We present here what may be the first reported case of Histoplasma tenosynovitis in a patient treated with a tumor necrosis factor (TNF) blocker.
A 50-year-old woman with a history of Takayasu arteritis (since age 33) and ulcerative colitis (age 47) presented with 4 weeks of pain and swelling of the palmar aspect of the right hand and wrist (Figure 1A). Six weeks earlier, she had received a glucocorticoid injection into the right carpal tunnel in response to tingling of the fingers. Immunosuppressive medications included a stable regimen of infliximab, methotrexate, and low-dose prednisone.
C-reactive protein and white blood cell count were normal. Serology panel for endemic fungi (by complement fixation to yeast and mycelial phases) and Histoplasma urine antigen were negative, as were fungal, mycobacterial, and routine blood cultures. In the operating room, the patient was found to have tenosynovitis of essentially all flexor tendons of the distal forearm, wrist, and proximal hand, albeit without frank purulence. Crystal examination was negative. Histopathology revealed non-necrotizing granulomatous inflammation.
In this patient, the differential diagnosis included infection with indolent bacteria (Nocardia, Coxiella, Bartonella), mycobacteria, Candida (given recent injection), endemic fungi (Histoplasma or Sporothrix), and other molds (Aspergillus). Inflammatory bowel disease–associated arthritis and sarcoidosis were also considered. After 14 days, the fungal culture (surgical specimen) grew an organism (Figure 1B). Itraconazole was initiated the same day.
Histoplasma is a rare cause of tenosynovitis1. To our knowledge, this is the first reported case in a patient treated with a TNF blocker. Histoplasma urine antigen is positive in 90% of cases of disseminated histoplasmosis2, including those receiving TNF blockers3; however, the sensitivity of this test in the context of localized, extrapulmonary infection has not been established. In this case, the correct diagnosis was only revealed upon fungal culture of the surgical specimen.
Footnotes
RJW was supported by the US National Institutes of Health (NIH) K08AI119182. JSK was supported by NIH K08AR066569 and career development awards from the Burroughs Wellcome Fund, the Rheumatology Research Foundation, and the Arthritis National Research Foundation.
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