Background Talaromyces marneffei is an invasive, and thermal dimorphic pathogenic fungus, whose infection is life threatening in human . Although immunocompromised patients, such as patients with human immunodeficiency virus infection and recipients of organ transplant, are susceptible hosts, infections have been recently reported in people with normal immune function. Patients with cancer may also be susceptible hosts but no case of T. marneffei infection has been reported in patients with lung cancer. In this case, we describe T. marneffei infection coexisting with primary pulmonary lymphoepithelioma-like carcinoma (LELC) in an HIV-negative patient. Case presentation A 50-year-old, previously healthy female presented with a 1-month history of cough and fever. CT scans showed a mass in the left lower lung, left pleural thickening, pleural effusion, and multiple swollen lymph nodes throughout the body. Based on the pathology of the left lung lesion, she was diagnosed with left primary pulmonary LELC complicated with T. marneffei . She received both anti-tumor and anti-fungal treatments. A subsequent CT re-examination demonstrated that the mass was absorbed remarkably after treatment. Follow up showed no tumor progression and no relapse of T. marneffei infection. Conclusion This case suggested that clinicians should pay more attention to the potential hosts of T. marneffei infection, especially those with lung cancer. Early diagnosis and treatment can improve the prognosis of T. marneffei infection coexisting with lung cancer.

Background Talaromyces marneffei is considered to commonly cause infection in individuals with human immunodeficiency virus (HIV) infection. However, the epidemiology of T. marneffei has changed, and an increasing number of HIV-negative but immunodeficient patients are infected with T. marneffei . The mechanisms of T. marneffei infection of HIV-negative hosts are complex and diverse. We report 2 cases of HIV-negative lung cancer with T. marneffei infection and positive anti-interferon-gamma autoantibodies (AIGAs) to provide clinical experience. Case Presentation We report lung adenocarcinoma combined with T. marneffei infection in HIV-negative patients, and their AIGAs were measured. Both patients were male with a family history of cancer and presented with recurrent fever and cough. The patients were negative for HIV antibodies but positive for AIGAs. Chest computed tomography (CT) showed pulmonary nodules, exudative lesions and solid changes. The patients were diagnosed with lung adenocarcinoma and Talaromycosis marneffei (TSM) by pathological examination and tissue culture. Patient 1 received only antifungal treatment, refused antitumor treatment and died in February 2019, and Patient 2 unfortunately died in April 2019 after antifungal and antitumor treatments. Conclusion An increasing number of HIV-negative but immunodeficient patients are infected with T. marneffei . The 2 patients in this report had lung cancer and positive AIGAs, causing immunodeficiencies, but the mechanism of T. marneffei infection in such patients is complex. Clinically, we should consider a comprehensive immunological examination to avoid the omission of other immunodeficiencies. We recommend routine testing for AIGA levels in HIV-negative marneffei patients. It is difficult to distinguish between lung cancer and disseminated TSM due to similar clinical characteristics and imaging, and multiple biopsies and cultures of diseased tissue are necessary. Early antifungal treatment and standard antitumor treatment can achieve satisfactory curative effects when a patient has both diseases.