Histoplasmosis mimicking primary lung cancer or pulmonary metastases.

Objective: To describe the main clinical and radiological characteristics of patients with histoplasmosis mimicking lung cancer.

Methods: This was a retrospective descriptive study based on the analysis of the medical records of the 294 patients diagnosed with histoplasmosis between 1977 and 2011 at the Mycology Laboratory of the Santa Casa Sisters of Mercy Hospital of Porto Alegre in the city of Porto Alegre, Brazil. The diagnosis of histoplasmosis was established by culture, histopathological examination, or immunodiffusion testing (identification of M or H precipitation bands). After identifying the patients with macroscopic lesions, as well as radiological and CT findings consistent with malignancy, we divided the patients into two groups: those with a history of cancer and presenting with lesions mimicking metastases (HC group); and those with no such history but also presenting with lesions mimicking metastases (NHC group).

Results: Of the 294 patients diagnosed with histoplasmosis, 15 had presented with lesions mimicking primary neoplasia or metastases (9 and 6 in the HC and NHC groups, respectively). The age of the patients ranged from 13 to 67 years (median, 44 years). Of the 15 patients, 14 (93%) presented with pulmonary lesions at the time of hospitalization.

Conclusions: The clinical and radiological syndrome of neoplastic disease is not confined to malignancy, and granulomatous infectious diseases must therefore be considered in the differential diagnosis.