakly or focally positive for Leu-7 and vimentin, and completely negative for neural filaments, neuron-specific enolase, glial fibrillary acidic protein, epithelial membrane antigen, desmin, and muscle-specific actin. On electron microscopic examination, the spindle cells were found to be surrounded by basal lamina and showed frequent cytoplasmic invagination filled with collagen bundles. No unmyelinated nerve fibers were identified.

Congenital supratentorial and infratentorial peripheral neurogenic tumor: a clinical, ultrastructural, and immunohistochemical study.

Congenital neoplasms of the central nervous system are extremely rare, although they have been well documented since the earliest reports from the mid-19th century. Medulloblastoma, other primitive neuroectodermal tumors, and various types of gliomas have comprised the majority of cases. This report describes a highly unusual infratentorial and supratentorial tumor presenting as a scalp mass in a neonate who experienced in utero distress. The supratentorial mass extended through a defect in the skull to the parietooccipital lobe, and the infratentorial aspect involved the 9th and 10th cranial nerves in the region of the cerebellopontine angle. A complex spindle cell neoplasm incorporating peripheral nerve sheath and vascular characteristics was further characterized by electron microscopy and immunohistochemistry. Based upon these studies, the tumor was interpreted as a congenital schwannoma with divergent vascular differentiation. The child has been tumor-free for approximately 2 years after the initial operative procedure.

The effect of nerve growth factor and antibodies to nerve growth factor on ethylnitrosourea-induced neoplastic proliferation in rat trigeminal nerves.

Sprague-Dawley (CD) rats were injected intravenously with ethylnitrosourea at a dose of 20 mg/kg on day 20 of gestation. This exposure resulted in early neoplastic proliferation or development of a neurinoma of the trigeminal nerve in 58% of the offspring at 90 days of age. Implantation of osmotic microinfusion pumps containing 2.5S nerve growth factor prior to ethylnitrosourea administration significantly reduced the incidence of early neoplastic proliferation. Postnatal implantation of microinfusion pumps containing 2.5S nerve growth factor also resulted in a significant but less pronounced reduction of early neoplastic proliferation. Immunoglobulin G directed against nerve growth factor (anti-nerve growth factor) did not influence the incidence of early neoplastic proliferation when administered via microinfusion pumps implanted on day 15 postnatally. These findings suggest that nerve growth factor has a protective effect on the developing nervous system against ethylnitrosourea-induced carcinogenesis.