Samir K. El-Mofty

Tumors of the intraoral minor salivary glands: A demographic and histologic study of 426 cases

In a demographic and histologic study of 426 oral minor salivary gland tumors, 57.5% were classified as benign and 42.5% were classified as malignant or potentially malignant. There was an overall female preponderance (1.59/1). The mean age for females was 53.1 years and for males was 50.6 years. The mean age for patients with malignant tumors was 5.4 years greater than for patients with benign tumors and was statistically significant. The palate was the most common site for oral minor salivary gland tumors followed by the upper lip and the buccal mucosa. These three sites accounted for 76.1% of all cases. Pleomorphic adenoma was the most common benign tumor (41% of all cases and 71% of benign tumors) followed by monomorphic adenoma of the canalicular and basal cell subtypes (10% of all tumors and 18.9% of benign lesions). Mucoepidermoid carcinoma was the most commonly encountered malignant tumor, accounting for 15.2% of all tumors and 35.9% of malignant lesions. Low-grade (terminal duct, lobular, polymorphous) adenocarcinoma was the most second most common type, making up 11% of all tumors and 26.4% of all malignant tumors. The results of this study are compared with other recent studies.

A histopathologic study of 116 ameloblastomas with special reference to the desmoplastic variant

The histopathologic features of 116 ameloblastomas were reviewed with special reference to the incidence of the recently described desmoplastic variant. The series included 110 intraosseous lesions and 6 extraosseous ameloblastomas. Ninety-six (88%) of the intraosseous tumors were found in the mandible, and 61% involved the molar-ascending ramus area. Fourteen examples of the desmoplastic variant were identified, representing 13% of the intraosseous tumors. The lesions showed distinctive histologic features characterized by an extensive collagenized stroma containing small islands of tumor epithelium with scant tendency to form cystic structures. This histologic variant has a marked tendency to involve the anterior portions of the jaws with 7 of the 14 examples being located in the maxilla. These desmoplastic lesions also showed unusual radiographic findings, often more suggestive of a benign fibro-osseous lesion than of ameloblastoma.

Early Membrane Injury in Lethally Irradiated Salivary Gland Cells

The early manifestations of radiation injury in salivary glands were investigated in the rat. The animals received a single X-ray dose in the range of 200-2000 rad to their neck area. Glandular changes during the first 24 hours were studied by light and electron microscopy and by measuring serum amylase activity. The amount of cell necrosis was quantitated and expressed as necrosis index (NI), Parotid NI and serum amylase activity 24 hours following irradiation were directly proportional to the X-ray dose. The submandibular gland cells were radioresistant and so were the mucous cells of the sublingual gland. The major increase in parotid acinar cell necrosis occurred between 12 and 24 hours after irradiation. However, more than 100 per cent increase in serum amylase level was detected prior to the onset of any significant cell necrosis. As early as two hours following irradiation signs of cell membrane injury were demonstrable in the parotid by electron microscopy and consisted of intracellular oedema, sequestered degenerative cell membranes, and an accumulation of intramitochondrial particles. None of these changes was detectable in the submandibular gland. The implication of membrane injury in the lethal effects of radiation on parotid cells is discussed.

Undifferentiated carcinoma of the oropharynx: a human papillomavirus-associated tumor with a favorable prognosis

Undifferentiated carcinoma (undifferentiated carcinoma, nasopharyngeal type, or lymphoepithelial carcinoma) is an uncommon and histologically distinct tumor in the oropharynx, which in Western countries, has been clearly shown not to harbor Epstein Barr virus (EBV). We sought to analyze these tumors for human papillomavirus (HPV) and to examine their clinical outcomes. All cases of oropharyngeal carcinoma diagnosed as ‘undifferentiated’ or ‘lymphoepithelial’ were retrieved from the department files at Barnes-Jewish Hospital. After consensus review by all three study pathologists, 16 were found to have diagnostic histological features and to lack distinguishing characteristics of other oropharyngeal cancers. Immunohistochemistry for p16 and p53 and in-situ hybridization for HPV and EBV encoded small RNA were performed. p16-positive but HPV in situ hybridization-negative cases were analyzed by polymerase chain reaction for high-risk HPV types. The results were correlated with pathological findings and clinical follow up. There were 16 patients. The average age was 59.2 years, 14 patients (88%) were smokers, and 13 (81%) had nodal metastases. In all, 14 cases (88%) were p16 positive and 15 (94%) were HPV positive by in situ hybridization and/or polymerase chain reaction. All cases were negative for EBV, and p53 was overexpressed in five (33%), four of which were HPV positive. Disease recurred in only three patients and two of these died with disease at 38 and 136 months, respectively. Three year overall, disease-free, and disease-specific survival rates were 54, 78, and 100%, respectively. In summary, in our patient population, the majority of oropharyngeal undifferentiated carcinomas harbor transcriptionally active HPV but not EBV. Almost all overexpress p16, and few have p53 overexpression. Disease-specific survival is comparable to published rates for other HPV-related oropharyngeal squamous cell carcinoma variants and is better than that of HPV-negative carcinomas.

Peripheral ameloblastoma: A clinical and histologic study of 11 cases

Peripheral ameloblastoma (PA) is a rare odontogenic tumor. Previously, only 39 cases of PA had been reported in the English literature. In this article 11 additional cases of PA are presented. Concordance with previous cases was evident with regard to race, clinical appearance, and site of predilection. However, differences were observed with regard to age, sex distribution, and predominant histologic pattern. The average age in the current cases is younger, there is no male bias, and the most common histologic pattern is plexiform rather than follicular or acanthomatous. Recurrence following simple excision is rare, but has been reported. Long-term postoperative follow-up is recommended.

Epithelioid hemangioendothelioma of the oral cavity: Report of two cases and review of literature

Abstract Recently, Weiss and Enzinger 1 introduced the term epithelioid hemangioendothelioma to describe a vascular neoplasm of soft tissue characterized by a proliferation of endothelial cells with an epithelioid morphology. The biologic behavior of the tumor is “borderline” in the sense that it has an indolent course with the potential for recurrence, but rarely metastasizes. The tumor occurs predominantly in the extremities, but less frequently in the head and neck. 2–4 It also has been reported in the lung, 5–7 liver, 8–10 and bone. 11,12 Three cases have been recently reported in the oral cavity, 3,13,14 two in the gingiva and one in the palate. This is a report of two additional cases, one of the maxillary palatal gingiva and the second involving the tongue. A review of the previously reported cases is also provided.

Recurrence of cystic central mucoepidermoid tumor of the mandible. Report of a case with 3 recurrences in 7 years.

A case of a cystic central mucoepidermoid tumor of the mandible is presented. The radiographic and histopathologic manifestations of the lesion bear some resemblance to the odontogenic cyst. Conservative treatment by simple enucleation resulted in 3 recurrences in a 7-year period. En block resection of such lesions is recommended.

Extensive HPV-Related Carcinoma In Situ of the Upper Aerodigestive Tract with ‘Nonkeratinizing’ Histologic Features

Over the past several decades, it has become clear that human papillomavirus (HPV) is important for the development and progression of many head and neck squamous cell carcinomas, particularly those arising in the oropharyngeal tonsillar crypts. Yet, our understanding of HPV’s role in premalignant squamous lesions remains relatively poor. This is in part because premalignant lesions of the oropharyngeal tonsillar crypt tissue, where most HPV-related carcinomas arise, are difficult if not impossible to identify. Recent evidence does suggest a role for HPV in a subset of premalignant lesions of the surface epithelium, especially the oral cavity, despite the rarity of HPV-related invasive squamous cell carcinomas at this site. Furthermore, these HPV-related oral cavity dysplasias appear to have unique, bowenoid histologic features described as ‘basaloid’ with full-thickness loss of squamous maturation, mitotic figures and apoptosis throughout. Here, we present a unique case of an HPV-related premalignant lesion (squamous cell carcinoma in situ) extensively involving the surface epithelium of the oral cavity, oropharynx and larynx that had ‘nonkeratinizing’ histologic features typical of HPV-related invasive squamous cell carcinoma. This case was strongly p16 positive by immunohistochemistry and harbored transcriptionally active HPV as demonstrated by E6/E7 RNA in situ hybridization. Furthermore, the patient had an excellent response to radiation treatment.

Clinical evaluation of a single crystal sapphire tooth implant in human beings

Single crystal sapphire implants are commercially prepared ceramics of aluminum oxide. These endosseous implants have been placed in patients at Washington University since 1978. The course of patients has been followed closely with periodic clinical and radiographic evaluations. Sapphire is well tolerated by hard and soft tissue and provides excellent abutments for fixed partial dentures.

Intraoral manifestation of thromboangiitis obliterans (Buerger's disease)

A case of thromboangiitis obliterans (Buergers disease) showing vascular lesions in the oral cavity is presented. To our knowledge, this is the first report of involvement of branches of the external carotid artery with this disease. The clinical, radiographic, plethysmographic, and histologic features of Buergers disease are presented. Etiologic factors, pathogenesis, and treatment modalities are discussed.