Nasser Said-Al-Naief

Reconstruction of the Maxilla and Mandible With Particulate Bone Graft and Titanium Mesh for Implant Placement

PURPOSE The purpose of the study was to evaluate the magnitude of ridge augmentation with titanium mesh, overall graft success, anatomic location of ridge defects and their relationship to mesh exposure. MATERIALS AND METHODS This retrospective study evaluated 44 patients who received mandibular or maxillary reconstruction with autogenous particulate bone graft and titanium mesh for the purpose of implant placement. Autogenous bone graft was harvested from the iliac crest, tibia, and mandibular symphysis. A total of 45 sites were included in the study. Average augmentation bone heights were measured and compared. Statistical analysis was done with ANOVA and Students t test. Histomorphometric analysis was performed on the soft tissue specimen found between the mesh and the bone graft. RESULTS Twenty-nine sites underwent mandibular reconstruction and 16 underwent maxillary reconstruction. The mean augmentation in partial maxillary defects was 11.33 +/- 1.56 mm, and in complete maxillary augmentation, the height achieved was 14.3 +/- 1.39 mm. In the mandible, mean increase in height for partial defects was 14 +/- 1.42 mm and for complete augmentation it was 13.71 +/- 1.14 mm. The mean augmentation for all sites was 13.7 mm (12.8 mm in the maxilla and 13.9 mm in the mandible). A total of 82 implants were placed in the maxilla and 92 implants were placed in the mandible. In the maxillary group, 7 sites had exposure of the titanium mesh and 16 sites were exposed in the mandible. The success of the bone grafting procedure was 97.72%. CONCLUSIONS Porous titanium mesh is a reliable containment system used for reconstruction of the maxilla and the mandible. This material tolerates exposure very well and gives predictable results.

Molecular mechanism of the bifunctional role of lipopolysaccharide in osteoclastogenesis.

Lipopolysaccharide (LPS), a common bacteria-derived product, has long been recognized as a key factor implicated in periodontal bone loss. However, the precise cellular and molecular mechanisms by which LPS induces bone loss still remains controversial. Here, we show that LPS inhibited osteoclastogenesis from freshly isolated osteoclast precursors but stimulated osteoclast formation from those pretreated with RANKL in vitro in tissue culture dishes, bone slices, and a co-culture system containing osteoblasts, indicating that RANKL-mediated lineage commitment is a prerequisite for LPS-induced osteoclastogenesis. Moreover, the RANKL-mediated lineage commitment is long term, irreversible, and TLR4-dependent. LPS exerts the dual function primarily by modulating the expression of NFATc1, a master regulator of osteoclastogenesis, in that it abolished RANKL-induced NFATc1 expression in freshly isolated osteoclast precursors but stimulated its expression in RANKL-pretreated cells. In addition, LPS prolonged osteoclast survival by activating the Akt, NF-κB, and ERK pathways. Our current work has not only unambiguously defined the role of LPS in osteoclastogenesis but also has elucidated the molecular mechanism underlying its complex functions in osteoclast formation and survival, thus laying a foundation for future delineation of the precise mechanism of periodontal bone loss.

Synovial Sarcoma: Clinicopathologic Features, Treatment, and Prognosis

Synovial sarcoma is a characteristic subtype of soft tissue sarcomas with a predilection for young people. There may be a long delay in diagnosis or misdiagnosis, because of its insidious growth, varied presentation on imaging studies and associated joint pain, which can be confused with trauma. Diagnosis requires a tissue sample in the form of a needle or open biopsy. The needle biopsy may not be representative of the tumor, particular if it is biphasic, and it may be necessary to proceed to open biopsy. Ideally, the biopsy should be performed by the surgeon who will be performing the definitive surgical resection. Although treatment is predicated on surgery, adjuvant radiation and/or chemotherapy may be beneficial, particularly in high risk patients. Significant prognostic factors include: size > 5 cm, deep-seated location, adequacy of surgical margins, and history of recurrence. In the future, multi-institutional prospectively randomized, controlled studies will be needed to better define the role of adjuvant chemotherapy. Currently, outcome may be optimized by early suspicion and detection with referral to an orthopedic oncology specialist prior to the biopsy.

Estrogen and progesterone receptor expression is not always specific for mammary and gynecologic carcinomas: a tissue microarray and pooled literature review study.

Given their frequent expression in breast and gynecologic carcinomas, the National Comprehensive Cancer Network has recommended that the immunohistochemical expression of estrogen (ER) and/or progesterone (PR) receptors in a carcinoma of unknown primary can be used to support a breast or gynecologic origin. Several reports in the literature, however, have described such expression in a variable proportion of nonmammary and nongynecologic carcinomas. The aim of this study was to systematically evaluate the immunohistochemical expression of ER and PR on tissue microarray sections representing 348 nonbreast or gynecologic and nongynecologic tumors of lung, esophageal, gastric, pancreatic, colonic, renal, or bladder origin. We also performed a pooled analysis of the published literature in this regard. Except for 1 (2.5%) out of 40 pancreatic adenocarcinomas that expressed PR, there was no ER or PR expression in any of the other tumors evaluated by immunohistochemistry. A pooled literature review demonstrated that most of the evaluated tumors express ER and/or PR in up to 3% of cases, whereas some lung and bladder carcinomas showed such expression in around 10% of cases. This literature review also demonstrated that the frequency of ER and PR expression was dependent on the antibody clone used. Given that ER and PR expression can occasionally be seen in carcinomas of nonmammary/nongynecologic origin, we conclude that the diagnosis of metastatic breast, ovarian or endometrial carcinoma in a carcinoma of unknown primary should not be based solely on such expression.

Ameloblastoma: a multicentric study

OBJECTIVE The objective of this study was to supplement the current ameloblastoma database by reporting the clinicopathologic features of ameloblastoma from Asia and North America. MATERIALS AND METHODS Biopsy records of the participating institutes were reviewed for lesions diagnosed as ameloblastoma during the years 1993 to 2009. Slides were reclassified according to the World Health Organization Classification of Odontogenic Tumors in 2005. Clinical information and radiographic features were collected and analyzed. RESULTS The mean age of the patients ± SD was 38.27 ± 17.78 years; 662 patients (51.36%) were men. Mandible (84.26%) outnumbered maxilla and other locations combined in all countries. The number of multilocular radiolucencies (43.40%) was comparable with that of unilocular radiolucencies (42.04%). Follicular pattern was the most common histopathologic pattern (27.70%), followed by plexiform (21.10%) and unicystic pattern (20.71%), respectively. CONCLUSIONS The clinicopathologic features of ameloblastomas in the present study show some similarities with previous studies; however, minor differences exist.

Ameloblastic fibro-odontoma: expansile mixed radiolucent lesion in the posterior maxilla: a case report

Ameloblastic fibro-odontoma (AFO) is a benign tumor that displays properties of both ameloblastic fibroma and compound odontoma. Often, AFO presents clinically as a hamartoma or immature odontoma; however, the tumor can also present with progressive growth causing bone destruction and significant deformity, acting more like a true neoplasm. We report a case of a locally aggressive AFO in the posterior maxilla of a 7-year-old girl and discuss the clinical, radiographic, histopathologic, and conservative therapeutic approach to this locally aggressive tumor.

Sinonasal teratocarcinosarcoma: report of a case with review of literature and treatment outcome

Sinonasal teratocarcinosarcoma is a highly malignant, polymorphous neoplasm that combines features of carcinosarcoma and teratoma. We describe the clinicopathologic features and management of a well-documented example of this unique entity that involved a 41-year-old Hispanic man. The patient presented with a history of multiple episodes of epistaxis, nasal obstruction and frontal headaches. Computerized tomography scans and magnetic resonance imaging revealed a large mass filling the left nasal cavity and extending to the cribriform plate with involvement of the ethmoid sinuses, lamina papyracea, and orbit. The patient underwent a complex procedure for a T3N0 tumor. Histologic examination revealed a heterogeneous admixture of epithelial, mesenchymal, and neuroepithelial elements. The mesenchymal components consist of fibrous stroma and myxomatous areas, labeled with calponin and smooth muscle actin. The epithelial components vary from clear cells, nonkeratinizing epithelium to glandular pattern, and keratin containing cysts. Immature neuroepithelium and olfactory neuroblastomalike tissue are highlighted with neuroendocrine markers. Postoperatively, the patient had a rapid local recurrence of the tumor and underwent reexcision, and was treated with radiotherapy and chemotherapy. Twelve months after his primary resection, computerized tomography scans revealed an intrathoracic tumor with dominant mass in the left hilum and metastases to the mediastinum, left pleural space, and both lungs. The histologic nature of his chest mass remains undetermined. Among 54 cases of reported sinonasal teratocarcinosarcoma, 67% of patients with initial single surgical resection and 80% of patients primarily treated with radiotherapy had recurrence, or metastatsis, or unresponsiveness to treatment. The high rate of local recurrence and metastasis is indicative of its highly aggressive biologic behavior. Almost half of the patients died of tumor within 3 years of diagnosis, despite aggressive therapy. Seventy percent of the patients who survived more than 1 year had the initial therapeutic regiments of combined surgery and adjuvant therapies, suggesting that aggressive therapeutic approaches may improve the treatment outcome.

Head and Neck Mucosal Malignant Melanoma: Clinicopathologic Correlation With Contemporary Review of Prognostic Indicators

Unlike their cutaneous counterparts, head and neck mucosal malignant melanomas (HNMM) behave much more aggressively and their prognostic markers have not been fully elucidated. Therefore, the aim of this study was to review the clinicopathologic features of a contemporary series of primary HNMM, retrieved from archival material of 2 large medical centers, and to explore the association, if any, between these variables, the clinical features, and outcomes. The clinicopathologic, radiographic, and follow-up information as well as the dominant histologic pattern, mitotic rate, presence/absence of pigmentation, necrosis, ulceration, vascular invasion, and host-associated lymphocytic response were retrieved and recorded. Twenty cases were identified including 1 melanoma in situ. Eight-five percent of tumors arose in the sinonasal tract and 3 (15%) in the oral cavity. After a median follow-up of 25 months, all patients with invasive melanoma developed recurrence and/or metastasis. Local recurrences occurred in 82% of the patients after a median of 12 months, and distant metastasis occurred in 71% of the patients after a median of 13 months. Of those with adequate follow-up, 82% died with disease, and the remaining 3 had recurrent or metastatic disease. Fourth-seven percent of tumors were pigmented, 89% showed at least focal necrosis, and 93% demonstrated ulceration. Sixth-eight percent showed vascular invasion and 63% had a brisk host lymphocytic response. Mitotic rates ranged from 2 to 60/10 high-power fields. The absence of an invasive component might be associated with a better prognosis but other clinical and pathological features that predict outcome, and/or could influence therapy, remain to be determined in HNMM.

Hereditary Paraganglioma of the Nasopharynx

Head and neck paragangliomas are rare neuroendocrine tumors derived from neural crest cells of parasympathetic ganglia or the widely dispersed neuroendocrine cells of the head and neck region. Paragangliomas of the sinonasal tract and nasopharynx are rare. The clinicopathologic features of this unique example of a hereditary, nasopharyngeal paraganglioma, and selective entities that are included in its differential diagnosis are presented.

Odontogenic tumors for general pathologists

The process of tooth formation (odontogenesis) encompasses complex processes, which combine two principal phenomenons: cellular morphodifferentiation and histodifferentiation. Epithelial odontogenic tumors, in essence, recapitulate odontogenesis at various stages of development and are histologically related to remnants of odontogenic epithelium, left behind near the crown and root portions, following the cessation of this complex and detailed process. Theoretically, odontogenic tumors may develop from these rests or any of the cells that contributed to the process of odontogenesis.