De Novo Extramedullary Plasmacytoma of Thyroid Cartilage.

ABSTRACT: Myeloma involving the laryngeal cartilage is rare, whereas extramedullary plasmacytoma involving only the thyroid cartilage is even rarer. No case of de novo extramedullary plasmacytoma involving thyroid cartilage has been published so far. Hence, it was a diagnostic challenge for clinicians, radiologists, and pathologists. Here, we presented a case of a 61-year-old man who had fixed right laryngeal swelling. After 18 F-FDG PET/CT, biopsy, and myeloma workup, it was found to be plasmacytoma involving the right thyroid cartilage lamina. This case highlighted the rarity of this presentation and the importance of keeping in mind this differential to lead toward diagnosis.

Combined Diagnostic Accuracy of Diffusion and Perfusion MR Imaging to Differentiate Radiation-Induced Necrosis from Recurrence in Glioblastoma.

We aimed to use quantitative values derived from perfusion and diffusion-weighted MR imaging (PWI and DWI) to differentiate radiation-induced necrosis (RIN) from tumor recurrence in Glioblastoma (GBM) and investigate the best parameters for improved diagnostic accuracy and clinical decision-making. Methods: A retrospective analysis of follow-up MRI with new enhancing observations was performed in histopathologically confirmed subjects of post-treated GBM, who underwent re-surgical exploration. Quantitative estimation of rCBV (relative cerebral blood volume) from PWI and three methods of apparent diffusion coefficient (ADC) estimation were performed, namely ADC R1 (whole cross-sectional area of tumor), ADC R2 (only solid enhancing lesion), and ADC R3 (central necrosis). ROC curve and logistic regression analysis was completed. A confusion matrix table created using Excel provided the best combination parameters to ameliorate false-positive and false-negative results. Results: Forty-four subjects with a mean age of 46 years (range, 19−70 years) underwent re-surgical exploration with RIN in 28 (67%) and recurrent tumor in 16 (33%) on histopathology. rCBV threshold of >3.4 had the best diagnostic accuracy (AUC = 0.93, 81% sensitivity and 89% specificity). A multiple logistic regression model showed significant contributions from rCBV (p < 0.001) and ADC R3 (p = 0.001). After analysis of confusion matrix ADC R3 > 2032 × 10−6 mm2 achieved 100% specificity with gain in sensitivity (94% vs. 56%). Conclusions: A combination of parameters had better diagnostic performance, and a stepwise combination of rCBV and ADC R3 obviated unnecessary biopsies in 10% (3/28), leading to improved clinical decision-making.

Incidental detection of Zinner syndrome in a patient with nonseminomatous germ cell tumor of testis.

Zinner syndrome is a rare congenital abnormality occurring in males comprising a triad of unilateral renal agenesis, ipsilateral ejaculatory duct obstruction, and seminal vesicle cyst. Most patients remain asymptomatic, and some may present with lower urinary tract symptoms or infertility. We present a case of incidentally detected Zinner syndrome in a patient with nonseminomatous germ cell tumor of testis, an association that is not reported in literature to our knowledge.