TIROSEC: Molecular, Clinical and Histopathological Profile of Papillary Thyroid Carcinoma in a Colombian Cohort.

INTRODUCTION: In Colombia, thyroid cancer ranks among the highest incidences, yet our population lacks studies on its molecular profile. This study aims to characterize clinical, histopathologic and molecular data in a Colombian cohort with papillary thyroid carcinoma (PTC). METHODS: A retrospective review of clinical history, clinicopathologic characteristics, treatment and 5-10-year follow-up for all patients was done. DNA and RNA were extracted from formalin-fixed paraffin-embedded (FFPE) tissue using the Quick-DNA & RNA FFPE Min iPrep kit (Zymo Research). Next-generation sequencing (NGS) analysis was performed with SOPHiA Solid Tumor Solutions kit (SOPHiA GENETICS). Tumor mutation genomic analysis used SOPHiA DDM™ platform, with descriptive analysis reporting frequencies, means and associations via chi-square analysis. RESULTS: Among 231 sequenced patients, mean age at diagnosis was 46 (± 12.35) years, with higher frequency in women (81.82%). Two cases were reclassified as non-invasive follicular thyroid neoplasm (NIFT-P); an NRAS mutation was found in one of them. Predominant histologic subtype was classic PTC (57.64%) followed by tall cell (28.82%). Of the 229 sequenced carcinomas, mutations were identified in 186 cases, including BRAF, IDH1, RAS and PIK3CA. Notable copy number variations (CNVs) were PDGFRA, CDK4 and KIT, with RET being the most frequent gene fusion, including CCDC6-RET in two classic subtype cases. CONCLUSION: This is the first study in Colombia (TIROSEC) to our knowledge that integrates molecular and histopathologic profiles enriching our local comprehension and knowledge of PTC. The identification of target mutations such as BRAF, RET and NTRK fusions holds the potential to guide targeted therapies for tumor recurrence and predict aggressive behavior.

Medical Imagery: Cytomegalovirus sialadenitis in a patient with B-cell acute lymphoblastic leukemia.

Cytomegalovirus (CMV) can cause a broad range of diseases, with severity depending on immune status, comorbidities, and age. Initial CMV infection usually occurs in childhood and is typically asymptomatic, leading to lifelong latency. In immunocompromised patients, CMV can affect multiple organs, but salivary gland infections are rare. This study presents a case of a 66-year-old woman with B-cell acute lymphoblastic leukemia who developed swelling and pain in the right preauricular region during pre-transplant consolidation therapy. Despite a recent bone marrow biopsy indicating morphological remission and a flow cytometry analysis detecting only 0.04 % B lymphoblasts, she exhibited these symptoms. A CT scan revealed enlargement, hyperdensity, and enhancement of the right parotid glands, with accompanying subcutaneous edema. A biopsy of the right parotid gland showed a dense interstitial lymphoplasmacytic infiltrate with numerous Cowdry bodies and smaller granular cytoplasmic inclusions, all testing positive for CMV immunohistochemistry. The findings confirm the diagnosis of CMV sialadenitis in an immunocompromised patient. This case underscores the importance of considering CMV infections in similar clinical scenarios, particularly in patients with compromised immune systems.