Indolent nonendemic central nervous system histoplasmosis presenting as an isolated intramedullary enhancing spinal cord lesion

Background Histoplasma capsulatum infection is largely seen in endemic regions; it results in symptomatic disease in Case description We present an atypical case of a 44-year-old man from a nonendemic region, on adalimumab therapy for ulcerative colitis who developed an isolated intramedullary spinal cord lesion in the setting of disseminated histoplasmosis. His course was initially indolent with vague systemic symptoms that led to consideration of several other diagnoses including sarcoidosis and lymphoma. Biopsies of several positron emission tomography positive lymph nodes revealed granulomatous inflammation, but no firm diagnosis was achieved. He was ultimately diagnosed with histoplasmosis after an acute respiratory infection in the setting of anti-tumor necrosis factor therapy. With appropriate antifungal therapy, the spinal cord lesion regressed. The previous systemic biopsies were re-reviewed, and rare fungal elements consistent with H. capsulatum were identified. A presumptive diagnosis of CNS histoplasmosis was made in the absence of direct laboratory confirmation in the setting of rapid and complete resolution on antifungal therapy. Conclusion Disseminated histoplasmosis should be considered in granulomatous disease, even if the patient resides in a nonendemic region. Furthermore, clinicians should be mindful that CNS histoplasmosis may present in an atypical fashion.