[Disseminated histoplamosis in adolescent mimicking granulomatosis with polyangiitis].

INTRODUCTION: Systemic histoplasmosis is an invasive fungal infection that may mimic primary vasculitis, particularly granulomatosis with polyangiitis (GPA), and was rarely described in adult patients. We reported an immunocompetent patient with disseminated histoplasmosis mimicking GPA who fulfilled European League Against Rheumatism (EULAR)/Pediatric Rheumatology International Trials Organisation (PRINTO)/Pediatric Rheumatology European Society (PRES) validated classification criteria.

CASE REPORT: A 6-year old boy presented acute migratory polyarthritis with spontaneous improvement, sinus inflammation, fever, headache and abdominal pain. Serologic test for hepatitis, cytomegalovirus, human immunodeficiency virus, Epstein-Barr virus, toxoplasmosis, dengue virus and antistreptolysin O were all negative. Magnetic resonance imaging (MRI) showed moderate ascites in pelvis and pansinusitis. Antineutrophil cytoplasmic antibodies (c-ANCA) were positive. He had spontaneous remission of the symptoms including fever. At the age of 11 years and 11 months, he had sinusitis, pneumonia and epididymitis. A month later, he was hospitalized and MRI showed left eye proptosis. Cerebrospinal fluid was normal and indirect tests of fungi were negative. Two months later, he had lumbar pain and computer tomography showed a mass in the right kidney and pulmonary nodule in the right lung. He fulfilled EULAR/PRINTO/PRES criteria for GPA, however the renal biopsy showed a focal granulomatous interstitial nephritis with yeast fungal cells compatible with Histoplasma sp. He was treated with liposomal amphotericin B and itraconazole with improvement of signs and symptoms.

CONCLUSION: We reported a progressive disseminated histoplasmosis case mimicking GPA. Histoplasmosis infection should be considered in immunocompetent subjects with uncommon clinical manifestations, such as arthritis, nephritis and epididymitis.