We report a 56-year-old male from New Mexico with a 6-month history of weight loss, night sweats, intermittent confusion, and personality changes. He also reports new onset headache and progressive right-sided weakness. His medical history includes alcoholic liver cirrhosis and hypertension. Physical exam demonstrates a well-nourished male in no acute distress, right upper extremity muscle power was 1/5. Initial labs show WBC 6.4×103μL, Hb 11.6 g/dl (normocytic normochromic anemia) and PLT 50 x 03μL. Head MRI with contrast shows multiple ring enhancing lesions with vasogenic edema. HIV, Hepatitis A IgM, Hepatitis BsAg, Hepatitis C antibody, toxoplasma, and leptospira serology were negative. Malignancy work up including chest, abdomen/ pelvis CT , bone scans, protein electrophoresis, tumor markers, bone marrow biopsy, flocytometry, FISH chromosomal analysis were normal. Non-specific lymphadenopathy was noted on the Chest CT scan. Lumbar puncture shows Lymphoplaeocytosis with increased RBCs. CSF gram stain, bacterial antigens, cryptococcal antigen and fungal cultures were negative. A stereotactic right frontal craniotomy was performed and the tissue pathology showed non-caseating granulomatous inflammation with multiple yeasts. Urine test was positive for Histoplasma Capsulatum antigen. Patient was treated with one month of amphotericin with the aim to continue the treatment with voriconazole for a total of 12 months. Repeated MRI after one month of Amphotericin treatment showed improvement of the lesions.
Histoplasmosis is a disease caused by dimorphic fungus called Histoplasma Capsulatum. It has wide spectrum of clinical manifestations. Most patient with histoplasmosis has no symptoms. However when symptomatic, it usually manifests with acute or chronic lung disease. Progressive disseminated disease is rare and almost always occurs in immunosuppressant hosts as in AIDS or patients on Immunosuppression treatment. The disease can be fatal if untreated.
This patient confirmed to have a Histoplasmosis Capsulatum infection by tissue biopsy, he presented with a rare neurological manifestation. Central nervous system ( CNS) involvement is rare as a sole presentation of histoplasmosis. It is almost exclusively manifests as part of disseminated disease and occurs in around 10% of those patients. Our HIV negative patient is considered to have an interesting CNS involvement and has no other evidence of systemic active manifestations. Physicians should maintain high index of suspicion of patients with ring enhanced brain lesions on CT head. Histoplasmosis still should be considered in the differential diagnosis in low risk patients.
To cite this abstract:Mohamed A. Isolated Cns Histoplasmosis in Apparent Immunocompetent Host; Mimicking Brain Metastasis. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 694. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/isolated-cns-histoplasmosis-in-apparent-immunocompetent-host-mimicking-brain-metastasis/. Accessed November 18, 2019.