Case report: Lymph node metastasis of pelvic alveolar rhabdomyosarcoma diagnosed by fine needle aspiration cytology.

Rhabdomyosarcoma (RMS) is a common soft tissue malignant tumor, especially in young patients. Alveolar rhabdomyosarcoma (ARMS) is a subtype of RMS that is prevalent in adolescents. This malignant tumor usually develops in the extremities and can also involve the trunk, perineum, and pelvis. Now, we report a rare case of pelvic lymph node metastatic alveolar RMS in a young patient, which was determined by fine needle aspiration cytology (FNAC). To the best of our knowledge, this is the first case in which the definite diagnosis of ARMS was initially made by FNAC.

Autoimmune thyroiditis a fibrous variant of Hashimoto's thyroiditis: A rare case.

Hashimoto thyroiditis (HT) is an autoimmune disorder characterized by inadequate thyroid hormone production. A fibrous variant is one of the rarest entities of Hashimoto's thyroiditis disease. A 42 -year-old female patient presented to our service with neck swelling associated with difficulty swallowing; she was discovered to have an enlarged thyroid gland with mass effect. She underwent an ultrasound and fine-needle aspiration (FNA), which was consistent with Hashimoto's thyroiditis -Bethesda category II-. Due to compressive symptoms, we proceeded to total thyroidectomy. The final histopathology revealed numerous polymorphic lymphoid cells, plasma cells, follicular cells, and scattered Hürthle cells, characteristic of fibrous variants. The surgery was complicated with voice hoarseness and hypocalcemia, which was managed successfully with corticosteroids and calcium supplements. The mainline treatment of HT is medical, but surgical intervention can be considered in some cases. A multidisciplinary approach is needed for successful management. Continuous patient monitoring post-operatively is vital to detect and intervene with early surgical complications.

A Bibliometric Analysis of 8271 Publications on Thyroid Nodules From 2000 to 2021.

Introduction: Thyroid nodules (TNs) are a common clinical condition. The probability of thyroid nodules being malignant is 7-15%. However, in recent decades, a number of publications on TNs have not been well summarized and discussed. The aim of this study was to summarize and sort out medical publications on TNs over the past 2 decades using a bibliometric method. Materials and Methods: Medical publications from January 1st, 2000, to November 1st, 2021, were searched in the Web of Science Core Collection database using the Medical Subject Heading (MeSH) term "thyroid nodule". Full associated data were downloaded, and detailed information was extracted using the bibliometric analysis platform VOSviewer. Results: A total of 8271 publications related to TNs from the last 2 decades were found and included in this study. An increasing trend was presented in the annual number of publications. The United States, China and Italy contributed the most publications. Carcinoma, management, ultrasound, and fine-needle aspiration were the most popular subjects in the field of TNs. The topics of the studies could be stratified into four clusters. The first cluster was using ultrasound to evaluate the nodules, including the thyroid imaging reporting and data system (TI-RADS), elastography and benign features. The second cluster was the fine-needle aspiration method, including the Bethesda system, cytology and BRAF mutations. The third cluster was the management of nodules, including radiofrequency and thermal ablation, surgery, and consensus statements. The last cluster was carcinoma, which is correlated with all three clusters described above. The preoperative diagnosis of cytologically indeterminate nodules was particularly highlighted in the top 10 most cited publications in recent years. Conclusion: How to diagnose thyroid nodules as malignant or benign, especially in cytologically indeterminate nodules, is still the most concerning topic in TN research. Although the fine-needle aspiration method and gene-expression classifiers show promising results, there is still a crucial need for translations from fundamental studies to clinical applications.

Assessing immunological and virological responses in the liver: Implications for the cure of chronic hepatitis B virus infection.

Cure from chronic HBV infection is rare with current therapies. Basic research has helped to fundamentally improve our knowledge of the viral life cycle and virus-host interactions, and provided the basis for several novel drug classes that are currently being developed or are being tested in clinical trials. While these novel compounds targeting the viral life cycle or antiviral immune responses hold great promise, we are still lacking a comprehensive understanding of the immunological and virological processes that occur at the site of infection, the liver. At the International Liver Congress 2021 (ILC 2021), a research think tank on chronic HBV infection focused on mechanisms within the liver that facilitate persistent infection and looked at the research questions that need to be addressed to fill knowledge gaps and identify novel therapeutic strategies. Herein, we summarise the discussion by the think tank and identify the key basic research questions that must be addressed in order to develop more effective strategies for the functional cure of HBV infection.

An extensive surgical resection in stage T4 small cell lung cancer with cardiac invasion: A case report and literature review.

Introduction and importance: We report a rare case of a patient with a mass involving both the hilum and the heart, but its specific nature could not be determined. SCLC was confirmed by postoperative pathology. It revealed that radical surgical resection for T4 SCLC should be considered an important part of multimodality treatment. Case presentation: A 49-year-old gentleman complained of mild chest tightness for a week. Two large mass lesions were detected on CECT in the left atrium and left hilum. After an MDT discussion, an extended resection was recommended. Postoperative pathology denoted a complete excision with no residuals and negative lymph nodes. Clinical discussion: Due to the rarity of lung metastases to the heart, it is vital to determine the homology between the hilar mass and the cardiac mass. Based on this, simultaneous surgical treatment is done and it is very beneficial for patients by eliminating those hazards, such as acute mechanical cardiac obstruction, and cardiac embolism. Our literature review demonstrates that the SCLC tumour progresses rapidly after cardiac metastasis, limiting the chance of a complete resection. Furthermore, complete resection of T4 tumours in NSCLC has been attempted many times, so it should also be tried on SCLC. Conclusion: It is common for SCLC tumours to progress rapidly once they havemetastasized to the heart. An aggressive operation such as radical resection can reduce tumor burdens, minimize the risk of sudden acute death and improve patient follow-up treatment, all of which may prolong the survival of patients.

When Should You Trust Your Doctor? Establishing a Theoretical Model to Evaluate the Value of Second Opinion Visits.

In order to produce a mathematical model for better understanding of the benefits and utilization of second opinions and to understand the contradiction between the value of second opinions and their perceived underuse, we developed an expected utility theory model to quantify their value. We use a case-based example to find types of biases that could affect second opinions. Although the baseline expected utility theory model presented assumes providers are rational, we relax this and discuss the implications for how these alternative specifications alter predicted use. We found that second opinions are valuable when diagnostic accuracy is variable across physicians or access to high-quality care is restricted. In a stylized simulation example in which about half (50.1%) of diagnoses were incorrect, receipt of 1 second opinion reduced the error rate to 25.8% and receipt of 2 second opinions reduced the error rate to 16.0%. After incorporating potential biases into the model, the value of second opinions increases only when aversion to changing the initial diagnosis is greater than aversion to correcting a mistake. Additionally, this model reveals that second opinions have value even when diagnostic accuracy is perfect. Further, when financial incentives differ from the incentives of the initial consult, a second opinion offers patients a reasonable bound of their treatment options. To conclude, we identify numerous reasons for underuse of second opinions. Specifically, value depends on the degree of diagnostic uncertainty, presence of behavioral biases, and variation in local compensation regimes. Despite their value, recent trends could actually decrease the value of second opinions.

Diagnostic Performance of FDG-PET/CT Scan as Compared to US-Guided FNA in Prediction of Axillary Lymph Node Involvement in Breast Cancer Patients.

PURPOSE: The aim of this study was to evaluate the diagnostic ability of 2-deoxy-2-[fluorine-18]fluoro-d-glucose (18F-FDG) PET/non-contrast CT compared with those of ultrasound (US)-guided fine needle aspiration (FNA) for axillary lymph node (ALN) staging in breast cancer patients. PATIENTS AND METHODS: Preoperative 18F-FDG PET/non-contrast CT was performed in 268 women with breast cancer, as well as ALN dissection or sentinel lymph node (SLN) biopsy. One hundred sixty-four patients underwent US-guided FNA in combination with 18F-FDG PET/CT. The diagnostic performance of each modality was evaluated using histopathologic assessments as the reference standard. The receiver operating characteristic (ROC) curves were compared to evaluate the diagnostic ability of several imaging modalities. RESULTS: Axillary 18F-FDG uptake was positive in 180 patients, and 125 patients had axillary metastases according to the final pathology obtained by ALN dissection and/or SLN dissection. Of the patients with positive 18F-FDG uptake in the axilla, 21% had false-positive results, whereas 79% were truly positive. Eighty-eight patients had negative 18F-FDG uptake in the axilla, among which 25% were false-negative. 18F-FDG-PET/CT had a sensitivity of 86.59% and a specificity of 63.46% in the assessment of ALN metastasis; on the other hand, US-guided FNA had a sensitivity of 91.67% and a specificity of 87.50%. The mean primary cancer size (p = 0.04) and tumor grade (p = 0.04) in combination were the only factors associated with the accuracy of 18F-FDG PET/CT for detecting metastatic ALNs. CONCLUSION: The diagnostic performance of 18F-FDG PET/CT for the detection of axillary node metastasis in breast cancer patients was not significantly different from that of US-guided FNA. Combining 18F-FDG PET/CT with US-guided FNA or SLN biopsy could improve the diagnostic performance compared to 18F-FDG PET/CT alone.

Ectopic ACTH Production Caused by Metastatic Parotid Gland Acinic Cell Carcinoma.

OBJECTIVE: To present a case of adrenocorticotropic hormone (ACTH) hypersecretion caused by a metastatic acinic cell carcinoma (AcCC) of the parotid. Only 6 cases have been reported prior to October 2019. We believe that this condition is under-reported and hope that improved recognition will improve its reporting. METHODS: Diagnosis in this case was done using surgical pathology of the primary tumor, involving lymph nodes, and a metastatic lesion. Following an initial misdiagnosis, a final diagnosis of AcCC was made using immunohistochemical staining. ACTH hypersecretion was diagnosed by testing for random ACTH, cortisol, and 24-hour urine aldosterone and cortisol levels. RESULTS: A 57-year-old man presented with hypokalemia, lower-extremity edema, and left-side rib pain 7 months following excision of a 4-cm left-parotid tumor. Immunostaining positive for DOG-1, CK7, pan-cytokeratin (including CAM5.2), and SOX10 led to the diagnosis of AcCC. ACTH hypersecretion was diagnosed based on a random ACTH level of 307 pg/mL (normal morning value, 7.2-63 pg/mL), a cortisol level of 33 µg/dL (normal morning value, 4.3-19.8 µg/dL; normal PM value, 3.1-15.0 µg/dL), a 24-hour urine aldosterone level of <0.7 U (normal, 2.0-20 U), and a 24-hour urine cortisol level of 4564 U (normal, 3.5-45 U). The patient's ACTH hypersecretion and hypokalemia were treated with potassium replacement, amiloride, and ketoconazole. His metastatic recurrence was treated with radiotherapy, chemotherapy, and immunotherapy. The patient died after being diagnosed with sepsis secondary to multifocal postobstructive pneumonia 4 months after the diagnosis of his metastatic recurrence. CONCLUSION: Ectopic ACTH production caused by metastatic AcCC is a rare phenomenon but has been increasingly described over the last 15 years. We believe that this condition likely has a greater prevalence than what is reported and that improved recognition will lead to improved outcomes.

Painful Subacute Thyroiditis is Commonly Misdiagnosed as Suspicious Thyroid Nodular Disease.

OBJECTIVE: To investigate and characterize the clinical and radiologic features of 10 patients with painful subacute thyroiditis with ultrasound findings considered suspicious for malignancy or for whom biopsy of a suspicious area was recommended by an attending radiologist. PATIENTS AND METHODS: Ten patients with painful subacute thyroiditis were seen from June 1, 2016, through January 1, 2019. All 10 patients presented to an endocrine or thyroid clinic with a neck ultrasound report stating findings suspicious for malignancy or nodular disease. Clinical, laboratory, radiographic, and pathologic data were (retrospectively collected and) reviewed. RESULTS: The mean ± SD patient age was 49.0±15.0 years at diagnosis; 8 patients were female. All the patients presented with a low or undetectable serum thyrotropin level. Six of 7 patients with available inflammatory markers had elevated levels. Thyrotropin receptor antibodies were absent in all 6 patients tested. On follow-up imaging, 8 patients had complete resolution or improvement of described findings, 1 was lost to follow-up, and 1 had an incidental nodule that was biopsied after the episode of thyroiditis and found to be papillary thyroid carcinoma. CONCLUSION: Painful subacute thyroiditis demonstrates specific sonographic patterns that may be misdiagnosed as suspicious thyroid nodular disease. Recognition of the innocent and transient nature of these findings is important for the proper management and monitoring of these patients.

Diagnosing Biliary Strictures: Distinguishing IgG4-Related Sclerosing Cholangitis From Cholangiocarcinoma and Primary Sclerosing Cholangitis.

Biliary strictures caused by inflammation or fibrosis lead to jaundice and cholangitis which often make it difficult to distinguish malignant strictures. In cases when malignancy cannot be excluded, surgery is often performed. The concept of immunoglobulin G4 (IgG4)-related sclerosing cholangitis (SC) as a benign biliary stricture was recently proposed. The high prevalence of the disease in Asian countries has resulted in multiple diagnostic and treatment guidelines; however, there is need to formulate a standardized diagnostic strategy among various countries considering the utility, invasiveness, and cost-effectiveness. We evaluated accuracies of various diagnostic modalities for biliary strictures comparing pathology in the Delphi meetings which were held in Rochester, MN. The diagnostic utility for each modality was graded according to the experts, including gastroenterologists, endoscopists, radiologists, and pathologists from the United States and Japan. Diagnostic utility of 10 modalities, including serum IgG4 level, noninvasive imaging, endoscopic ultrasound, endoscopic retrograde cholangiopancreatography-related diagnostic procedures were advocated and the reasons were specified. Serum IgG4 level, noninvasive imaging, diagnostic endoscopic ultrasound and intraductal ultrasonography under endoscopic retrograde cholangiopancreatography were recognized as useful modalities for the diagnosis. The information in this article will aid in the diagnosis of biliary strictures particularly for distinguishing IgG4-SC from cholangiocarcinoma and/or primary SC.

To Be or Not To Be: A Case of Recurrent Swelling Syndrome of Thoracic Duct.

Thoracic duct aneurysm is a rare entity presenting as a stable, asymptomatic, left supraclavicular swelling. We report an unusual case of a thoracic duct aneurysm in a 71-year-old woman presenting as a recurrent swelling syndrome of the left supraclavicular area associated with sporadic episodes of sharp left subcostal pain. (Level of Difficulty: Intermediate.).

Osteoclastic giant cell tumor of the pancreas with synchronous jejunal gastrointestinal stromal tumor: A case report.

Osteoclastic giant cell tumor of the pancreas is a rare aggressive tumor, counting for 2-7% of all pancreatic cancers. Surgery is considered the most appropriate treatment. We report a case of a 84-year-old man with incidentally detected 11cm tumor in the pancreatic tail and another 6 cm tumor located in the jejunum on abdominal computed tomography. The patient underwent distal pancreatectomy with splenectomy along with segmental resection of the tumor bearing part of the jejunum. On histological examination, osteoclast-like giant cells with some areas of metaplastic bone were observed which confirmed the diagnosis of osteoclastic tumor of the pancreas. The jejunal tumor was strongly c-kit positive on immunohistochemistry which confirmed the diagnosis of GIST. On the last follow up at 2 years after surgery, there is no evidence of recurrence or distant metastasis. Pancreatic OGCT has a better prognosis after resection than pancreatic adenocarcinoma. Its co-existence jejunal GIST, as seen in the index case, has not been reported in the English literature till date.

Differentiating benign from malignant pancreatic cysts on computed tomography.

PURPOSE: It is important to identify features on computed tomography (CT) that can distinguish between benign and premalignant or malignant pancreatic cysts to avoid unnecessary surgeries. This study investigated the preoperative diagnostic evaluation of cystic pancreatic lesions to determine how advanced imaging and clinical factors should guide management. METHODS: In total, 53 patients with 27 benign and 26 premalignant or malignant cysts were enrolled. CT features of the cysts were compared using univariate and multivariate analyses. RESULTS: On univariate analysis, a solid component (p < 0.01), septation (p < 0.01), location (p < 0.01), border (p < 0.01), wall enhancement (p = 0.01), lesion margins (p < 0.01), pancreatic atrophy (p = 0.04), and a cystic wall (p < 0.01) were all significantly different between benign and premalignant or malignant cysts. On multivariate analysis, only a solid component (p < 0.01) and septation (p < 0.01) were significant. CONCLUSION: A thin cystic wall, uniform homogeneity, a clear border, the presence of septation, pancreatic atrophy, and the absence of both wall enhancements and solid components were more frequently seen in benign cysts. A thick wall, lack of homogeneity, the presence of wall enhancements and solid components, absence of septation, only a small degree of pancreatic atrophy, and unclear borders were more frequent among premalignant or malignant cysts. The only CT features to differentiate benign from premalignant or malignant cysts were a solid component and septation.

Feasibility of ultrafast dynamic magnetic resonance imaging for the diagnosis of axillary lymph node metastasis: A case report.

A 74 year old Japanese woman was diagnosed with invasive breast carcinoma. Her axillary lymph node was slightly swollen and had a short-axis diameter of 8 mm, but fine-needle aspiration did not lead to the diagnosis of metastasis. Subsequent 18F-fluorodeoxyglucose positron emission tomography/computed tomography showed no abnormal accumulation on the lymph node. Ultrafast dynamic magnetic resonance imaging yielded a very fast contrast enhancement like that of the primary lesion based on which we suspected lymph node metastasis. To our knowledge, this is the first report that shows that ultrafast imaging has contributed to the diagnosis of axillary lymph node metastasis.

Limb-salvage surgery offers better five-year survival rate than amputation in patients with limb osteosarcoma treated with neoadjuvant chemotherapy. A systematic review and meta-analysis.

BACKGROUND: Osteosarcoma is the most common primary bone sarcoma. Currently, the main treatment option for high-grade osteosarcomas is neoadjuvant chemotherapy, followed by surgical resection of the lesion and adjuvant chemotherapy. Limb salvage surgery (LSS) and amputation are the main surgical techniques; however, controversy still exists concerning the best surgical method. Our meta-analysis compared the effectiveness of LSS and amputation combined with neoadjuvant chemotherapy in patients with limb osteosarcoma, in terms of 5-year overall survival (OS), 5-year disease-free survival (DFS) and local recurrence rate. METHODS: Following the established methodology of PRISMA guidelines, a literature search was conducted in PubMed, Cochrane, Google Scholar from 1975 until January 2020. Two independent reviewers evaluated the study quality based on the Newcastle-Ottawa scale. Odds ratio and 95% confidence interval of the OS, DFS and local recurrence rate were calculated. RESULTS: Thirteen studies were finally included with a total of 2884 patients; 1986 patients undergone LSS and 898 amputations. Five-year overall survival was almost 2-fold in patients treated with LSS than those treated with amputation (OR: 1.99; 95% CI: 1.35-2.93; I2 = 74%, p < 0.001). No difference was found in 5-year DFS between LSS patients and amputees (OR: 1.24; 95% CI: 0.55-2.79; I2 = 67%, p = 0.01). The odds of local recurrence was numerically higher in LSS compared to amputation but not statistically significant (OR: 2.29; 95% CI: 0.95-5.53; I2 = 47%, p = 0.05). However, the included studies did not clearly define differences in the stages of patients of the two groups. CONCLUSION: Our study demonstrated that in patients with limb osteosarcoma treated with neoadjuvant chemotherapy, LSS is associated with a higher 5-year overall survival and the odds of local recurrence may be increased but these results should be interpreted with caution due to high heterogeneity.

Fusion Image-Guided and Ultrasound-Guided Fine Needle Aspiration in Patients With Suspected Hepatic Metastases.

AIM: The aim of this study was to compare the diagnostic adequacy of computed tomography (CT)-ultrasound (US) fusion image-guided fine needle aspiration (FNA) and US-guided FNA in patients with suspected hepatic metastases. METHODS: Thirty consecutive patients of either sex with known or unknown primary malignancy suspected of having liver metastases on both US and CT, whose multiphasic contrast-enhanced computed tomography was performed using a 64-slice or a higher slice CT scanner, and who were referred for percutaneous FNA were included in this prospective study approved by the institutional review board of the study institute. CT-ultrasound fusion image-guided FNA of the largest lesion using electromagnetic tracking and with freehand ultrasound-guided FNA were performed in the same sitting. Value of fitness, which is a rough estimate of how well the fusion has been achieved, was recorded. Diagnostic adequacy of smears was assessed by a scoring system based on cellular material, background blood/clot, degree of cellular degeneration or trauma, and retention of architecture. RESULTS: The size of the lesions ranged from 1 to 10 cm, and the depth of location of the lesions ranged from 1.4 to 9.3 cm. The fusion fitness values ranged from 1.2 to 10 mm. The scores of the smears did not correlate with lesion size, depth of location, and fusion fitness value. Diagnostic adequacy was seen in 90% and 93.3% of lesions sampled by fusion image guidance and ultrasound guidance, respectively (p = 0.655). All the lesions that yielded inadequate smears by fusion guidance were deep-seated lesions (>5 cm). All the lesions that yielded inadequate smears by ultrasound guidance were small lesions (<3 cm). No complications were encountered in any of the patients. CONCLUSION: Fusion image-guided FNA is a safe procedure with a high diagnostic adequacy rate. Fusion image-guided FNA is not better than US-guided FNA for conspicuous hepatic lesions; however, it may be useful in inconspicuous lesions.

Lymphatic malformation of the masseter: A case report.

Intramuscular vascular malformations are rare tumours occurring in less than 1% of skeletal muscles throughout the body, about 15% arising in the head and neck. Of these, lymphatic malformations are encountered to a lesser extent, being common in the tongue and the masseter being very rare. We present a case report of a lymphatic malformation of the masseter muscle in a 27 year old male. He presented with a swelling on his right cheek that had developed 1 year ago. Fine needle aspiration (FNA) of the lesion and Computed Tomography (CT) scans were done following which the provisional diagnosis of lymphatic malformation in the masseter was made. Surgical excision of the lesion was performed subsequently and histopathological examination confirmed the diagnosis. It is very rare to find a lymphatic malformation in the masseter and with such late presentation. Follow up should be done to note for potential recurrence.

Endoscopic Ultrasound (EUS) Guided Fine Needle Aspiration: A New Modality to Diagnose Peritoneal Tuberculosis in Presence of Decompensated Cirrhosis-A Case Series and Review of Literature.

BACKGROUND: The gold-standard for diagnosis is growth of Mycobacterium tuberculosis on ascitic fluid or peritoneal culture. Due to the non-specific signs and symptoms of disease, its early diagnosis is difficult, especially in patients with decompensated cirrhosis. The reported sensitivity of ascitic fluid is low and to obtain tissue for peritoneal biopsy in patients with cirrhosis is difficult. Endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) is a good alternative to obtain peritoneal tissue for establishing the diagnosis of peritoneal TB. OBJECTIVE: To assess the role of EUS-FNA in the diagnosis of peritoneal tuberculosis in patients with decompensated cirrhosis. METHODS: Consecutive patients with peritoneal thickening, ascites and decompensated cirrhosis underwent EUS-FNA from the thickened omentum. Presence of granuloma or demonstration of acid fast bacilli was diagnostic of peritoneal tuberculosis. RESULTS: A total of 5 patients with CLD underwent EUS-FNA from omentum. FNA cytology revealed granuloma with multinucleated cells in all patients (100%) and AFB stain was positive in 2 of them (40%). CONCLUSION: We hereby report the use of EUS guided fine needle aspiration (FNA) of peritoneum as a newer, safe and unexplored technique for diagnosis of peritoneal TB.

Rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology.

Thyroid cancer is the most common malignancy of the endocrine system and includes well-differentiated forms, namely papillary and follicular carcinomas, and the poorly differentiated and undifferentiated forms that result from the transformation of thyroid follicular cells (anaplastic carcinomas). Notably, 5-10% of all thyroid cancers are medullary thyroid cancers that arise from parafollicular cells also known as C cells. The most common genetic mutations in papillary and follicular thyroid cancers are point mutations of the BRAF or RAS genes, while the most common chromosomal alterations are RET/PTC and PAX8/PPARγ rearrangements. The most frequent initial manifestation of thyroid cancer is the appearance of a nodule most of which are benign; indeed, less than 5% are malignant. However, some cases are misdiagnosed, and many patients undergo unnecessary surgery. Therefore, an accurate pre-surgery evaluation is crucial. The most reliable diagnostic test for thyroid nodules is fine needle aspiration (FNA) cytology, which accurately distinguishes between a benign and malignant lesion in most cases. However, cytological discrimination between malignant and benign follicular cancer is often difficult because of poor quality samples. Here we describe rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology.