A Hidden Diagnosis: Disseminated Histoplasmosis Mimicking Tuberculosis in the Elderly
https://doi.org/10.15605/jafes.041.S1
- Author:
Wan Muhamad Amir Wan Md Zin
1
;
Moon Yan Yap
1
;
Meroshini Sundaran
1
;
Siti Nabilah ‘Atiqah Othman
1
;
Siti Nabihah Mohamed Hatta
1
;
Maz Anirah Abdul Azis
1
Author Information
1. Department of Medicine, Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia
- Publication Type:Journal Article
- MeSH:
Adrenal incidentaloma;
Lung Neoplasms
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):28-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Histoplasmosis is a rare opportunistic, inhalation-acquired
systemic mycosis caused by Histoplasma capsulatum,
endemic to Southeast Asia, including Malaysia. Although
classically seen in immunocompromised hosts, it is
increasingly reported in immunocompetent individuals.
Infection is associated with environmental exposures such
as bat or bird droppings and soil disruption. Histoplasmosis
is a progressive granulomatous disease that can closely
mimic tuberculosis and malignancy, making diagnosis
challenging.
Case:An 87-year-old Malay male with a history of treated
pulmonary tuberculosis presented with a 6-month history
of intermittent fever, anorexia, weight loss, and hypotension. Initial computed tomography imaging demonstrated bilateral heterogeneous adrenal masses (right: 2.2
× 3.7 × 5.0 cm; left: 2.0 × 3.7 × 5.2 cm) with indeterminate
washout characteristics. Biochemical adrenal evaluation,
including a short Synacthen test, confirmed primary
adrenal insufficiency. Extensive microbiological and
malignancy workup, including bronchoscopy, cultures,
and tumor markers, was non-diagnostic. In view of clinical
deterioration and epidemiological risk, empirical antituberculous therapy was initiated; however, no clinical
improvement was observed after 2 months. PET-FDG revealed intensely hypermetabolic bilateral adrenal masses
(SUVmax right 16.7, left 13.2) with no other abnormal
foci. Non-invasive fungal investigations were negative.
Definitive diagnosis was established via computed
tomography-guided adrenal biopsy, which demonstrated
necrotizing granulomatous inflammation with intracellular
yeasts, subsequently identified as H. capsulatum. The patient
was treated with oral itraconazole and corticosteroid
replacement, resulting in significant clinical improvement
and planned interval radiological reassessment.
Conclusion:Disseminated histoplasmosis is a diagnostic challenge,
particularly in frail elderly patients, where invasive
procedures may be delayed. It can mimic tuberculosis
and malignancy and may lack an identifiable exposure
history. Non-invasive tests may be inconclusive, making
tissue biopsy essential. Adrenal involvement may result
in primary adrenal insufficiency, further complicating
the clinical picture. Early consideration and timely
confirmation are crucial for appropriate management.
- Full text:2026072814001737741EP_A018.pdf
