Differentiation of follicular carcinomas from adenomas using histogram obtained from diffusion-weighted MRI.

AIM: To evaluate the role of histogram analysis of apparent diffusion coefficient (ADC) maps from diffusion-weighted imaging (DWI) in the differentiation of follicular thyroid carcinoma (FTC) from follicular adenoma (FA) in nodules indeterminate on ultrasound-guided core needle biopsy (USCNB). MATERIALS AND METHODS: This study was performed with institutional review board approval. Seventeen patients who were planned to undergo diagnostic lobectomy for an indeterminate thyroid nodule (atypical of unknown significance/follicular lesion of undetermined significance [AUS/FLUS] or suspicious for follicular neoplasm/follicular neoplasm [SFN]) on USCNB were enrolled prospectively. All patients underwent DWI on the day before surgery. Histogram parameters were derived from ADC values obtained from the whole extent of the tumours. The parameters were compared with the final diagnosis based on histopathological examination after surgery. The accuracy of the parameters in differentiating FTC from FA was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: Twelve patients were confirmed as having FA and five patients as having FTC. Histogram parameters including the 10th (ADC10), 25th (ADC25), and 50th (ADC50) percentiles of the ADC values were significantly lower in FA than in FTC (p < 0.05, all). ROC curve analysis revealed that ADC25 resulted in the highest AUC (0.867; confidence interval, 0.616-0.980), with a cut-off value of 0.352×10-3 mm2/s. CONCLUSION: Histogram parameters from ADC maps could differentiate FTC from FA effectively in indeterminate nodules on USCNB, with ADC25 being the most promising parameter.

Risk of malignancy according to sub-classification of the atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) category in the Bethesda system for reporting thyroid cytopathology.

OBJECTIVE: According to the Bethesda System for Reporting Thyroid Cytopathology, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is a heterogeneous category that includes cases with architectural and/or nuclear atypia insufficient to warrant classification as malignant neoplasms. The ambiguous and descriptive characteristics of the AUS/FLUS category mean that the impact of the present guidelines on repeat fine needle aspiration (FNA) is unclear. The present study reclassified AUS/FLUS cases into four sub-categories and then correlated them with histological or cytological follow-up data to clarify the risk of malignancy. METHODS: Ninety-four cases of AUS/FLUS with available follow-up data were reviewed and assigned to one of four sub-categories: (i) AUS-N (nuclear atypia); (ii) AUS-A (architectural atypia); (iii) AUS-O (predominant oncocytic changes); and (iv) AUS-N/A (both nuclear and architectural atypia). The four sub-categories were correlated with subsequent histological or cytological follow-up data, including core needle biopsy, resection, or repeat FNA. RESULTS: Malignancy was identified in 34 of 94 cases (36.2%). The upper limit estimate for malignancy was 43.6%, and the lower limit estimate was speculated as 9.8%. The malignancy rate was highest in cases within the AUS-N sub-category (65.8%, range 16.6%-78.1%). CONCLUSIONS: The present study suggests that cases in the AUS/FLUS category have a higher risk of malignancy than previously thought. Because of the heterogeneous nature of the AUS/FLUS category, further sub-classification might be more effective in achieving appropriate risk stratification and better clinical management.

The Role of Core Needle Biopsy and Its Impact on Surgical Management in Patients with Medullary Thyroid Cancer: Clinical Experience at 3 Medical Institutions.

BACKGROUND AND PURPOSE: Medullary thyroid carcinoma is an uncommon malignancy that is challenging to diagnose. Our aim was to present our experience using core needle biopsy for the diagnosis of medullary thyroid carcinoma compared with fine-needle aspiration. MATERIALS AND METHODS: Between January 2000 and March 2012, 202 thyroid nodules in 191 patients were diagnosed as medullary thyroid cancer by using sonography-guided fine-needle aspiration, core needle biopsy, or surgery. One hundred eighty-three thyroid nodules in 172 patients were included on the basis of the final diagnosis. We evaluated the sensitivity and positive predictive value of fine-needle aspiration and core needle biopsy for the diagnosis of medullary thyroid cancer. We compared the rate of a delayed diagnosis, a diagnostic surgery, and surgery with an incorrect diagnosis for fine-needle aspiration and core needle biopsy and investigated the factors related to the fine-needle aspiration misdiagnosis of medullary thyroid cancer. RESULTS: Fine-needle aspiration showed 43.8% sensitivity and 85.1% positive predictive value for the diagnosis of medullary thyroid cancer; 25.7% (44/171) of patients had a delayed diagnosis, while 18.7% (32/171) underwent an operation for accurate diagnosis, and 20.5% (35/171) underwent an operation with an incorrect diagnosis. Core needle biopsy achieved 100% sensitivity and positive predictive value without a delay in diagnosis (0/22), the need for a diagnostic operation (0/22), or an operation for an incorrect diagnosis (0/22). A calcitonin level of <100 pg/mL was the only significant factor for predicting the fine-needle aspiration misdiagnosis of medullary thyroid cancer (P = .034). CONCLUSIONS: Core needle biopsy showed a superior sensitivity and positive predictive value to fine-needle aspiration and could optimize the surgical management in patients with medullary thyroid cancer. Because the ability of fine-needle aspiration to diagnose medullary thyroid cancer significantly decreases in patients with serum calcitonin levels of <100 pg/mL, core needle biopsy could be indicated for these patients to optimize their surgical management.

Pleuropulmonary and abdominal paragonimiasis: CT and ultrasound findings.

OBJECTIVES: The purpose of this study was to review radiological images of patients with Paragonimus westermani (PW) that simultaneously involved the chest and abdomen. METHODS: Our study included four patients with serologically and histopathologically confirmed paragonimiasis. Abdomen CT (n=3) and chest CT (n=3) scans were available, and abdominal wall ultrasonography was performed in all patients. We retrospectively reviewed the clinical, radiological and histopathological findings of these patients. RESULTS: The most common abdominal CT findings were ascites and intraperitoneal or abdominal wall nodules. Low-attenuated serpentine lesions of the liver were another common and relatively specific feature. CONCLUSION: Radiologists should consider the possibility of PW when these abdominal CT findings are noted, especially with pleural effusion or subpleural nodules in patients with initial abdominal symptoms.

Cytomorphological changes after ultrasound-guided percutaneous ethanol injection in benign thyroid nodules.

OBJECTIVE: To characterize the cytomorphological changes after percutaneous ethanol injection (PEI) in benign thyroid nodules, we compared the cytological features of fine needle aspiration cytology (FNAC) samples before and after PEI. METHODS: Fifty-five cases diagnosed with adenomatous goitre (group 1, 35 cases) or cystic changes only (group 2, 20 cases) were included. In all cases, FNACs were performed by the pathologists before and after PEI. PEI was performed in all cases by a diagnostic radiologist according to the ultrasound guidelines. The following cytological features were evaluated by two pathologists: cellularity of follicular epithelial cells, background, cellular pleomorphism, nuclear/cytoplasmic (N/C) ratio, chromatin pattern, presence of nucleoli, macrophages, multinucleated giant cells, and mitosis. RESULTS: In group 1, 19 cases (54%) showed changes in cellularity after PEI, with reduced cellularity in 13 cases (37%) and increased cellularity in six cases (17%). No necrotic background was observed before PEI; however, 14 cases (40%) developed necrotic background after PEI (P < 0.0001). Multinucleated giant cells were observed in 18 cases (51%) after PEI, which is in contrast to four cases (11%) before PEI (P = 0.001). In group 2, necrotic background was seen in 11 cases (55%, P < 0.0001) and multinucleated giant cells were observed in four cases (20%) after PEI. CONCLUSIONS: Necrotic background and presence of multinucleated giant cells are indicative of tissue damage caused by PEI in the FNAC specimens of benign thyroid nodules. In contrast to other modalities including chemotherapy or radiation treatment for malignant tumour, no unusual cytological change is observed after PEI.