PubMed Health⌕ Search

Biomedical subjects

Leon Barnes

Publications and source records attributed to Leon Barnes.

14 recordsLinked to original sources
PubMed2006

Malignant mixed tumors of the salivary gland: a study of loss of heterozygosity in tumor suppressor genes.

Carcinosarcomas and carcinoma ex pleomorphic adenoma of the salivary glands are rare tumors that fit into the broader category of malignant mixed tumors. Although most evidence has suggested that the different morphologic components arise from a common clonal origin, there are very few studies that have provided molecular evidence for this clonality. In this study, we examined a set of seven carcinosarcomas and four carcinomas ex pleomorphic adenoma for tumor suppressor gene loss of heterozygosity, in order to assess the clonal patterns in the varying components. Microdissection was performed to obtain each morphological component and tumor suppressor gene loci on 3p, 5q, 9p, 17p, 17q, and 18q were analyzed. The fractional allelic loss (FAL) was calculated for each area, and the different targets were compared for their molecular profile. The overall mean FAL of the malignant targets was 42%. In carcinosarcomas, the sarcomatous targets had a higher mean FAL than the carcinomatous targets (68 vs 46%, respectively) and in carcinomas ex pleomorphic adenoma, the mean FAL in the benign component was 11 vs 46% seen in the carcinomatous component. The most frequently lost genetic loci were p53 (17p13, 73%), nm23-H1 (17q21, 55%), and DCC (18q21, 50%). Loss of heterozygosity of 17q21 and 9p21 only occurred in carcinosarcomas and not in carcinomas ex pleomorphic adenoma. Within the carcinosarcomas, the mutational profiles were conserved between epithelial and sarcomatous areas. In carcinomas ex pleomorphic adenoma, loss of heterozygosity was uncommon in the benign component, but the mutations were conserved in the corresponding malignant areas. These results support the hypothesis that the carcinomatous and sarcomatous components of carcinosarcomas are clonally related. Furthermore, these data support prior studies that suggest a common clonal origin for the benign and malignant components of carcinomas ex pleomorphic adenoma.

Adult↗
PubMed2005

Idiopathic midline destructive disease: fact or fiction.

The differential diagnosis of a progressive destructive lesion of the midface and upper airway region includes both neoplastic and non-neoplastic entities; of these, the majority of cases prove to be either Wegener's granulomatosis or lymphoma. Historically, these sorts of necrotizing midfacial lesions were diagnosed clinically, and as a consequence a variety of overlapping categories of disease sprang up. As pathologic examination of biopsy material became both more widespread and (particularly in the last several years) more sophisticated, many lesions previously thought to be of mysterious origins have proven to be examples of lymphoma (in particular, sinonasal natural killer cell or T cell [NK/T] lymphomas). At present, the evaluation of a patient with a progressive destructive process involving the midface region should include imaging studies (to delineate the extent of disease) as well as biopsy (with sampling of lesional tissue for application of sophisticated testing--including immunohistochemical studies, flow cytometry, or molecular studies as necessary--to exclude the possibility of a NK/T cell lymphoma). There remain occasional patients whose necrotizing midfacial lesions continue to be difficult to classify despite the application of extensive testing; such patients are sometimes described as suffering from the nebulous entity of "idiopathic midline destructive disease". While it remains to be seen whether such patients will ultimately be assigned to other diagnostic groups (as, for example, occult toxic injuries--as in the case of cocaine abusers who are not forthcoming with regard to their drug usage), it seems likely that "idiopathic midline destructive disease" is a diagnostic term of questionable validity which should be used only with extreme reticence in modern practice.

Diagnosis, Differential↗
PubMed2005

Allelic loss in parathyroid neoplasia can help characterize malignancy.

Parathyroid carcinoma can be difficult to diagnose, and the final pathologic diagnosis relies on clinicopathologic correlation. Clinical features of malignancy include high preoperative calcium levels and an intraoperative impression that the gland is adherent to local structures. Histologic features of malignancy include increased mitoses, vascular invasion, and broad bands of fibrosis. This study used molecular genotyping to assess parathyroid neoplasia for loss of heterozygosity across a panel of known tumor suppressor genes that have been previously identified as being important in the pathogenesis of parathyroid diseases. Parathyroid adenomas, hyperplasia, and carcinomas were included in the study, and a fractional allelic loss was calculated for each lesion. Losses of 1q25, 7q13.3, 10q23, 13q14.3, and 11p15.5 were particularly prevalent. In addition, almost all adenomas and carcinomas had loss of the markers for 1p. The benign parathyroid diseases (adenomas and hyperplasia) had low mean fractional allelic loss (11% and 15%, respectively). The parathyroid carcinomas, in contrast, showed high mean fractional allelic loss (63%). This difference in the mutational profile suggests that this type of assay may be useful as an adjunctive diagnostic test in cases of parathyroid neoplasia.

Adenoma↗
PubMed2004

Giant cell tumor of the skull: a case report and review of the literature.

BACKGROUND: Giant cell tumors are benign lesions that typically occur at the epiphyses of long bones that typically present with pain or swelling. Most data on giant cell tumors in the skull consist of case reports, and many large series of giant cell tumors have no examples in the skull. METHODS: We report a case of giant cell tumor of the skull and review the literature on these lesions. RESULTS: A 24-year-old woman presented with localized tenderness and mild swelling over the left inferior parietal and occipital bones. She was neurologically intact with a nonmobile, tender, palpable mass over the left subocciptal area. A computed tomography (CT) scan showed a radiolucent, expansile, lytic lesion involving the left occipital bone. The patient underwent a left occipital craniectomy with resection of the bone and epidural mass. Permanent histopathologic sections and immunostains revealed a giant cell tumor. CONCLUSIONS: Giant cell tumors are generally benign, locally aggressive lesions for which surgical excision is the treatment of choice. This report contributes to the scarce literature on these tumors in the skull.

Adult↗
PubMed2004

Allelic loss of tumor suppressor genes in ameloblastic tumors.

Ameloblastoma is an odontogenic tumor with a variety of histologic appearances and an unpredictable biologic behavior. Little is known about allelic losses of tumor suppressor genes in ameloblastomas. This study surveyed DNA damage in ameloblastomas and correlated this with histologic sub-type and clinical outcome. There were 12 ameloblastomas (two peripheral, eight solid, and two unicystic) and three ameloblastic carcinoma studied for loss of heterozygosity of tumor suppressor genes on chromosomes 1p, 3p, 9p,10q, and 17p (L-myc, hOGG1, p16, pten, and p53). The frequency of allelic loss and the intratumoral heterogeneity were calculated. L-myc (71% frequency of allelic loss) and pten (62% frequency of allelic loss) had the most frequent allelic losses. Overall frequency of allelic loss and intratumoral heterogeneity were higher in mandibular and in unicystic tumors and lower in tumors that recurred/metastasized. The rate of allelic loss in the three carcinomas was similar to that seen in benign tumors. The frequency of allelic loss and intratumoral heterogeneity did not correlate with age, gender, histologic subtype, or prognosis. Since tumors that behaved aggressively did not harbor more allelic losses, it is likely that DNA damage in ameloblastomas and ameloblastic carcinomas is sporadic and cumulative. We conclude that other genetic or epigenetic mechanisms may be responsible for malignant behavior in ameloblastic carcinomas.

Adult↗
PubMed2004

Laryngeal paraganglioma: an updated critical review.

Laryngeal paragangliomas are rare submucosal lesions that arise from paraganglion cells located in the false vocal fold and subglottic larynx. To date, 76 recognized cases have been reported in the world literature. Symptoms arise when the lesions become large enough to impair function. Supraglottic paragangliomas cause hoarseness and deglutition disorders, whereas subglottic tumors become symptomatic when they obstruct the airway. Evaluation of these tumors includes obtaining a complete history. Familial paragangliomas and hypertension should be sought but are rarely, if ever, associated with laryngeal paragangliomas. MRI can detect these lesions and permit characterization of the vascularity of the lesion. Adding 111In pentetreotide scanning can distinguish neuroendocrine tumors from other submucosal laryngeal lesions, making the preoperative diagnosis clearer and obviating the need for biopsy. The biggest dilemma regarding laryngeal paragangliomas is making the correct pathologic distinction between paraganglioma, typical carcinoid, atypical carcinoid and medullary thyroid cancer. Immunohistochemical markers, supplementing standard histopathologic evaluation, can distinguish paragangliomas from the aforementioned tumors. This distinction is critical as the prognosis for treated paragangliomas is excellent compared to that for other neuroendocrine neoplasms. Almost all alleged malignant paragangliomas of the larynx are in reality atypical carcinoid tumors that have been misdiagnosed. Treatment should always comprise excision. Thyrotomy has the best chance of achieving a sustained cure without damaging phonation or deglutition. Laser excision has been used successfully but there is no great experience with this modality. Surgery is preferable to radiation for paragangliomas in all locations but especially so in the larynx, due to issues such as swelling, airway protection and destruction of cartilage. With increased clinical suspicion and the use of modern imaging techniques, laryngeal paragangliomas should be routinely diagnosed and treated without loss of laryngeal functions.

Age Distribution↗
PubMed2004

Osteoclast-type giant cell neoplasm of salivary gland. A microdissection-based comparative genotyping assay and literature review: extraskeletal "giant cell tumor of bone" or osteoclast-type giant cell "carcinoma"?

Primary salivary gland tumors resembling giant cell tumor of bone are very rare and have unsettled histogenesis. Both mesenchymal and epithelial origins have been suggested. We review 14 cases in the English-language literature and report another case, the first of which to be studied by microdissection-based microsatellite analysis. One-half of the tumors have been associated with a carcinoma, usually salivary duct carcinoma and carcinoma ex pleomorphic adenoma. Significant differences between this tumor and giant cell tumor of bone were observed. Unlike giant cell tumor of bone, in which the nuclei of the mononuclear and giant cells are similar, those of salivary gland show obvious differences between the nuclei of mononuclear cells and osteoclastic giant cells. In addition and in contrast to giant cell tumor of bone, the mononuclear cells of giant cell tumor of salivary gland express epithelial markers (epithelial membrane antigen, EMA; carcinoembryonic antigen, CEA) and androgen receptor. Genotypically, the microsatellite pattern of the giant cell component is more akin to the carcinomatous component and does not resemble giant cell tumor of bone. Biologically, giant cell tumor of salivary gland tends to be more aggressive than giant cell tumor of bone. We conclude that giant cell tumor of salivary gland is an unusual carcinoma that is not related to giant cell tumor of bone.

Alleles↗
PubMed2004

Molecular analysis to demonstrate that odontogenic keratocysts are neoplastic.

CONTEXT: Odontogenic keratocysts (OKCs) are unique odontogenic lesions that have the potential to behave aggressively, that can recur, and that can be associated with the nevoid basal cell carcinoma syndrome. Whether they are developmental or neoplastic continues to be debated. OBJECTIVES: To identify loss of heterozygosity of tumor suppressor genes in OKCs and to suggest a pathogenetic origin for these lesions. DESIGN: We examined 10 OKCs for loss of heterozygosity of tumor suppressor genes, using a microdissection and semiquantitative genotyping analysis. The genes analyzed included 10 common tumor suppressor genes, as well as the PTCH gene, which is mutated in nevoid basal cell carcinoma syndrome. RESULTS: Loss of heterozygosity was seen in 7 of 10 cases, with a frequency between 11% and 80% of the genes studied. The genes that exhibited the most frequent allelic losses were p16, p53, PTCH, and MCC (75%, 66%, 60%, and 60%, respectively). Daughter cysts were associated with a higher frequency of allelic loss (P =.02), but epithelial budding was not. CONCLUSIONS: Our study indicates that a significant number of OKCs show clonal loss of heterozygosity of common tumor suppressor genes. The finding of clonal deletion mutations of genomic DNA in these cysts supports the hypothesis that they are neoplastic rather than developmental in origin.

Adolescent↗
PubMed2003

Salivary duct carcinoma.

Salivary duct carcinoma (SDC) is a highly malignant tumor that is histologically similar to ductal carcinoma of the breast. This article presents the clinicopathologic features of 15 patients with SDC arising in the salivary glands. The majority of patients were male and aged 65 years or older. The tumor was most often located in the parotid gland. Pain, facial palsy, and presence of calcification in the CT scan were diagnostic features suggestive of SDC. Histologically, 27% of the tumors arose from pre-existing pleomorphic adenoma. Perineural and lymphatic invasion were common findings. There was an extensive cervical lymph node involvement (73%). Distant metastasis was the most common cause of failure. Although SDC exhibits an unpredictable clinical course, total parotidectomy with neck dissection and adjunctive radiation therapy appear to be appropriate for local and regional control of this aggressive neoplasm.

Adult↗
PubMed2002

Loss of heterozygosity mutations of tumor suppressor genes in cytologically atypical areas in chronic lymphocytic thyroiditis.

The relationship between chronic lymphocytic thyroiditis (CLT) and papillary thyroid carcinoma (PTC) is a subject of controversy. Some investigators suggest a causal relationship, whereas others regard the two as only a coincidental occurrence. An additional complicating factor is the presence of atypical nuclei frequently found within lymphoid infiltrates in CLT, which resemble those in PTC. The finding of the RET-PTC translocations in CLT has been reported by two independent groups of investigators, suggesting that the areas of nuclear atypia in CLT are neoplastic rather than reactive. In the present study, we report additional molecular findings that support the hypothesis that the atypical nuclear changes in CLT may be preneoplastic or neoplastic. We microdissected small areas with atypical nuclei in glands with CLT and observed loss-of-heterozygosity mutations of tumor suppressor genes. These genetic mutations are evidence of clonal preneoplastic or neoplastic changes in the follicular cells of CLT. The clinical malignant potential of these minute foci is likely to be very small but remains to be determined.

Carcinoma, Papillary↗
PubMedDate not supplied

Adenosquamous carcinoma of the upper aerodigestive tract: a clinicopathologic study of 12 cases and review of the literature.

PURPOSE: Adenosquamous carcinoma is an uncommon, controversial neoplasm. To further comprehend its natural history, the clinical and pathological features of 12 new cases were reviewed and analyzed collectively with those described in the English literature. MATERIALS AND METHODS: Twelve cases of adenosquamous carcinoma of the upper aerodigestive tract with adequate follow-up and available microscopic slides and paraffin tissue blocks were identified in the anatomic pathology files of Presbyterian Hospital of the University of Pittsburgh Medical Center over the period 1983-2001. RESULTS: The 8 men and 4 women ranged in age from 34 to 81 years (mean, 62.8 years). The larynx (5 cases) and the floor of the mouth (4 cases) were the most common sites of origin. Nine patients had cervical lymph nodes positive for carcinoma (8 at diagnosis), 7 experienced local recurrences, and 2 developed distant metastases. Four of 10 (40%) patients with follow-up died of disease. Combining our cases with those in the literature (total of 58 cases) revealed similar findings: 64.7% were associated with positive cervical lymph nodes, 46.7% experienced local recurrences, 23.1% developed distant metastases, and 42.9% died of their disease at a mean follow-up period of 24.7 months. CONCLUSIONS: Adenosquamous carcinoma is an aggressive neoplasm with a tendency for early lymph node metastasis, frequent local recurrence, occasional distant metastasis, and death from disease, usually within 2-3 years. Surgery with neck dissection is the treatment of choice.

Adult↗