Detecting residual soft tissue sarcoma after unplanned excision; model-free analysis of dynamic contrast-enhanced MRI at short-term follow-up.

OBJECTIVES: To evaluate diagnostic utility of additional DCE-MRI for detecting residual soft tissue sarcomas (STS) after unplanned excision (UPE). METHODS: We retrospectively evaluated 32 patients with UPE of STS, followed by conventional MRI with DCE-MRI and wide excision (WE), between November 2019 and January 2022. Residual tumors on conventional MRI were categorized into three groups: Lesion-type-0, no abnormal enhancement, Lesion-type-1, an indeterminate lesion, and Lesion-type-2, a definite enhancing nodule. On DCE-MRI, ROIs were manually placed on enhancing areas of suspected residual tumor. The mean and 95th percentile values of AUC of time-intensity curve were calculated at 60, 90, and 120 s of Enhancement-cycle-1 and -2. Optimal DCE parameters were identified by ROC analysis. Diagnostic performance of conventional MRI and DCE-MRI was compared using McNemar's test. RESULTS: On WE, residual tumor was present in 23 (71.9%) of 32 patients. On MRI, Lesion-type-1 was found in 16/32 (50%) patients and Lesion-type-2 in 16/32 (50%). The optimal DCE parameter was the 95th percentile value of AUC at 120s of Enhancement-cycle-2. The sensitivity, specificity, and AUC were as follows: 65.2% (95% CI, 45.8-85.7%), 88.9% (CI, 68.4-100%), and 0.77 (CI, 0.62-0.92) for conventional MRI, and 100%, 55.6% (CI, 23.1-88.0%), and 0.78 (CI, 0.61-0.95) for combined conventional and DCE-MRI. CONCLUSIONS: Additional DCE-MRI aided in detecting residual STS after UPE, particularly in cases without definite soft tissue nodular enhancement. ADVANCES IN KNOWLEDGE: Close follow up may be suggested for patients showing abnormality in DCE-MRI, with more suspicion of residual tumor.

Primary Central Nervous System Involvement in Peripheral T-Cell Lymphoma: A Case Report.

Primary central nervous system T-cell lymphoma (PCNSTL) is an extremely rare type of brain tumor. There are only few reports on the imaging findings of patients with PCNSTL. Herein, we report the imaging findings of a patient with peripheral T-cell lymphoma-not otherwise specified that presented with numerous small nodular and patchy strongly enhancing lesions on MRI.

Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma in a Child: A Case Report.

The diffuse sclerosing variant of papillary thyroid carcinoma (DSPTC) is uncommon. Herein, we report a rare case of DSPTC in a 9-year-old girl who initially presented with a painless diffuse goiter. Thyroid peroxidase antibody testing yielded positive results, and the initial clinical diagnosis was Hashimoto's thyroiditis. However, thyroid ultrasonography revealed characteristic findings of DSPTC, which was confirmed through the postoperative histopathological diagnosis. Although thyroid cancers are rare in the pediatric population, DSPTC should be included in the differential diagnosis of goiter in these patients. Moreover, ultrasonography may prevent a diagnostic delay and facilitate the detection of a concomitant malignancy.