Kana Ogisawa

The Value of Ultrasound-Guided Fine-Needle Aspiration Cytology for Thyroid Nodules: An Assessment of Its Diagnostic Potential and Pitfalls

Abstract This study was conducted to assess the diagnostic potential and pitfalls of performing fine-needle aspiration cytology (FNAC) for thyroid nodules. We retrospectively analyzed 1012 aspirated samples obtained from 806 thyroid nodules by the ultrasound (US)-guided method. Of these 806 nodules, 226 (31%) had been surgically treated, 152 (67%) of which were histologically diagnosed as malignant. The rate of sufficient aspirate was 82%, being lower in nodules with a diameter of less than 5 mm (73%, P = 0.10); either calcified (77%, P = 0.043) or benign (72%, P = 0.0002). The accuracy of FNAC was 75%, the rate of indeterminate diagnosis was 16%, the false negative rate was 13%, and the positive malignancy rate was 99%. The rate of indeterminate diagnosis was higher in adenomatous goiter, follicular carcinoma, and malignant lymphoma, at P = 0.015, P = 0.0008, and P = 0.035, respectively. The accuracy was lower in follicular carcinoma and malignant lymphoma (both at P = 0.013). Sufficient aspirate was finally obtained from 701 (87%) of the 806 nodules by repeated aspiration. Of 152 malignant nodules, 28 (18%) were diagnosed after two or more aspirations, and the accuracy was improved to 81% by repeating the procedure. These findings indicated that repeated aspiration may be a simple and effective method of improving the diagnostic potential of FNAC.

Peroxisome proliferator-activated receptor gamma activation induces cell cycle arrest via the p53-independent pathway in human anaplastic thyroid cancer cells.

Anaplastic thyroid carcinoma is one of the most aggressive human malignancies. Outcomes of intensive multimodal therapy have been far from satisfactory. Furthermore, p53 gene dysfunction, often found in this type of cancer, is known to impair the efficacy of the therapeutic agents. Specific ligands for peroxisome proliferator activated receptor gamma (PPAR‐γ) induce growth suppression in some tumor cells. In this study, we investigated the role of PPAR‐γ in anaplastic thyroid cancer cell lines (OCUT‐1, ACT‐1). PPAR‐γ was expressed and functional in both cell lines. Activation of PPAR‐γ with its specific ligands, troglitazone and 15‐deoxy‐Δ12, 14‐prostaglandin J2, inhibited cell growth in a dose‐dependent manner through inducing G1 cell cycle arrest. P53 protein expression differed in OCUT‐1 and in ACT‐1, though the levels stayed constant irrespective of ligand exposure in both cell lines. In contrast, p21 and p27 proteins were induced in a dose‐dependent manner in both situations. This study showed that PPAR‐γ ligands were able to induce growth suppression in anaplastic thyroid cancer cells via a p53‐independent, but p21‐ and p27‐dependent cytostatic pathway. These tumor‐suppressive effects of PPAR‐γ may provide a novel approach to the treatment of anaplastic thyroid cancer.

Telomerase Activation and Expression of its Catalytic Subunits in Benign and Malignant Tumors of the Parathyroid

Purpose.Telomerase activity (TA) has been extensively studied in tumors of many organs, but not the parathyroid gland. Therefore, we investigated TA in parathyroid tumors, and examined the mRNA expression of its catalytic subunits.Methods.We examined 17 single adenomas, one hyperplastic parathyroid gland, and one metastatic parathyroid cancer and quantified TA by fluorescence-based TRAP analysis. We also studied the expression of telomerase catalytic subunits in nine adenomas and one cancer by reverse transcription – polymerase chain reaction (RT-PCR) analysis.Results.Telomerase activity was not detected in any of the adenomas or the hyperplastic gland; however, the metastatic cancer was highly positive for TA. Both human telomerase RNA (hTR) and human telomerase-associated pretein (hTEP-1) mRNA were detected universally in every specimen tested. Conversely, human telomerase reverse transcriptase (hTERT) mRNA was not detected by the conventional electrophoresis-based technique. Faint expression of hTERT mRNA was detected by real-time RT-PCR only in the sample of parathyroid cancer.Discussion.We hypothesize that TA plays a role in the malignant transformation of parathyroid disease and suggest that hTERT mRNA expression could be the key step for TA as in other malignancies. Telomerase activity and hTERT may be useful molecular targets of parathyroid cancer.

Laparoscopic adrenalectomy for benign adrenal tumors

Laparoscopic adrenalectomy has been rapidly accepted for treatment of benign adrenal tumors. To evaluate the advantages of laparoscopic adrenalectomy, we examined 55 patients who underwent laparoscopic adrenalectomy. In all patients, adrenal tumors were successfully removed. The mean operating time was 143 minutes, and the estimated mean blood loss was 49 mL in all patients. The postoperative course was uneventful in all cases. The mean frequency of administration of analgesics was only 2.9 times, and the time elapsed to first walking after surgery was 17 hours. The peak white blood cell count and C-reactive protein values after surgery were 8,266 +/- 1,963/mm3 and 2.5 +/- 1.2 mg/dL, respectively. Of the 55 patients, 44 underwent total adrenalectomy and another 11 underwent partial adrenalectomy, which was introduced in the expectation of preserving normal adrenal cortex; it is therefore indicated in solitary and peripherally located benign tumors. The mean operating time was 154 minutes for the total adrenalectomy, which was longer than that of partial adrenalectomy (92 minutes). The estimated blood loss was 50 mL for the total and 46 mL for the partial adrenalectomy. The postoperative course was uneventful and surgical outcome was excellent in each group. In conclusion, our results are encouraging enough to suggest that laparoscopic adrenalectomy should be a preferential therapeutic option for benign adrenal tumors; also, partial adrenalectomy could be a safe, effective, and less invasive procedure in selected cases.