Rapid postoperative platelet decline in a lung adenocarcinoma with sarcomatoid differentiation and concomitant JAK2 V617F mutation: a case report.

Background: Lung cancer is one of the leading causes of cancer incidence and mortality worldwide. At the molecular level, its development involves aberrations in multiple oncogenic pathways. Here, we report a rare case of lung adenocarcinoma with sarcomatoid differentiation and profound thrombocytosis (1,350 × 109/L), harboring concurrent TP53, JAK2 V617F, and MET exon 14 skipping mutations. Case presentation: A 75-year-old female underwent VATS wedge resection for pathological stage IB lung adenocarcinoma. Platelet counts dropped from 1,350 to 572 × 109/L within 3 weeks postoperatively and remained stable during the 6-month follow-up period. No adjuvant therapy was administered. Molecular profiling of the resected tumor revealed concurrent TP53, JAK2, and MET mutations. Conclusion: This case represents a rare coexistence of JAK2 V617F, MET, and TP53 mutations in lung adenocarcinoma. A marked postoperative decline in platelet count was observed without adjuvant therapy, suggesting a possible tumor-associated reactive thrombocytosis rather than a primary hematologic disorder. Recognition of such platelet dynamics may aid in the clinical assessment and follow-up of lung cancer patients.