• Korean Journal of Radiology
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• v.21 no.5
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• pp.537-540
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• 2020

Recently, some global cases of 2019 novel coronavirus (COVID-19) pneumonia have been caused by second- or third-generation transmission of the viral infection, resulting in no traceable epidemiological history. Owing to the complications of COVID-19 pneumonia, the first symptom and imaging features of patients can be very atypical and early diagnosis of COVID-19 infections remains a challenge. It would aid radiologists and clinicians to be aware of the early atypical symptom and imaging features of the disease and contribute to the prevention of infected patients being missed.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6337-6340
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• 2013

Through retrospective analysis of 13 cases of magnetic resonance image (MRI) manifestations of atypical meningiomas confirmed by operation and pathology in the First Affiliated Hospital of Xinxiang Medical University, the objective of this study was to evaluate the diagnostic value of MRI in order to improve the accuracy rate of preoperative diagnosis. In this retrospective analysis of MRI findings for atypical meningiomas in First Affiliated Hospital of Xinxiang Medical University from January to July in 2012, the location, morphology and tumor signals and other tumor imaging characteristics were covered. In 13 cases of atypical meningioma patients of this group, most tumors were located at typical sites (10/13), mainly the falx cerebri, parasagittal, convexity, saddle area. Only two cases were at atypical locations, 1 in the cerebellar hemisphere and 1 in a lateral ventricle. Most of the tumors showed T1 and T2 isointensity signals, and necrosis, calcification, and peritumoral edema were always featured. DWI showed isointensity in 11 cases (11/13), and hyperintensity in 2. Some 9 cases had dural tail signs, 12 had accurate positioning (12/13), and 2 were postoperative recurrences. MRI has high value in the diagnosis of atypical meningiomas, with important roles in early clinical diagnosis, treatment and prognosis evaluation.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.43-54
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• 2024

Objective: To evaluate the added value of diffusion-weighted imaging (DWI)-based quantitative parameters to distinguish uterine sarcomas from atypical leiomyomas on preoperative magnetic resonance imaging (MRI). Materials and Methods: A total of 138 patients (age, 43.7 ± 10.3 years) with uterine sarcoma (n = 44) and atypical leiomyoma (n = 94) were retrospectively collected from four institutions. The cohort was randomly divided into training (84/138, 60.0%) and validation (54/138, 40.0%) sets. Two independent readers evaluated six qualitative MRI features and two DWI-based quantitative parameters for each index tumor. Multivariable logistic regression was used to identify the relevant qualitative MRI features. Diagnostic classifiers based on qualitative MRI features alone and in combination with DWI-based quantitative parameters were developed using a logistic regression algorithm. The diagnostic performance of the classifiers was evaluated using a cross-table analysis and calculation of the area under the receiver operating characteristic curve (AUC). Results: Mean apparent diffusion coefficient value of uterine sarcoma was lower than that of atypical leiomyoma (mean ± standard deviation, 0.94 ± 0.30 10^-3 mm²/s vs. 1.23 ± 0.25 10^-3 mm²/s; P < 0.001), and the relative contrast ratio was higher in the uterine sarcoma (8.16 ± 2.94 vs. 4.19 ± 2.66; P < 0.001). Selected qualitative MRI features included ill-defined margin (adjusted odds ratio [aOR], 17.9; 95% confidence interval [CI], 1.41-503, P = 0.040), intratumoral hemorrhage (aOR, 27.3; 95% CI, 3.74-596, P = 0.006), and absence of T2 dark area (aOR, 83.5; 95% CI, 12.4-1916, P < 0.001). The classifier that combined qualitative MRI features and DWI-based quantitative parameters showed significantly better performance than without DWI-based parameters in the validation set (AUC, 0.92 vs. 0.78; P < 0.001). Conclusion: The addition of DWI-based quantitative parameters to qualitative MRI features improved the diagnostic performance of the logistic regression classifier in differentiating uterine sarcomas from atypical leiomyomas on preoperative MRI.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.18 no.2
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• pp.144-148
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• 2015

Hepatocellular adenomas are a benign, focal, hepatic neoplasm that have been divided into four subtypes according to the genetic and pathological features. The ${\beta}$-catenin activated subtype accounts for 10-15% of all hepatocellular adenomas and specific magnetic resonance imaging features have been defined for different hepatocellular adenomas subtypes. The current study aimed to report the magnetic resonance imaging features of a well differentiated hepatocellular carcinoma that developed on the basis of ${\beta}$-catenin activated hepatocellular adenomas in a child. In this case, atypical diffuse steatosis was determined in the lesion. In the literature, diffuse steatosis, which is defined as a feature of the hepatocyte nuclear factor-$1{\alpha}$-inactivated hepatocellular adenomas subtype, has not been previously reported in any ${\beta}$-catenin activated hepatocellular adenomas case. Interlacing magnetic resonance imaging findings between subtypes show that there are still many mysteries about this topic and larger studies are warranted.

• Journal of the Korean Society of Radiology
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• v.84 no.6
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• pp.1266-1289
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• 2023

Malignant lymphoma typically presents with homogeneous enhancement of enlarged lymph nodes without internal necrotic or cystic changes on multiphasic CT, which can be suspected without invasive diagnostic methods. However, some subtypes of malignant lymphoma show atypical imaging features, which makes diagnosis challenging for radiologists. Moreover, there are several lymphoma-mimicking diseases in current clinical practice, including leukemia, viral infections in immunocompromised patients, and primary or metastatic cancer. The ability of diagnostic processes to distinguish malignant lymphoma from mimicking diseases is necessary to establish effective management strategies for initial radiological examinations. Therefore, this study aimed to discuss the typical and atypical imaging features of malignant lymphoma as well as mimicking diseases and discuss important diagnostic clues that can help narrow down the differential diagnosis.

• Archives of Craniofacial Surgery
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• v.20 no.2
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• pp.139-143
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• 2019

Here we report a case of a focal atypical proliferative nodule (PN) arising from a congenital melanocytic nevus (CMN). Diagnosis was challenging because it had both benign and malignant clinical features. Unusual histopathology, immunohistochemistry, and intraoperative findings of this atypical PN are discussed. A 5-year-old girl was admitted for a congenital $5{\times}5cm$ sized scalp mass. This hemangioma-like soft mass showed biphasic characteristics such as a slow, gradual, and benign increase in size but worrisome dural invasion with cranial bone defect. We removed the scalp mass with clear resection margins. Interoperatively, we found that the cranial bone defect had already filled. Histopathologic examination showed CMN with focal atypical PN. The nodule showed sharp demarcation and cellular pleomorphism. However, in immunohistochemical study, Ki-67 proliferation index and expression levels of protein S-100 and Melan-A were very low. These were unusual findings of atypical PNs. Despite her worrisome preoperative radiologic features, she showed an indolent clinical course compatible with previously reported biologic behavior. The patient underwent follow-up inspection with magnetic resonance imaging every 6 months for up to 3 years. The nodule appeared to be stationary at the last visit.

• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.808-829
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• 2022

Hepatocellular carcinoma (HCC) can be diagnosed noninvasively on multiphasic CT and MRI based on its distinctive imaging findings. These features include arterial phase hyperenhancement and washout on portal or delayed phase images. However, radiologists face significant diagnostic challenges because some HCCs exhibit atypical imaging characteristics. In addition to many HCC-mimicking lesions, such as arterioportal shunts, combined HCC-cholangiocarcinoma, intrahepatic cholangiocarcinoma, and hemangioma present a challenge for radiologists in actual clinical practice. The ability to distinguish HCCs from mimickers on initial imaging examinations is crucial for appropriate management and treatment decisions. Therefore, this pictorial review presents the imaging findings of atypical HCCs and HCCs mimicking malignant and benign lesions and discusses important clues that may help narrow down the differential diagnosis.

• Journal of Yeungnam Medical Science
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• v.39 no.1
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• pp.53-57
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• 2022

Hepatic hemangiomas infrequently exhibit atypical imaging features, which may cause diagnostic confusion with hepatic malignancies and lead to unnecessary surgery. We report a rare case of multilocular cystic hemangioma of the liver mimicking a mucinous cystic neoplasm of the liver in a 48-year-old female, focusing on computed tomography and magnetic resonance imaging features and their differential diagnosis.

• Investigative Magnetic Resonance Imaging
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• v.19 no.1
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• pp.62-66
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• 2015

Lymphoplasmacyte-rich meningioma is a rare WHO Grade I subtype of meningioma. The lymphoplasmacyte-rich meningioma does not have typical imaging features of a meningioma so it can mimic intracranial inflammatory condition or brain neoplasm. We report the clinicopathologic features of lymphoplasmacyte-rich meningioma in a 35-year-old woman. She suffered from progressive headache, dizziness and tinnitus over two years. The tumor exhibited atypical neuroimaging features, including obvious peritumoral edema and irregular enhancing components. She underwent total resection and histologic examination revealed a meningioma with numerous plasma cells. Her symptoms have since resolved and there has been no evidence of tumor recurrence after one year of follow-up.

• Investigative Magnetic Resonance Imaging
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• v.24 no.3
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• pp.162-167
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• 2020

Disseminated peritoneal leiomyomatosis (DPL) is a very rare benign disease, characterized by multiple solid subperitoneal or peritoneal smooth muscle nodules in abdominopelvic cavity and malignant transformation is extremely rare. Also, uterine smooth muscle tumors of unknown malignant potential (STUMP) is a rare tumor, which is regarded as subclassification in uterine smooth muscle tumors between benign and malignant criteria. Pathogenesis of DPL is uncertain, but increasing evidence of iatrogenic cause including laparoscopic myomectomy has been reported. We report a case of a 28-year-old female with previous history of laparoscopic myomectomy diagnosed with DPL with atypical feature and concurrent uterine STUMP using computed tomography (CT) and magnetic resonance imaging (MRI), as well as present a review of the literature.