Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya.

Sites in eastern Africa have shed light on the emergence and early evolution of the genus Homo. The best known early hominin species, H. habilis and H. erectus, have often been interpreted as time-successive segments of a single anagenetic evolutionary lineage. The case for this was strengthened by the discovery of small early Pleistocene hominin crania from Dmanisi in Georgia that apparently provide evidence of morphological continuity between the two taxa. Here we describe two new cranial fossils from the Koobi Fora Formation, east of Lake Turkana in Kenya, that have bearing on the relationship between species of early Homo. A partial maxilla assigned to H. habilis reliably demonstrates that this species survived until later than previously recognized, making an anagenetic relationship with H. erectus unlikely. The discovery of a particularly small calvaria of H. erectus indicates that this taxon overlapped in size with H. habilis, and may have shown marked sexual dimorphism. The new fossils confirm the distinctiveness of H. habilis and H. erectus, independently of overall cranial size, and suggest that these two early taxa were living broadly sympatrically in the same lake basin for almost half a million years.

Efficacy of 18F-FDG PET/CT in the evaluation of patients with recurrent cervical carcinoma.

PURPOSE: Only a limited number of studies have evaluated the efficacy of 18F-FDG PET/CT for recurrent cervical carcinoma, which this study seeks to expand upon. METHODS: This is a retrospective study of 30 women with cervical carcinoma who had a surveillance PET/CT after initial therapy. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated using a 2 × 2 contingency table with pathology results (76%) or clinical follow-up (24%) as the gold standard. The Wilson score method was used to perform 95% confidence interval estimations. RESULTS: The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT for the detection of local recurrence at the primary site were 93, 93, 93, 86, and 96%, respectively. The same values for the detection of distant metastases were 96, 95, 95, 96, and 95%, respectively. Seventy-one percent of the scans performed in symptomatic patients showed true-positive findings. In comparison, 44% of scans performed in asymptomatic patients showed true-positive findings. But, all patients subsequently had a change in their management based on the PET/CT findings such that the effect was notable. The maximum standardized uptake value ranged from 5 to 28 (average: 13 ± 7) in the primary site and 3 to 23 (average: 8 ± 4) in metastases which were significantly different (p = 0.04). CONCLUSION: This study demonstrates favorable efficacy of 18F-FDG PET/CT for identification of residual/recurrent cervical cancer, as well as for localization of distant metastases.

Uncommon causes of thyrotoxicosis.

Apart from the common causes of thyrotoxicosis, such as Graves' disease and functioning nodular goiters, there are more than 20 less common causes of elevated free thyroid hormones that produce the symptoms and signs of thyrotoxicosis. This review describes these rarer conditions and includes 14 illustrative patients. Thyrotropin and free thyroxine should be measured and, when the latter is normal, the free triiodothyronine level should be obtained. Measurement of the uptake of (123)I is recommended for most patients.

Treatment of thyrotoxicosis.

In this review, the causes of thyrotoxicosis and the treatment of syndromes with increased trapping of iodine are discussed. The benefits and the potential side effects of 3 frequently used therapies--antithyroid medications, thyroidectomy, and (131)I treatment--are presented. The different approaches to application of (131)I treatment are described. Treatment with (131)I has been found to be cost-effective, safe, and reliable.

Clinical role of 18F-FDG PET/CT in the management of squamous cell carcinoma of the head and neck and thyroid carcinoma.

18F-FDG PET/CT has rapidly become a widely used imaging modality for evaluating a variety of malignancies, including squamous cell carcinoma of the head and neck and thyroid cancer. Using both published data and the multidisciplinary experience at our institution, we provide a practical set of guidelines and algorithms for the use of 18F-FDG PET/CT in the evaluation and management of head and neck cancer and thyroid cancer.

2-Deoxy-2-[F-18]fluoro-D-glucose positron emission tomography/computed tomography in the management of melanoma.

OBJECTIVES: 2-Deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single exam. The role of FDG-PET is proven in a variety of cancers, including melanoma, but the estimates of sensitivity and specificity are based in the majority of the published studies on dedicated PET, not PET/CT. Therefore, we were prompted to review our experience with FDG-PET/CT in the management of melanoma. METHODS: This is a retrospective study on 106 patients with melanoma (20-87 years old; average: 56.8 +/- 15.9), who had whole-body FDG-PET/CT at our institution from January 2003 to June 2005. Thirty-eight patients (35.9%) were women and 68 patients (64.1%) were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. RESULTS: All patients had the study for disease restaging. The primary tumor depth (Breslow's thickness) at initial diagnosis was available for 76 patients (71.7%) and ranged from 0.4 to 25 mm (average: 3.56 mm). The anatomic level of invasion in the skin (Clark's level) was determined for 70 patients (66%): 3, level II; 13, level III; 43, level IV; 11, level V. The administered dose of (18)F FDG ranged from 9.8 to 21.6 mCi (average: 15.4 +/- 1.8 mCi). FDG-PET/CT had a sensitivity of 89.3% [95% confidence interval (CI): 78.5-95] and a specificity of 88% (95% CI: 76.2-94.4) for melanoma detection. CONCLUSION: This study confirms the good results of FDG-PET/CT for residual/recurrent melanoma detection, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk melanoma, prior to selection of the most appropriate therapy.

Recurrent silent thyroiditis: a report of four patients and review of the literature.

Silent thyroiditis, excluding postpartum thyroiditis and destructive amiodarone thyroiditis, is a relatively uncommon cause of thyrotoxicosis and recurrent cases are even rarer. We present four patients with recurrent silent thyroiditis. The number of episodes ranged from two to nine. All four patients had episodes that were similar in duration (4-6 weeks) as well as in their clinical (no viral prodrome or neck pain), biochemical (high total triiodothyronine [T(3)], free thyroxine [T(4)], and low thyrotropin [TSH] presence of antibodies to thyroid antigens), and scintigraphic (low radioiodine uptake) findings. Individual symptoms and symptom-free duration (from 1 to 4 years) were more variable. No associations were found with regard to medications, pregnancies, or other disease states previously implicated in thyroiditis. One patient was unsuccessfully prescribed thyroid hormone to prevent recurrence. Three were treated with radioablative iodine therapy during the recovery phase of an episode; they became hypothyroid and take replacement l-thyroxine. They have remained symptom free.

Treatment of micropapillary carcinoma of the thyroid: where do we draw the line?

Two patients with papillary thyroid cancer were seen in consultation after they had been treated in other medical centers. Their cancers measured 1 and 1.2 mm, respectively. Both patients were treated by two thyroid operations and (131)I ablation. We believe that, apart from lobectomy, these therapies were not justified. We draw attention to this to provide a topic for debate and to attempt to prevent this happening to other patients.

F-18 FDG PET/CT demonstration of an adrenal metastasis in a patient with anaplastic thyroid cancer.

An adrenal metastasis was identified on an F-18 FDG PET/CT scan in a patient with anaplastic thyroid cancer. There are very few reports of thyroid cancer, even anaplastic thyroid cancer, metastasizing to the adrenal.

Incidental gallbladder visualization on nonhepatobiliary nuclear medicine studies: case series and review of the literature.

Gallbladder uptake is occasionally encountered with commonly used nonhepatobiliary radiopharmaceuticals. Identification of the biliary tract by a nonhepatobiliary agent can identify disease, such as uptake of labeled white blood cells. However, in most cases, gallbladder uptake of nonhepatobiliary tracers is not due to pathology in these cases. It is important to avoid attributing gallbladder uptake to disease in the gallbladder or adjacent anatomic structures. We present 3 cases of unexpected gallbladder tracer uptake and provide a review of the literature describing incidental gallbladder uptake on nonhepatobiliary nuclear medicine studies. The potential for misdiagnosis and the steps taken to avoid this are discussed.

F-18 FDG PET/CT in the management of thyroid cancer.

PURPOSE: There are approximately 32,000 new cases of thyroid carcinoma annually in the United States. F-18 FDG PET/CT has an established role in cancer management, including thyroid cancer, usually in patients who are thyroglobulin (Tg) positive/iodine negative. We reviewed our experience with F-18 FDG PET/CT in thyroid cancer, with an emphasis on correlation with Tg, and maximum standardized uptake values (SUV). We also analyzed the role of thyroid stimulating hormone (TSH) on PET/CT results. MATERIALS AND METHODS: This is a retrospective study (January 2003 to December 2006) of 76 patients with differentiated thyroid cancer, who had F-18 FDG PET/CT scans. There were 44 women and 32 men, with age range of 20 to 81 years (average, 51.1 +/- 18.1). The administered doses of F-18 FDG ranged from 396 to 717 MBq (15.8-19.4 mCi) (average, 566 +/- 74.8) (15.3 +/- 2). Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. RESULTS: A total of 98 PET/CT scans were analyzed (59 patients had 1 scan, 12 patients had 2, and 5 patients had 3). PET/CT was 88.6% sensitive (95% CI: 78.-94.3) and 89.3% specific (95% CI: 71.9-97.1). Mean Tg level was 1203 ng/mL (range, 0.5-28,357) in patients with positive PET/CT and 9.72 ng/mL (range, 0.5-123.0) in patients with negative PET/CT scans (P = 0.0389). Mean SUV max was 10.8 (range, 2.5-32) in the thyroid bed recurrence/residual disease and 7.53 (range, 2.5-26.2) in metastatic lesions (P = 0.0114). Mean SUV max in recurrent/residual disease in patients with TSH 30 mIU/L was 8.1 (range, 2.6-32) (P = 0.2994). CONCLUSION: F-18 FDG PET/CT had excellent sensitivity (88.6%) and specificity (89.3%) in this patient population. Metastatic lesions were reliably identified, but were less F-18 FDG avid than recurrence/residual disease in the thyroid bed. TSH levels at the time of PET/CT did not appear to impact the FDG uptake in the lesions or the ability to detect disease. In the setting of high or rising levels of Tg, our study confirms that it is indicated to include PET/CT in the management of patients with differentiated thyroid cancer.

Merkel cell carcinoma: Is there a role for 2-deoxy-2-[f-18]fluoro-D-glucose-positron emission tomography/computed tomography?

PURPOSE: 2-Deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is becoming widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single study. The role of FDG-PET/CT is proven in lymphoma, melanoma, colorectal carcinoma, and other cancers. However, there are rare malignancies such as Merkel cell carcinoma that can potentially be evaluated with PET/CT. We were therefore prompted to review our experience with FDG-PET/CT in the management of patients with Merkel cell carcinoma. PROCEDURES: This is a retrospective case series of six patients with Merkel cell carcinoma, 58-81 years old (average 69 +/- 8.3), who had whole-body PET/CT at our institution from January 1st, 2003 to August 31st, 2005. Two patients were women and four were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. RESULTS: Twelve examinations were acquired for the six patients (one patient had six PET/CT, one patient had two PET/CT, and four patients had one PET/CT). The injected FDG doses ranged 381.1-669.7 MBq (average 573.5 +/- 70.3). Four patients had the PET/CT as part of initial staging, and two patients had the exam for restaging (after surgery and XRT). A total of six Merkel lesions (pancreas, adrenal, lip, submandibular lymph nodes, cervical lymph nodes, and parapharyngeal soft tissue) were identified in three patients and confirmed on histopathological examination. The FDG uptake in these areas was intense, with maximum standardized uptake value (SUVmax) values of 5-14 (average 10.4 +/- 3.8). In one patient, the PET/CT scan identified abnormal focal distal sigmoid uptake that was biopsied and diagnosed as adenocarcinoma. Two patients had negative scans and had no clinical evidence of disease on follow-up office visits (up to one year after PET/CT). CONCLUSIONS: This case series suggests that FDG-PET/CT may have a promising role in the management of patients with Merkel cell carcinoma.

The role of radioactive iodine in the treatment of well-differentiated thyroid cancer.

The prognosis in differentiated thyroid cancer is excellent. The completeness of thyroidectomy and removal of involved regional metastases are the most important elements of management. Iodine 131 has a role in ablating residual thyroid and treating regional and distant metastases. The effectiveness of the treatment is confirmed by negative follow-up scans and low or undetectable Tg. This therapy is relatively specific, but other tissues can receive meaningful doses of radiation and acute and long-term complications can occur. Therefore, whether the patient will have a better prognosis after treatment with 131I and whether the benefits of treatment are greater than the side effects must be determined for every patient.

Metastatic struma ovarii: the burden of truth.

A 58-year-old woman was found to have metastatic thyroid cancer in her liver. This was identified when she was investigated for upper abdominal pain and underwent biopsy of hepatic lesions. She had no palpable thyroid nodule and had a normal ultrasound of the thyroid. Previously, both ovaries had been removed because of tumors. The pathologic findings in one of the ovaries could not be recovered because the procedure was more than 40 years ago, when the patient was a teenager. By a process of elimination, a diagnosis of metastatic struma ovarii was established. Treatment of metastatic thyroid cancer from struma ovarii, including removal of the normal thyroid and administration of I-131, is presented.

F-18 FDG PET/CT evaluation of osseous and soft tissue sarcomas.

INTRODUCTION: Osseous and soft tissue sarcomas (OSTS) represent a histologic heterogeneous group of malignant tumors. Most of the current clinical data on the role of F-18 FDG PET in sarcomas come from patients studied with dedicated PET and less frequently with hardware fusion PET/CT. Therefore, we were prompted to review our experience with F-18 FDG PET/CT in OSTS. METHODS: This is a retrospective study (January 2003-December 2005) of 44 patients with histologic diagnoses of OSTS who had F-18 FDG PET/CT at our institution. The group included 22 men and 22 women with an age range of 2 of 84 years (average, 37 +/- 20.2 years). The administered doses of F-18 FDG range 4.1 to 19.5 mCi (average, 14.3 +/- 3 mCi). Reinterpretation of the imaging studies for accuracy and data analysis from medical records was performed. RESULTS: The sensitivity and specificity of combined F-18 FDG PET/CT were 100% (95% confidence interval [CI] = 75.7-100) and 93.3% (95% CI = 78.7-98.1) for the primary OSTS, and 80% (95% CI = 58.4-91.9) and 86.4% (95% CI = 66.7-95.2) for metastases. When interpreted separately, CT outperformed PET for pulmonary metastases detection: CT was 76.5% sensitive and 88% specific, whereas PET was only 57.1% sensitive but 96.4% specific. For detection of other metastases, CT was 82.3% sensitive and 76% specific, with PET demonstrating 78.6% sensitivity and 92.8% specificity. CONCLUSION: Relatively similar results (except better specificity for PET and PET/CT) were noted when examining the rate of metastases detection, excluding pulmonary lesions. However, CT had a better detection rate for pulmonary metastases when compared with PET alone. A negative PET scan in the presence of suspicious CT findings in the chest cannot reliably exclude pulmonary metastases from OSTS.

Replication of adenovirus mini-chromosomes.

We have isolated adenovirus origins of DNA replication from both the right and left ends of the genome, which are functional on linear autonomously replicating mini-chromosomes. The mini-chromosomes contain two cloned inverted adenovirus termini and require non-defective adenovirus as a helper. Replicated molecules are covalently attached to protein, and DNA synthesis is initiated at the correct nucleotide even when the origins are not located at molecular ends. The activity of embedded origins leads to the generation of linear mini-chromosomes from circular or linear molecules. These observations therefore suggest that sequences within the adenovirus origin of replication position the protein priming event at the adenovirus terminus. Experiments investigating the regeneration of deleted viral inverted terminal repeat sequences show a sequence-independent requirement for inverted sequences in this process. This result strongly suggests that repair results from the formation of a panhandle structure by a displaced single strand. On the basis of these observations we propose a model for the generation of adenovirus mini-chromosomes from larger molecules.

Prediction of satisfactory response to pleural sclerosis using radiopharmaceuticals: study in a patient with cirrhotic hydrothorax and LeVeen shunt.

Rapidly recurring right pleural effusion was a disabling clinical problem in a 51-year-old woman with alcoholic cirrhosis that had not been relieved by diuretic therapy or a LeVeen shunt. By injecting technetium Tc 99m albumin aggregated into the peritoneal cavity, shunt patency and rapid flow into the pleural effusion were demonstrated. In contrast, technetium Tc 99m albumin aggregated injected injected into the pleural fluid showed no movement into the abdominal cavity. These test results predicted that pleural sclerosis would help her clinical problem but would not place the abdominal contents in jeopardy. This prediction has proved to be correct.

Graves' hyperthyroidism. Spontaneous occurrence after autoimmune hypothyroidism with persistent infiltrative ophthalmopathy.

The clinical course of a 39-year-old woman who exhibited uncommon features of autoimmune thyroid disease was followed. The patient's thyroid status changed from hypothyroid to hyperthyroid spontaneously. She also had severe infiltrative ophthalmopathy when she was hypothyroid. The unusual sequence of her condition raises some speculation about the pathogenesis of autoimmune hyperthyroidism and ophthalmopathy. The study also indicates that treatment of hypothyroidism may occasionally not be lifelong.

Indium 111 WBC scan in local and systemic fungal infections.

We describe two patients-one with a systemic fungal infection and one with a localized form-who had strikingly abnormal indium 111 leukocyte (WBC) scans. The patient with systemic disease had an abnormal WBC scan before lesions became clinically apparent.

Treatment guidelines for patients with thyroid nodules and well-differentiated thyroid cancer. American Thyroid Association.

A set of minimum clinical guidelines for use by primary care physicians in the evaluation and management of patients with thyroid nodules or thyroid cancer was developed by consensus by an 11-member Standards of Care Committee (the authors of the article) of the American Thyroid Association, New York, NY. The participants were selected by the committee chairman and by the president of the American Thyroid Association based on their clinical experience. The committee members represented different geographic areas within the United States, to reflect different practice patterns. The guidelines were developed based on the expert opinion of the committee participants, as well as on previously published information. Each committee participant was initially assigned to write a section of the document and to submit it to the committee chairman, who revised and assembled the sections into a complete draft document, which was then circulated among all committee members for further revision. Several of the committee members further revised and refined the document, which was then submitted to the entire membership of the American Thyroid Association for written comments and suggestions, many of which were incorporated into a final draft document, which was reviewed and approved by the Executive Council of the American Thyroid Association.