Conflation of gingival overgrowth and schwannoma.

The authors describe a seminal case report of a 10-year-old boy with enlarged gingivae in relation to his maxillary anterior teeth. The lesion, provisionally diagnosed as idiopathic gingival enlargement, was completely excised and divided into two sections. The histological and immunohistochemical findings in one of the sections showed it to be characteristic of schwannoma while the other section showed indications of idiopathic gingival enlargement. The patient has been followed up carefully and no recurrence has been noted.

Morphometric study of desmosomes from oral squamous cell carcinoma.

The authors studied ultrastructural characteristics of desmosomes from oral squamous cell carcinoma, reporting the cellular differentiation and size of the desmosomes. The length of the desmosome profiles was measured with a Zeiss KS-300. The desmosomes were grouped according to their size and the tumor histological grading. Statistical analysis indicated a significant correlation (p < .001) between the size of the desmosomes and the histological grading group of the malignancy. The comparison of the desmosome size among the tumor histological grading groups also showed significant difference (p < .001). A multiple comparisons test indicated homogeneity in the size of desmosomes within the histological grading groups: 100% in the well differentiated, 95.2% in the moderately differentiated, and 50% in the poorly differentiated group. The preliminary data strongly suggest that the homogeneity of length of the desmosome profiles may be exploited for diagnostic strategies.

Congenital epulis: an ultrastructural and immunohistochemical case study.

We report a case of an otherwise healthy, two days old, female with a a mass derived from the mandible. Light microscopy findings were compatible with the diagnosis of congenital epulis. The lesion showed negative staining for S-100 protein, which is a characteristic finding in cases of epulis and distinguishes it from granular cell tumor. The characteristic electron microscopy findings, as well as other features of epulis in relation to the theories for its possible origin are also reviewed

Myofibroma of gingiva: report of a case with immunohistochemical and ultrastructural study.

Oral myofibroma is an uncommon, benign, solitary proliferation of myofibroblastic tissue. Few cases affecting maxillofacial region have been reported. We present a case of gingival myofibroma, diagnosed on clinical, histopathological, immunohistochemical, and ultrastructural basis.

Congenital malignant rhabdoid tumour of the gum margin.

The case of an infant born with a large polypoid tumour arising from the mouth is described. The tumour had the histological, immunohistochemical and ultrastructural phenotype of an extrarenal malignant rhabdoid tumour and followed an aggressive clinical course. This is one of the few reported cases of malignant rhabdoid tumour to present at birth. The oral tumour was associated with a mass in the posterior cranial fossa. This was most likely to be a simultaneous second primary tumour.

Chromosome analysis in X-irradiated primary cells of a human squamous cell carcinoma by fluorescence in situ hybridization.

Chromosomes in primary tumour cells derived from a squamous cell carcinoma of the gingival mucosa were analysed. The ploidy of individual chromosomes and the frequencies of reciprocal translocations in unirradiated and irradiated cells were assessed by the method of fluorescence in situ hybridization. Hybridization probes for whole chromosomes 1, 2, 3, 4, 9 and 12 were used. The analysis was carried out in early (1st-3rd) passage cells and for comparison, in late (25th-30th) passage cells. A radiation-induced polyploidy of all analysed chromosomes was observed in irradiated (D = 4 Gy) early as well as late passage cells, with the exception of chromosome 4 in late passage cells. Ploidy of chromosomes 1 and 4 was studied at lower doses (1-3 Gy), too. Polyploidy was observed for doses >2 Gy. Some of the analysed chromosomes showed a high 'spontaneous' translocation frequency in both types of cells. The frequencies of radiation-induced translocations were similar in early and late cells and these frequencies were not always proportional to the length of the chromosomes studied. The radiosensitivity of individual chromosomes was not correlated with the level of spontaneous translocation frequency.

Primary intraoral epithelioid hemangioendothelioma presenting in childhood: review of the literature and case report.

Epithelioid hemangioendothelioma (EH) is a recently described vascular neoplasm of borderline or intermediate malignant potential. This tumor arises from medium- to large-sized vessels, primarily involves the soft tissues of the extremities as well as the liver and lung, and rarely occurs in the head and neck region. Only eight well-documented cases of intraoral EH have been reported. We present an additional pediatric case of EH confined to the oral cavity and review the literature regarding EH presenting as an intraoral mass. EH is characterized histopathologically as an epithelioid lesion arranged in nests, strands, and trabecular patterns with infrequent vascular spaces. Occasional erythrocytes within intracytoplasmic lumina may be seen in tumor cells. Ultrastructural examination typically shows intracytoplasmic lumina with pseudopodial cellular membrane extensions. The cytoplasm usually contains intermediate filaments infrequently associated with Weibel-Palade bodies. Neoplastic cells are immunoreactive for factor VIIIR:Ag and Ulex europaeus. Histopathologic features, which may be associated with aggressive clinical behavior, include significant cellular atypia, one or more mitoses per 10 high-power fields, an increased proportion of spindled cells, focal necrosis, and metaplastic bone formation. Because of the intermediate malignant potential of epithelioid hemangioendothelioma, complete tumor resection is recommended for intraoral lesions.

Light microscopic, ultrastructural, and immunohistochemical examinations of two calcifying epithelial odontogenic tumors (CEOT) in a dog and a cat.

Two calcifying epithelial odontogenic tumors from a 10-year-old cross-breed dog and a 9-year-old cat were characterized histologically and electron microscopically. Important characteristics were plexiform to squamous epithelial structure, amyloid in the tumor tissue with partial calcification (Liesegang's rings), and a low rate of mitosis. The amyloid found in the tumors was subjected to immunohistochemical examination, using a series of antibodies (anti-AA, -AL, -AF, -ASc1, -AB, -cytokeratin, -vimentin, -desmin, -laminin). The exclusive reaction to anti-cytokeratin and anti-laminin suggests that the amyloid is of epithelial origin.

Intracytoplasmic lumina in squamous epithelial lesions of the oral cavity.

Intracytoplasmic lumina are considered a diagnostic feature of adenocarcinomas and have not been reported in squamous cell carcinomas. We are documenting intracytoplasmic lumina in a case of primary squamous cell carcinoma of the oral mucosa and in the oral squamous mucosa in two cases of graft versus host disease, confirming that intracytoplasmic lumina are also present in squamous epithelia and their tumors. Likely explanations for the presence of intracytoplasmic lumina in non-neoplastic and malignant squamous cells of the oral cavity include multiple differentiation, phagocytosis and immune attack on desmosomes.

A rare case of a multicentric peripheral ameloblastoma of the gingiva. A light and electron microscopic study.

A rare case of a multicentric peripheral ameloblastoma of the gingiva in a 54-year-old male patient is described along with a light and electron microscopic study of the excised tumors. The peripheral ameloblastoma is considered to be the gingival counterpart of the more common intraosseous ameloblastoma. Although both tumors have similar histomorphologic characteristics, their clinical appearance and behavior are completely different. The peripheral ameloblastoma is slow growing and non-invasive, and recurrence is uncommon following excision. The more common central ameloblastoma, is locally invasive and can destroy large segments of the jaw. The histogenesis of the peripheral ameloblastoma and several other odontogenic tumors of the gingiva serves to illustrate the proliferative potential of the basal cell layer of gingival epithelium.

Neuroendocrine carcinoma of the oral cavity.

We report the clinical and pathologic features of a small cell neuroendocrine carcinoma arising in the oral cavity of a 63-year-old man. The tumor stained positively with neuron-specific enolase and had dense core granules ultrastructurally. Chemotherapy ordinarily given for pulmonary small cell carcinoma induced a clinical remission. When the tumor recurred 8 mo later, focal squamous differentiation was present within the neuroendocrine carcinoma. The patient died 2.5 yr after presentation.

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 epulis--an electron microscopic observations of two cases.

Two cases of congenital epulis occurring in the gingiva at the site where the lower deciduous incisors were to erupt are described. The first patient was a 7 day-old female infant. Her epulis was diagnosed, histopathologically, as a granular cell tumor. Electron microscopy revealed that the tumor cells were large with small eccentric nuclei. The cells were filled with granular structures. These granular substances varied in size and electron density. Case 2 involved a 37 day-old male infant. A histopathological diagnosis of fibromatosis was made. Electron micrographs showed a proliferation of cells which resembled fibroblasts. These cells varied in shape, including some with thin, long processes. Abundant reticular and collagen fibers were present in the stroma. In both cases, the postoperative course was uneventful without recurrence.

Granular cell lesions of the jaws and oral cavity: a clinicopathologic, immunohistochemical, and ultrastructural study.

A clinicopathological, immunohistochemical, and ultrastructural study of 44 oral granular cell lesions was performed. A total of 35 mucosal granular cell tumors, 4 granular cell ameloblastomas, 1 lichen planus with granular cell change, and 3 congenital epulides of the newborn were studied. Pseudoepitheliomatous hyperplasia was found to occur in only a minority of these cases. Immunohistochemically, the majority of granular cell lesions were uniformly positive for S-100 protein and focally positive for vimentin in one half of the cases, suggestive of origin from a Schwann cell or a precursor mesenchymal cell. Congenital epulis of the newborn and central odontogenic granular cell tumor were negative for S-100 protein, epithelial membrane antigen (EMA), and prekeratin, suggesting a mesenchymal origin for these lesions.

Ameloblastoma of mucosal origin.

Histopathological, histochemical and ultrastructural findings of an extraosseous ameloblastoma occurring in an 89-year-old woman are reported. Rete pegs of the gingival epithelium covering the lesion showed marked extension into the lesion, and direct continuity between the extended rete pegs and tumor follicles was evident. Ultrastructural examination showed that the rete pegs gradually became transformed into double-stranded epithelial cords as they elongated deeply, and that the ends of these epithelial cords gradually became transformed into tumor follicles. These findings suggest that the potential for differentiation is maintained in the basal cells of the gingival epithelium throughout life, and can be triggered by unknown stimuli. The ultrastructure of the tumor follicles was similar to that of intraosseous follicular ameloblastoma, but was different from that of cutaneous basal cell carcinoma. Histochemical staining for keratin protein revealed that the central cells of tumor follicles and the covering epithelium were positive, whereas the peripheral cells of tumor follicles and the elongated rete pegs were negative.

Verrucous carcinoma of the oral cavity.

The clinical course and morphologic (light and ultrastructural) characteristics of a case of verrucous carcinoma of the lower gingival mucosa are presented. Clinical course of the patient was unfavorable following surgery (supposedly incomplete) and radiotherapy (6,000 R) of the tumor. The therapeutic factors that may influence an unfavourable prognosis are commented upon, especially in regard to a slow-growing neoplasm with a generally good course.

Leiomyosarcoma of gingiva: report of a case and review of the literature.

Leiomyosarcoma of the oral region has rarely been reported. A review of the literature yield only 24 cases. The histopathology with special reference to ultrastructural findings and immunohistochemical examination of an additional case of leiomyosarcoma of mandibular gingiva has been presented. The manifestation and symptoms, treatment and prognosis, and the origin of this tumor are discussed. Because of the high rate of local recurrence and metastases, extensive surgical excision and long-term follow-up are mandatory.

A transmission electron microscopic study of two cases of oral smooth muscle neoplasm.

Two cases of smooth muscle tumors that had appeared in the oral regions were examined by means of histopathology and electron microscopy. One was a case of angiomyoma that appeared in the lip of a 33-year-old man, and the other was a case of leiomyosarcoma in the maxilla of a 63-year-old woman. The results of the examination of both cases were as follows: the benign tumor (angiomyoma) was composed of mainly mature smooth muscle cells having dark cytoplasm, and the malignant tumor (leiomyosarcoma) consisted mainly of two types of cells, undifferentiated mesenchymal cells or fibroblast-like cells (type I) and myofibroblast-like cells (type II). Based upon these results, the relationship between the myogenous differentiation and the component cell types, and biological behavior of these smooth muscle tumors was discussed.

Melanotic neuroectodermal tumor of infancy with high serum levels of alpha-fetoprotein. Ultrastructural study and immunological evidence of glial fibrillary protein and alpha-fetoprotein.

We report an infant melanotic neuroectodermal tumor in the anterior part of the upper gingiva, which was associated with high urinary excretion of vanilmandelic acid. Serum levels of alpha-fetoprotein were abnormally high (200 ng/ml). They returned to normal after removal of the tumor (10 ng/ml). The tumor was characterized histologically and ultrastructurally by the presence of melanocytic and astrocytic cells containing glial fibrillary protein. Intracellular alpha-fetoprotein was demonstrated by the immunoperoxidase method (PAP) in scattered foci of interstitial cells.