Lan Huang,1– 3 Dongyan Zheng,1– 3 Tiantian Li,1– 3 Xiuying Li,1– 3 Jinliang Kong,4 Ke Wang,4 Shuangjie Wang,5 Cunwei Cao1– 3 

1Department of Dermatology and Venereology, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, People’s Republic of China; 2Guangxi Scientific and Technological Innovation Cooperation Base of Mycosis Prevention and Control, Nanning, 530021, People’s Republic of China; 3Fangchenggang Wanqing Institute of Mycosis Prevention and Control, Fangchenggang, 538000, People’s Republic of China; 4Department of Respiratory and Critical Care, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, People’s Republic of China; 5Department of Clinical Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021, People’s Republic of China

Correspondence: Cunwei Cao, Department of Dermatology and Venereology, the First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning, Guangxi, People’s Republic of China, Email caocunwei@yeah.net

Background: Disseminated histoplasmosis caused by the temperature-dependent dimorphic fungus Histoplasma capsulatum is an invasive fungal disease rarely reported in southern China. Here, we report a case of disseminated histoplasmosis due to anti-IFN–γ autoantibodies (AIGA)- associated immunodeficiency.
Case Presentation: We present the case of a 57-year-old HIV-negative female patient with disseminated histoplasmosis in southern China. The patient showed progressively enlarging multiple clavicular, neck, and upper chest skin nodules and dyspnea, which led to the initial suspicion of pulmonary tuberculosis or lung cancer. Bacterial cultures results were negative. Histopathology of a skin tissue showed infectious granulomas. Disseminated histoplasmosis was diagnosed via next-generation sequencing (mNGS) and fungal culture. Furthermore, enzyme-linked immunosorbent assay results from a peripheral blood confirmed that the patient had a high-titer of AIGA.
Conclusion: This case prompts clinicians to consider histoplasmosis an important differential diagnosis in a region where talaromycosis is highly endemic. This case report emphasizes that clinicians should be vigilant for immunodeficiency and consider testing for AIGA in HIV-negative patients who are suspected of having complex opportunistic infections.

Keywords: Histoplasma capsulatum, anti-interferon-γ autoantibodies, metagenomic next-generation sequencing, a case report