RESUMO
BACKGROUND: Chest wall tuberculosis (TB) and triple-negative essential thrombocythemia (TN-ET) are rare medical conditions, and their combination is extremely rare globally. Only one case of TB peritonitis with thrombocytosis has been reported, which was identified in 1974. CASE SUMMARY: Herein, we report the case of a 23-year-old man with concurrent chest wall mass and TN-ET. The patient presented to a local hospital due to having a headache and low-grade fever for 2 d, with their bodily temperature fluctuating at around 36.8 °C. Hematological analysis showed a high platelet count of 1503 × 109/L. Subsequently, the patient visited our hospital for further investigation. Computed tomography of the chest suggested a submural soft tissue density shadow in the left lower chest wall. After surgical resection, the pathological findings of the swelling were reported as TB with massive caseous necrosis. According to the World Health Organization diagnostic criteria, the patient was diagnosed with TN-ET, as they met the requirement of four main criteria or the first three main criteria and one secondary criterion. The patient was eventually diagnosed with chest wall TB with TN-ET, which is extremely rare. CONCLUSION: Chest wall TB is rare. TN-ET diagnosis requires secondary factor exclusion and satisfaction of primary diagnostic criteria. miRNA, combined with the methylation process, could explain suppressor of cytokine signaling (SOCS) 1 and SOCS3 downregulation in ET-JAK2V617F-negative patients. The miRNA could participate in JAK2 pathway activation. SOCS3 may be a novel MPN biomarker.