BACKGROUND Chronic myelomonocytic leukemia (CMML), a rare clonal hematopoietic stem cell disorder characterized by myelodysplastic syndrome and myeloproliferative neoplasms, has a generally poor prognosis, and easily progresses to acute myeloid leukemia. The simultaneous incidence of hematologic malignancies and solid tumors is extremely low, and CMML coinciding with lung malignancies is even rarer. Here, we report a case of CMML, with ASXL1 and EZH2 gene mutations, combined with non-small cell lung cancer (lung squamous cell carcinoma). CASE SUMMARY A 63-year-old male, suffering from toothache accompanied by coughing, sputum, and bloody sputum for three months, was given a blood test after experiencing continuous bleeding resulting from a tooth extraction at a local hospital. Based on morphological results, the patient was diagnosed with CMML and bronchoscopy was performed in situ to confirm the diagnosis of squamous cell carcinoma in the lower lobe of the lung. After receiving azacitidine, programmed cell death protein 1, and platinum-based chemotherapy drugs, the patient developed severe myelosuppression and eventually fatal leukocyte stasis and dyspnea. CONCLUSION During the treatment and observation of CMML and be vigilant of the growth of multiple primary malignant tumors.

BACKGROUND The development of peripheral T-cell lymphoma (PTCL) after chemotherapy for Hodgkin’s lymphoma (HL) is rare, and highly aggressive TCL/leukemia has not been reported to date. The relationship between HL and PTCL needs further exploration to understand the pathogenesis of metachronous lymphoma (ML) and find effective treatment options. We report a patient with ML, whose biopsy of a right cervical lymph node initially confirmed classical HL (CHL). CASE SUMMARY We report a patient with ML, whose biopsy of a right cervical lymph node initially confirmed CHL, with typical reed–sternberg cells expressing CD30 and PAX-5. T-cell leukemia/lymphoma occurred 3 years after treatment, and a lymph node biopsy at the onset confirmed PTCL, nonspecific type, expressing CD3, CD4 and CD8. The patient was treated with standard doses of chemotherapy, programmed cell death-ligand 1 monoclonal antibody, and chidamide, all of which failed to achieve complete remission. The patient was diagnosed with refractory state, and eventually died of leukocyte stasis. CONCLUSION The accuracy of the diagnosis needs to be confirmed when chemotherapeutic drugs are not effective.