Histoplasmosis mimicking primary lung neoplasm

Abstract

A 70-year-old man, ex-smoker with a 3-pack-year smoking history, presented with a 5-week history of persistent cough. There were no positive findings on clinical examination. The patient's chest X-ray showed a nodular density in the right lung, initially thought to be malignant. After an extensive workup which included CT-guided lung biopsies, bronchoscopies, positron emission tomography scanning, among many other investigations, discussion at the respiratory multidisciplinary team meeting, and a right upper lobe lung resection, a diagnosis of histoplasmosis was performed.

Figure 1

CT taken on 14 June 2011, spiculated right upper lobe lesion.

Figure 2

H&E stain of section from 18 mm lung nodule showing xanthogranulomatous inflamation with foamy macrophages containing multiple intracytoplasmic cysts.

Figure 3

These intracytoplasmic cysts stain positive for Grocott's methenamine silver stain. The morphology is consistent with histoplasmosis.