Two unusual vascular lesions: epithelioid angiomatous nodule and spindle cell hemangiomatosis.

This report outlines the pathologic findings of epithelioid angiomatous nodule and spindle cell hemangiomatosis and briefly discusses the list of differential diagnoses. Although prevalent in the skin, both the above acquired vascular lesions are rarely described in the oral cavity. It should be realized that their microscopic features often raise concern for malignancy.

Unsuspected small ameloblastoma in the alveolar bone: a collaborative study of 14 cases with discussion of their cellular sources.

BACKGROUND: Intraosseous ameloblastoma (IA) is the quintessence of epithelial odontogenic tumor and histologically and behaviorally defined as an undoubted neoplastic process. Current information must lead to the consensus that IA arises from the embryologic inclusions of odontogenic epithelium within the jawbone. Nevertheless, clinically oriented evidence is limited to this day. METHODS: The clinical and radiographic features, behavior, and pathology of 14 cases of small IA confined to the alveolar region were systematically examined. RESULTS: Six cases were a chance finding. There was no gender predilection and half of the lesions clustered in middle age (>40 years). The posterior region of the mandible (n = 7) and the anterior segment of the maxilla (n = 4) were favored. Five radiographic characteristics were recognized: interradicular (n = 5) and periradicular (n = 3), and periapical, residual and pericoronal (n = 2 each). They showed solid (n = 12) or unicystic (n = 2) growth pattern and 12 lesions were divided into seven follicular, three desmoplastic, and two plexiform subtypes. The main location of tumor was microscopically traceable in six cases; three interradicular type outside the periodontal ligament space and two periradicular and one periapical variants inside. CONCLUSION: By in-depth evaluation of the spatial relationship between tumor and its surrounding structure, the alveolar process, periodontal ligament space, and pericoronal area are all the likely starting points of IA. This report re-awakens the oral pathologist to the histogenetic significance of incipient IA as the only available human specimen for reappraisal of their origin.

Perivascular myoid tumors of the oral region: a clinicopathologic re-evaluation of 35 cases.

BACKGROUND: Myopericytoma (MPC) is a generic denomination to describe tumors showing differentiation toward perivascular myoid cells /myopericytes. It has been suggested that MPC forms a morphologic continuum with glomus tumor (GT), solitary myofibroma (SMF), and angioleiomyoma (ALM). This proposed relationship has not yet been assessed in the oral region. METHODS: We reviewed our 28-year experience with 35 oral tumors, originally diagnosed as ALM (n = 28), SMF (n = 4), GT (n = 2), and MPC (n = 1) to analyze their overlapping microscopic features, with the assistance of immunohistochemistry. RESULTS: Myopericytoma showed a wide range of growth patterns; concentric perivascular whorls, hemangiopericytomatous areas, glomangiopericytoma (GPC)-type vessels and leiomyomatous foci. Intravascular growth was also seen. Among 28 cases studied, three ALM were reclassified as MPC (n = 2) and SMF (n = 1), based on the present diagnostic criteria. Additional MPC-type components, at varying degrees, were similarly found in four ALM and three SMF, at least focally. One GT featured intravascular whorls of spindle cells. These four interrelated groups of tumors had in common GPC-type vasculature and intraluminal cellular proliferation was nearly ubiquitously present. Diffuse immunoreactivity for alpha-smooth muscle actin and less staining intensity of muscle-specific actin were observed in all tumors. Only ALM displayed desmin positivity of variable extent. Neither case tested expressed CD34. CONCLUSIONS: Our data matches with the recent results in extraoral sites that MPC, GT, SMF, and ALM exhibit histologic and immunohistochemical overlap with each other. A common perivascular myoid differentiation between these tumor types is further reinforced by the present oral series.

Pacinian neuroma in adipose herniation of the buccal mucosa.

An interesting case of a trauma-induced tender mass of the buccal mucosa in a 45-year-old man was presented. Following surgery, the patient was relieved from pain. Microscopically, the mature adipose tissue is unique in that it contained a single enlarged Pacinian corpuscle near the deep margin. This is the hitherto undescribed intraoral lesion of Pacinian neuroma in the herniated buccal fat pad.

Unscheduled DNA synthesis in human bronchial epithelium treated with various chemical carcinogens in vitro.

A system was developed in which organ culture of human bronchial epithelium was used in combination with autoradiography for quantitative measurement of unscheduled DNA synthesis (UDS) in bronchial epithelial cells. Human bronchi obtained at surgery were cut into small sections and treated with various carcinogens plus [methyl-3H]thymidine in short-term organ culture. Significant numbers of silver grains, indicating UDS, were detected on the nuclei of epithelial cells of human bronchi treated with carcinogens, and the numbers were proportional to the concentrations of carcinogens. In this system seven representative carcinogens induced UDS. Four active metabolites of benzo[a]pyrene, and benz[a]anthracene also were found to induce very active UDS in human bronchial epithelium. These findings suggest that human bronchial epithelial cells can repair different types of DNA modification induced by chemical carcinogens.

Unscheduled DNA synthesis in human oral mucosa treated with chemical carcinogens in short-term organ culture.

Unscheduled DNA synthesis (UDS) was investigated by autoradiography in human oral mucosa treated with 10 representative chemical carcinogens. Small sections of gingiva in short-term organ culture were exposed for 2 hours to chemical carcinogens plus [methyl-3H]thymidine. Significant numbers of silver grains, indicating UDS, were detected over the nuclei of both epithelial cells and fibroblasts. All ultimate or proximate carcinogens tested induced UDS. Of five procarcinogens tested, only benzo[a]pyrene (BP) did not induce UDS, but the more activated metabolite of BP, (+/-)-trans-7 beta-8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE I), was very effective in inducing UDS. Ultimate or proximate carcinogens induced higher levels of UDS than did procarcinogens. All the carcinogens that induced UDS showed clear dose-dependent effects. UDS levels were twofold to fivefold higher in the epithelial cells than in the fibroblasts, regardless of the type of carcinogen tested. Comparisons of the levels of UDS induced by 4-(hydroxyamino)quinoline 1-oxide, methyl methanesulfonate, or BPDE I did not reveal any significant differences. These findings indicate that human gingival epithelial UDS assay should be useful for short-term detection of environmental carcinogens that induce cancer in human oral mucosa.

Autoradiographic demonstration of DNA repair synthesis in rat tracheal epithelium treated with chemical carcinogen in vitro.

A system in which tracheal organ culture of inbred F344 rats was used in combination with autoradiography was developed for quantitative measurement of DNA repair synthesis in tracheal epithelial cells. Small sections of trachea in short-term organ culture were treated with various carcinogens plus [methyl-3H]thymidine. Significant numbers of grains, indicating DNA repair, were detected on the nuclei of epithelial cells of tracheal sections treated with carcinogens, and the numbers were proportioned to the concentrations of the carcinogens. The nuclear [methyl-3H]thymidine labeling index (S-phase index) was approximately 0.02, and this did not interfere appreciably with quantitative grain counting. This autoradiographic method is suitable for quantitative measurement of DNA repair synthesis in epithelial cells of the trachea in conditions mimicking those in vivo. These results suggest the potential use of this system for studies on the mechanism of carcinogenesis at a cellular level in keeping with recent biochemical studies on metabolism of carcinogens in respiratory organs in culture. The system may also be useful for screening environmental chemicals suspected of damaging DNA of the respiratory organs in relation to lung carcinogenesis.

Demonstration of in vivo DNA repair synthesis in mouse skin exposed to various chemical carcinogens.

Chemical carcinogen-induced unscheduled DNA synthesis in mouse skin in vivo was demonstrated with the aid of a mechanical device. An isotonic aqueous solution containing a carcinogen and [methyl-3H]thymidine was injected s.c. into an isolated portion of the skin clamped off with ring-shaped forceps. Dose-dependent unscheduled DNA synthesis was clearly demonstrated as silver grains on the nuclei of both epithelial and dermal fibroblastic cells in this portion of skin in response to treatment with methyl methanesulfonate, 1-methyl-1-nitrosourea, 4-nitroquinoline 1-oxide, and 4-hydroxyaminoquinoline 1-oxide. The range of variability was small among animals and within a single area of skin. These findings suggest that this system should be useful for quantitative measurement of unscheduled DNA synthesis in individual cells of the skin in vivo. Unscheduled DNA synthesis in response to various carcinogens was 3- to 5-fold more active in epithelial cells than in dermal fibroblastic cells. A time course study showed that active unscheduled DNA synthesis could be detected after 10 min, implying that adduct removal with resulting synthesis had occurred by this time.

Detection of chemical carcinogens by assay of unscheduled DNA synthesis in rat tracheal epithelium in short-term organ culture.

A short-term organ culture of rat tracheal epithelium was used to detect the ability of 53 chemicals to induce UDS. In this system all direct-acting compounds (ultimate or proximate carcinogens) tested induced UDS. Of 24 compounds requiring metabolism (procarcinogens), nine induced UDS, viz., 4NQO, AF-2, BP, DMN, DEN, and NP. Urethane, AAF, and 2,7-AAF induced very slight UDS. 3-Methyl-4NQO for which carcinogenicity data is incomplete as positive in our system. Among the cancer chemotherapeutic agents tested only mitomycin C induced UDS. MC and DMBA, which are known to induce cancer of respiratory organs in experimented animals, and DAB, aflatoxin B1 and Trp-P-1, which are strong carcinogens in the liver, did not induce UDS within 2 h. With the longer exposure (24 h), these carcinogens also failed to elicit UDS. All the carcinogens that induce UDS showed clear dose-dependent effects. No non-carcinogens tested induced UDS. These results suggested that this system should be useful for screening environmental chemicals suspected of damaging DNA of the respiratory organ on the basis of organotropic effects for UDS induction in cultured rat tracheal epithelium.

Juxtaoral organ of Chievitz presenting clinically as a tumour.

An extremely rare hamartomatous lesion of the juxtaoral organ of Chievitz (JOOC) in a 63 year old man is reported. The tumour appeared as a large mass in the infratemporal fossa with associated mandibular bone resorption; histologically, it was well encapsulated and composed of numerous tangled masses of benign squamous epithelial nests and mature fibrofatty tissue. There were no histological features suggestive of neoplastic transformation. A literature survey confirmed that this is the first adult case of JOOC presenting clinically as an extraoral tumour.

Sclerosing inflammatory myofibroblastic tumour of the tongue: an immunohistochemical and ultrastructural study.

A case of inflammatory myofibroblastic tumour (IMT) arising in the tongue of a 27-year-old man is described. The patient presented with a solitary, well-circumscribed submucosal mass of 4 months duration. The tumour showed in its largest part a paucicellular sclerosing lesion resembling a hyalinizing granuloma surrounded by a thin rim of an admixture of myofibroblasts, plasma cells and foamy histiocytes. Myofibroblasts expressed vimentin and alpha-smooth muscle actin positive immunophenotypes. Ultrastructurally the hyaline areas were composed of abundant collagen fibres with sparse myofibroblasts. Extensive scar-like change in this IMT may be related to a traumatic insult.

Post-traumatic spindle cell nodule misdiagnosed as a herniation of the buccal fat pad.

We studied a quasi-neoplastic lesion that developed in the oral mucosa secondarily to trauma. The female patient, 2 years of age, presented with a rapidly growing nodule and the lesion was diagnosed as a herniation of the buccal fat pad. Following partial resection, no recurrence was seen. The ulcerated polypoid mass was composed of compact spindle-cell proliferation with invasion of underlying muscle and fat. Atypical stromal cells were present in the myxoid areas. The surface edematous stroma contained abundant granulation tissue-type vascularity and a mixed population of chronic inflammatory cells. On immunohistochemical study, the spindle cells were consistent with myofibroblasts. The morphologic features, proliferating cell type, and benign clinical course are identical to the post-operative spindle cell nodules that occur in the genitourinary tract.

Intravenous myofibroblastic pseudotumour of the buccal mucosa.

An intravenous pseudotumour at a traumatised site of the buccal mucosa of a 68-year-old woman is described. The lesion was composed of reactive spindle cell proliferation, merging of haphazard bizarre cells and inflammatory elements. Cellular morphology and immunohistochemical profile of proliferating cells reflected that of myofibroblasts. Conceivably, these cells may be derived from indigenous vascular smooth muscle cells. The present case represents a unique type of a reparative process intimately related to the tissue damage.

Basaloid squamous cell carcinoma of the oral mucosa: a new case and review of 45 cases in the literature.

Basaloid squamous cell carcinoma (BSCC) of the oral mucosa other than the tongue is uncommon. We report a case of a 67-year-old man who diagnosed with Stage I BSCC in the floor of the mouth. This early stage presentation carries a considerably better prognosis. Clinical summary of 46 cases of oral BSCC indicated that the tongue base was the most preferred site (61%). The patients were 19 males and 15 females with the mean age of 61 years (n=34). Most presented with Stage III or IV disease (62%). Even at the initial presentation, 47% had cervical lymph node metastases. Its aggressive clinical behaviour was characterized by a high incidence of local recurrence (32%), regional lymph node metastases (52%), and mortality rate (38%). Because of the advanced stage at presentation, oral BSCC is prognostically worse.

Intraosseous squamous cell carcinoma arising in association with a squamous odontogenic tumour of the mandible.

We report a rare occurrence of intraosseous squamous cell carcinoma (SCC) arising in association with a squamous odontogenic tumour (SOT), which had not previously been documented in the literature. A 53-year-old man had, for 5 years, a well-demarcated radiolucency attached to the impacted third molar of the mandible. The enucleated specimen had a characteristic pattern of SOT, but in which a few epithelial islands showed atypical features suggestive of SCC. Intense p53-, proliferating cell nuclear antigen- and Ki-67-positive cells were detected in carcinoma areas. Within 2 months, aggressive bone destruction showing typical findings of intraosseous SCC appeared. The present tumour is presumably a malignant variant of SOT.

Importance of DNA repair in carcinogenesis: evidence from transgenic and gene targeting studies.

We have generated transgenic mice by introducing copies of the E. coli O6-methylguanine-DNA methyltransferase gene, ada. Liver extracts from homozygotes demonstrate about three times the control enzyme activity and increase up to about eight-fold can be induced by treatment with zinc, since the metal-responsive metallothionein promoter is attached to the ada gene. Furthermore, studies of liver carcinogenesis in our transgenic mice demonstrated significantly reduced rates of development of hepatocellular tumors after treatment with dimethylnitrosamine or diethylnitrosamine. It is well known that xeroderma pigmentosum (XP) patients are deficient in DNA repair. The availability of XPA (XP group A complementing) knockout mice has enabled us to investigate the functional role of the XPA nucleotide excision repair gene in carcinogenesis in vivo, first using the mouse skin as a model system. XPA-/- mice demonstrated skin ulcers 5-7 days after 7,12-dimethylbenz[a]anthracene (DMBA) treatment and papilloma development within 4 weeks prior to promotion, skin tumor incidence being also much higher than in heterozygous and wild-type mice. Experiments targeting the lung, liver and tongue have also been conducted to answer the question of whether the internal organs of these mice are also susceptible to chemical carcinogens. For lung carcinogenesis, mice were instilled intratracheally with a small dose of benzo[a]pyrene. The pulmonary tumor incidence in XPA-/- mice was significantly higher than in XPA+/- and XPA+/+ mice. XPA-/- mice were also found to be have enhanced sensitivity to aflatoxin B1 regarding liver tumor induction. In addition, administration of 4-nitroquinoline-1-oxide in drinking water for 50 weeks resulted in tongue tumors only in XPA-/- mice. These studies, thus, provided convincing evidence that XPA mice are also sensitive to carcinogenesis in organs other than the skin.

Gingival peripheral odontoma in an adult: case report.

BACKGROUND: Odontoma arising in the extraosseous soft tissue is extremely uncommon. We describe our experience of gingival peripheral odontoma in which the initial presentation was a small asymptomatic nodule. METHODS: Case study. RESULTS: A 44-year-old man reported with a firm gingival mass of the anterior maxilla which had been gradually enlarging over 5 years. Radiographic examination showed a dense radiopaque mass occupying most of the tumor and no evidence of underlying intraosseous lesion. The pathology was reported as odontoma. CONCLUSIONS: This is the fourth reported case of peripheral odontoma in the gingiva.

Periosteal ossifying fibroma of the palate.

An unusual case of the ossifying fibroma of a 54-year-old woman is reported. Clinically the lesion appeared as an exophytic mass on the hard palate and apparently originated outside of bone. Histologically the resected tumor is well encapsulated and made up of a richly cellular fibroblastic stroma containing foci of mature bone with a predominantly lamellar structure. While the possibility exists that the lesion is reactive, it appears to be a true neoplastic growth and a purely soft tissue process arising from the periosteum of the palate. Thus, we proposed the term periosteal ossifying fibroma for this distinct lesion in order to distinguish it from the common peripheral ossifying fibroma.