Travel Advisory: Fungal granulomatous infections like histoplasmosis and coccidioidomycosis often masquerade as malignancy—specifically, lymphoma or peritoneal carcinomatosis—making travel history and clinical context central to the DDx.
River Valley Giant—In this sample from the “Infection and Its Mimickers in the Abdomen and Pelvis” Online Course, Jonathan W. Revels, DO, reminded us that histoplasmosis is most common in immunocompetent patients.
- Geography: Primarily found in the Ohio and Mississippi River valleys.
- Exposure: Linked to bird or bat droppings.
- Imaging Clues?
- Bilateral adrenal involvement (rare in many other diseases).
- Tiny splenic lesions and hepatosplenomegaly.
- Healed “p-histoplasmosis” often presents as multiple calcified nodules in the spleen, liver, and lymph nodes.
Southwest Passage—Commonly called valley fever, coccidioidomycosis is endemic to the southwestern United States.
- Presentation: Often asymptomatic or presents with flu-like symptoms, but disseminated disease can involve multiple abdominal organs.
- Imaging Clues?
- Peritoneal thickening and enhancement that mimics carcinomatosis or tuberculosis.
- Low-density lymphadenopathy and occasional prostate lesions.
RadFYI: Because the imaging overlap among fungal infections, sarcoidosis, and lymphoma is so significant, more often than not, tissue sampling will be your final differentiator.
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