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Biomedical subjects

Ashok R Shaha

Publications and source records attributed to Ashok R Shaha.

At least 55 records · Page 3Linked to original sources
PubMed2004

Follicular variant of papillary thyroid carcinoma: genome-wide appraisal of a controversial entity.

The majority of thyroid tumors are classified as papillary (papillary thyroid carcinomas; PTCs) or follicular neoplasms (follicular thyroid adenomas and carcinomas; FTA/FTC) based on nuclear features and the cellular growth pattern. However, classification of the follicular variant of papillary thyroid carcinoma (FVPTC) remains an issue of debate. These tumors contain a predominantly follicular growth pattern but display nuclear features and overall clinical behavior consistent with PTC. In this study, we used comparative genomic hybridization (CGH) to compare the global chromosomal aberrations in FVPTC to the PTC of classical variant (classical PTC) and FTA/FTC. In addition, we assessed the presence of peroxisome proliferator-activated receptor-gamma (PPARG) alteration, a genetic event specific to FTA/FTC, using Southern blot and immunohistochemistry analyses. In sharp contrast to the findings in classical PTC (4% of cases), CGH analysis demonstrated that both FVPTC (59% of cases) and FTA/FTC (36% of cases) were commonly characterized by aneuploidy (P = 0.0002). Moreover, the pattern of chromosomal aberrations (gains at chromosome arms 2q, 4q, 5q, 6q, 8q, and 13q and deletions at 1p, 9q, 16q, 17q, 19q, and 22q) in the follicular variant of PTC closely resembled that of FTA/FTC. Aberrations in PPARG were uniquely detected in FVPTC and FTA/FTC. Our findings suggest a stronger relationship between the FVPTC and FTA/FTC than previously appreciated and support further consideration of the current classification of thyroid neoplasms.

Adult↗
PubMed2004

Parapharyngeal lymph node metastasis: an unusual presentation of papillary thyroid carcinoma.

BACKGROUND: Parapharyngeal space nodal metastases are usually secondary to malignancies of the pharynx and sinonasal tract, although localization of lymphomas is also possible. Parapharyngeal metastases arising from thyroid papillary carcinoma are instead an exceedingly rare event, with only 10 cases reported up to now in the literature. METHODS: We describe two cases of parapharyngeal metastasis from thyroid papillary carcinoma in a man and a woman, aged 40 and 52 years, respectively. RESULTS: Both patients had a lesion that clinically appeared to be located in the parapharyngeal space; they underwent CT and MRI, which detected a cystic mass in the poststyloid compartment. In the first patient, fine-needle aspiration cytology failed in identifying the histologic nature of the lesion, which was excised through a transcervical approach. A diagnosis of metastatic thyroid papillary carcinoma was rendered and therefore the patient underwent total thyroidectomy. In the second patient, a total thyroidectomy, previously scheduled for multinodular goiter, was performed along with the removal of the parapharyngeal mass. Definitive histologic findings revealed that the two parapharyngeal masses were cystic metastases from a thyroid papillary carcinoma. Both patients received postoperative 131I treatment. Twenty-four months after surgery, the first patient is free of disease, whereas the second one has clear signs of abnormal 131I uptake in the lungs. CONCLUSIONS: The differential diagnosis of a parapharyngeal poststyloid mass should also include metastasis from thyroid papillary carcinoma. When the lesion displays a cystic appearance on imaging, it is advisable to rule out a thyroid primary by ultrasonographic examination. The occurrence of a metastasis in such unusual site, even though rarely reported, does not seem to significantly affect the prognosis of the disease.

Adult↗
PubMed2004

Paragangliomas of the head and neck.

Paragangliomas are neuroendocrine tumors derived from the extra-adrenal paraganglia of the autonomic nervous system. Within the head and neck, they are generally defined and named according to their site of origin, and may be found frequently neighboring vascular structures. Physiologic activity is rare in these neoplasms and they may exhibit patterns of inheritance which predispose their occurrence in families, often with multicentricity. These tumors generally exhibit a slow rate of growth, most often presenting asymptomatically as a space occupying mass lesion noted clinically or radiographically. The most common paraganglioma of the head and neck is the carotid body tumor followed by the jugulo-tympanic and vagal varieties. Other rare sites where this tumor may occur include; the larynx, sinonasal chambers and orbit. Diagnosis is generally made through a combination of clinical findings and radiographic studies. Magnetic resonance represents the most important imaging modality for the evaluation and characterization of suspected head and neck paraganglioma. Definitive management for these lesions should be carefully considered in relation to both tumor and patient-oriented factors, especially in regard to the potential morbidity of treatment. Surgery and radiation therapy represent the main treatment modalities for paraganglioma. The selection of treatment depends on the size, location, and biologic activity of the tumor as well as the overall fitness of the patient. Although radiotherapy may be effective in arresting growth of these tumors, rarely is the neoplasm eliminated without surgical resection. Surgery may be associated with significant morbidity, primarily as a consequence of incurring major cranial nerve injury. Patient selection (relative to age and medical condition) should be carefully considered prior to recommending aggressive surgery for paragangliomas of head and neck, especially in those patients at risk for disabling surgical morbidity.

Carotid Body Tumor↗
PubMed2004

Parathyroid re-exploration.

Re-operative parathyroid surgery is always a challenge for the endocrine surgeon. This article discusses the issues the parathyroid surgeon must consider before and during re-operative surgery,with special attention to recently introduced adjunctive techniques.

Humans↗
PubMed2004

Management of malignant sublingual salivary gland tumors.

The majority of tumors of the sublingual gland are malignant, with adenoid cystic carcinoma and mucoepidermoid carcinoma being the most frequent. Many other malignant tumor types have also been reported. The sublingual gland anatomically is not a unit organ and while it is described anatomically as being confined to the anterior floor of the mouth, salivary tissue may be located laterally along the submandibular duct and posterior floor of the mouth. Diagnosis should be suspected when any thickening or raised lesion presents in this area and a biopsy performed to confirm malignancy before planning further treatment. Surgery is the treatment of choice, and should include an en-block resection of the anterior floor of mouth as a minimum, and may include a portion of mandible, as well as a supraomohyoid neck dissection. Adjuvant radiotherapy should be considered in most of the patients after surgical excision.

Carcinoma, Adenoid Cystic↗
PubMed2004

Implications of prognostic factors and risk groups in the management of differentiated thyroid cancer.

OBJECTIVES/HYPOTHESIS: The outcome in differentiated thyroid cancer generally depends on the stage of the disease at the time of presentation; prognostic factors such as age, grade, size, extension, or distant metastasis; and risk groups (eg, low or high risk). The author has reviewed a large number of patients with differentiated thyroid cancer to analyze their hypothesis and to confirm that various risk groups have a major implication in relation to extent of the treatment and outcome. Differentiated thyroid cancers make up 90% of all thyroid tumors. The prognostic factors are well defined, such as age, size of the tumor, extrathyroidal extension, presence of distant metastasis, histological appearance, and grade of the tumor. The author has previously divided the risk groups into low-, intermediate-, and high-risk categories based on prognostic factors. The study describes the author's treatment approach related to the extent of thyroidectomy and adjuvant therapy based on various risk groups and the long-term survival. STUDY DESIGN: Retrospective. METHODS: In a retrospective review of 1038 patients with differentiated thyroid carcinoma, various prognostic factors were studied by univariate and multivariate analysis. The significant prognostic factors were studied in detail and, based on these prognostic factors, the patients were divided into low-, intermediate- and high-risk groups. The survival curves were plotted by Kaplan-Meier method. RESULTS: The long-term survivals in low-, intermediate- and high-risk groups were 99%, 87%, and 57% respectively. Based on these risk groups, a decision tree was made regarding extent of thyroidectomy and adjuvant treatment. In the high-risk group and selected patients in the intermediate-risk group, aggressive surgery including removal of all gross disease and extrathyroidal extension with postoperative radioactive iodine ablation is recommended. In the low-risk group and selected patients in the intermediate-risk group, lobectomy appears to be satisfactory with excellent long-term outcome. The surgical treatment offers the best long-term results in low-risk patients, and the role of adjuvant treatment in this group is questionable. CONCLUSION: The decisions in the management of well-differentiated thyroid cancer should be based on various prognostic factors and risk groups. The long-term survival in the low-risk group is excellent, and consideration should be given to conservative surgical resection depending on the extent of the disease. In the high-risk group and selected patients in the intermediate-risk group, total thyroidectomy with radioactive ablation is warranted. A consideration may be given to external-beam radiation therapy in selected high-risk patients. It is apparent, based on the author's clinical experience and critical retrospective analysis, that the author's hypothesis that risk groups are extremely important in the long-term outcome of patients with differentiated thyroid cancer is correct. Based on various risk groups, the author currently is able to guide the treatment policies for thyroid cancer.

Adult↗
PubMed2003

Current management of mucosal melanoma of the head and neck.

While mucosal-based melanomas of the head and neck region are uncommon lesions, when they do arise they usually follow an inexorably aggressive course. Experience with these tumors is, necessarily, limited; as such, well-worked out treatment protocols for the treatment of such lesions are in short supply. It appears as though mucosal melanomas (MuMs) develop more frequently in the nasal cavity and paranasal sinus region, and less often in the oral cavity. It seems that the incidence of nodal metastasis is significantly lower for sinonasal MuMs than it is for MuMs of the oral cavity; this observation may influence decisions about performing neck dissection as a function of location of the primary MuM. At present, surgical excision remains the mainstay of treatment; however, anatomical complexities within the region can hamper attempts at complete excision. Radiotherapy has not traditionally been relied on for routine treatment of MuM, although some recent reports have challenged this view. Chemotherapy is, at present, employed principally in the treatment of disseminated disease and for palliation. As a diagnostic matter, MuM belongs to the class of tumors that, on light microscopy, may with some regularity be confused with other malignancies (including sarcomas, plasmacytomas, and carcinomas); as a consequence, this is a diagnosis which is often best confirmed by way of ancillary testing via immunohistochemical studies. A better grasp of the best means of treating MuM will likely come only when large referral centers are able to pool their experiences with these uncommon yet virulent malignancies.

Head and Neck Neoplasms↗
PubMed2003

Prognostic indicators of outcomes in patients with distant metastases from differentiated thyroid carcinoma.

BACKGROUND: Distant metastasis is uncommon in differentiated thyroid cancer and the prognosis is unclear. This study aims to evaluate outcomes and to define independent variables that are associated with tumor-related mortality in patients with distant metastasis from thyroid carcinoma. STUDY DESIGN: A retrospective review of the thyroid cancer research database identified 336 patients with distant metastasis from differentiated thyroid carcinoma treated at a single institution between 1941 and 2000. After excluding patients with local or regional recurrence, distant disease was either the first site of recurrence or was detected at the time of diagnosis of the primary tumor in 242 patients (72%). Patient, tumor, and treatment-related factors were analyzed for their relation to disease-specific survival (DSS) using multivariate Cox regression and the log-rank test. RESULTS: Median survival was 4.1 years and 10-year DSS was 26%. Distant disease was synchronous with the primary diagnosis in 97 of 242 (40%) patients. The site of metastasis was lung only in 103 (43%) patients, bone only in 80 (33%), other sites in 14 (6%), and more than one organ system in 45 (19%). Multivariate analysis identified age 45 years or more, symptoms, site other than lung only or bone only, and no radioactive iodine treatment for the metastasis as predictors of poor outcome with 13%, 11%, 16%, and 12% 10-year DSS, respectively. This compares with age less than 45 years, asymptomatic presentation, metastasis only in the lung or bone, and radioactive iodine treatment with 10-year DSS rates of 58%, 45%, 32%, and 33%, respectively (all p < 0.0001). Radioactive iodine treatment was more often given in patients who were less than 45 years of age, asymptomatic, and with metastasis only in the lung or bone only (p = 0.03, 0.11, 0.01). CONCLUSIONS: Longterm survival is possible in patients with distant metastasis from differentiated thyroid cancer. This retrospective study found that age of 45 years or more, site other than lung only or bone only, and symptoms at the time of diagnosis are associated with poorer outcomes.

Adenocarcinoma, Follicular↗
PubMed2003

Management of sarcomas of the head and neck in adults.

Sarcomas account for less than 1% of all malignant neoplasms occurring in the head and neck in adults. These tumors exhibit variable growth and degrees of aggressiveness which are primarily dependent on histologic grade. The pattern of growth demonstrated by sarcomas is generally by local advancement with high-grade tumor exhibiting extensive involvement of adjacent visceral and neurovascular structures. Regional metastasis is uncommon. Etiologic considerations include the tumorigenic effects of prior external beam radiotherapy and the development of second malignancies in the form of sarcomas. The clinical presentation of these neoplasms is variable and dependent on subsite of involvement as well as the aggressiveness of tumor growth. Histologic diagnosis is frequently challenging, often requiring the aid of immunohistochemical staining techniques. Treatment is predominantly surgical, utilizing wide local excision where en-bloc resection is feasible. Radiotherapy, by means of external beam or implant, plays an important adjunctive role in management, especially for tumors where en-bloc resection with margin control is not possible. Chemotherapy regimens are available for soft tissue neoplasms and osteosarcoma and are primarily designed to improve local control. Survival is predicted on the incidence of local recurrence and risk of distant metastasis, both of which are influenced by tumor grade. Low-grade tumors exhibit improved survival over that of less differentiated tumors.

Head and Neck Neoplasms↗
PubMed2003

Current philosophy on the management of cancer of the base of the tongue.

Cancer of the base of the tongue is a challenging disease for the head and neck surgeon, radiation oncologist and medical oncologist. However, over the last 10-15 years, improved treatment strategies have evolved which offer patients high probability of loco-regional control, survival, and good quality of life. The ability to offer patients good oncologic and functional outcomes serves as a paradigm for the successful application of multidisciplinary care, and the emphasis on quality of life in head and neck cancer treatment. This review provides an overview of the treatment options that exist, their advantages and disadvantages, and hopefully provides proper guidelines for the current management of this challenging disease.

Combined Modality Therapy↗
PubMed2003

Current management of tonsillar cancer.

Traditionally, risk factors for the development of tonsil cancer include the use of alcohol and/or tobacco, however a significant proportion of new cases develop in young patients without these risk factors. Recent investigation suggests that human papilloma virus (HPV) may serve as an etiology in such cases and represent a unique risk factor in a sub-set of patients. Irrespective of the etiology, in the majority of cases early carcinoma of the tonsil can effectively be treated using single modality therapy. While local-regional control and survival are similar following surgery or radiotherapy, primary surgery can be accomplished with minimal functional morbidity while reserving radiation for recurrent disease. In contrast, surgical salvage following external beam radiotherapy can be technically challenging and is often associated with a significant increase in surgical complications and functional morbidity. In contrast to early tonsillar disease, advanced tonsil cancer represents a clinical challenge that requires multimodality therapy. While advanced lesions are often treated with a combination of radiation, chemotherapy, and surgical ablation, management of the neck and distant metastases continues to present a therapeutic dilemma.

Carcinoma↗
PubMed2003

Sentinel lymph node biopsy in head and neck cancer.

In the past decade, the technique of sentinel lymph node biopsy (SLNB) has been applied to a vast array of primary neoplasms, ranging from head and neck melanoma to vulvar carcinoma. At present, experience with SLNB is greatest in patients with melanoma and breast cancer. In view of the well known complications associated with cervical node dissection, it has been suspected for some time that cervical SLNB, if successful, might reduce the morbidity associated with the definitive care of patients with head and neck cancers. This report assesses the current status of SLNB in the treatment of head and neck cancers; while formal investigations of the efficacy of this technique are recommended, SLNB has not yet been demonstrated to possess the same level of utility seen in SLNB in melanoma and breast cancer patients. As a consequence, the application of SLNB to head and neck cancers remains an experimental technique--one which has not yet acquired the status of the standard of patient care.

Carcinoma, Squamous Cell↗
PubMed2003

Management of cancer of the retromolar trigone.

Treatment of cancer of the retromolar trigone (RMT) is controversial. While early lesions may be managed with single-modality, more advanced lesions may invade the mandible, pterygoid musculature, and the adjacent mucosa of the tonsillar pillar and soft palate, therefore making therapeutic decisions more complicated. Treatment options traditionally include surgical resection, external beam irradiation, and combined modality therapy. The choice of therapy is dependent on the extent of the tumor, nodal metastasis, and the medical status of the patient and comorbid conditions. The following review outlines the current issues relevant to the diagnosis and therapy of patients with RMT malignancy.

Humans↗