Histoplasmosis in cancer patients: a global scoping review (2001-2024)

Although classified as an AIDS-defining illness, several reports show histoplasmosis also affects patients living with cancers including haematological malignancies and solid tumours. However, reviews describing cases of histoplasmosis in malignancies are lacking in the literature. We identified a total of thirty-four cases with twenty (58.8 %) cases reported from the USA, four from Brazil (11.8 %), three from India (8.8 %), and one each from Singapore (2.9 %), France (2.9 %), Netherlands (2.9 %), Colombia (2.9 %), Canada (2.9 %), Morocco (2.9 %), and Malaysia (2.9 %). 82.4 % (n = 28) of the cases were adults. Presenting symptoms were majorly fever (61.7 %), lymphadenopathy (50.0 %) and weight loss (29.4 %). Essential haematologic findings were pancytopaenia (n = 7, 20.6 %), neutropenia (n = 2, 5.9 %) and anaemia (n = 5, 14.7 %). The associated cancers were predominantly haematological and comprised 73.5 % (n = 25) of all cases. The diagnosis of histoplasmosis was via histopathology (n = 23, 67.6%), culture (n = 13, 38.2%), Histoplasma antigen assay (n = 13, 38.2%), anti-Histoplasma antibody assay (n = 5, 14.7%), PCR and sequencing (n = 2, 5.9%), peripheral blood film/direct microscopy (n = 4, 11.8%) and cytology (n = 1, 2.9%). Of the thirty-four cases, twenty-four (70.6%) had favourable outcomes, eight (23.5%) died, one (2.9%) was lost to follow-up and in one (2.9%) case, the outcome was not stated. Histoplasmosis is not an uncommon opportunistic disease complicating malignancies but is paradoxically underdiagnosed in Africa given the huge burden of cancers in that region. Besides following chemotherapy and the use of steroids, tumour necrosis factor-α antagonists therapy, hematopoietic stem cell transplantation and environmental exposure were factors associated with Histoplasma infection in patients with malignancies. A resolution to promptly screen suspected or confirmed cases of malignancies for histoplasmosis will improve diagnosis and clinical outcomes.