Histoplasmosis mimicking metastatic carcinoma

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From: Journal of Respiratory Diseases(Vol. 29, Issue 9)
Publisher: CMP Medica, LLC
Document Type: Case study
Length: 2,366 words
Lexile Measure: 1450L

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The differential diagnosis for endobronchial lesions includes but is not limited to neoplastic causes, benign tumors, infections, and foreign objects. We report a case of an unusual cause of endobronchial lesions.

The case

A 47-year-old man with a 45-pack-year tobacco history presented to his primary care physician with a 50-lb unintentional weight loss over 3 months, a cough productive of white phlegm, and mouth ulcers. His vital signs were remarkable for the absence of both fever and tachypnea. Physical examination findings were significant for mild cachexia and oral aphthous ulcers.

Laboratory evaluation revealed a normal complete blood cell count but mildly elevated levels of transaminases. A chest radiograph revealed a 2-cm cavitary right upper lobe (RUL) lesion (Figure 1). CT scans of the chest and abdomen revealed the solitary lung lesion, on a background of centrilobular emphysema (Figure 2), and bilateral non-homogeneous adrenal glands, with the left gland appearing larger than the right one (Figure 3). CT scans did not reveal any mediastinal lymphadenopathy or pleural effusions.

Before referral to the pulmonary service, the following workup was performed. Initially, CT-guided fine-needle aspiration of the RUL lesion was performed using a 19-gauge needle. Cytological analysis revealed rare atypical cells, suggesting malignancy. Also, pathology revealed necrotizing granulomas, and stains were negative for fungi and mycobacteria. Two subsequent CT-guided left adrenal core biopsies, using a 19-gauge needle, demonstrated necrotic tissue, debris, and a few yeast forms morphologically suggestive of Candida species.

The patient was referred to otolaryngology for a biopsy of the mouth ulcers. The pathology of the left arytenoid and anterior subglottic region revealed ulcers with acute and chronic inflammation, reactive atypia, and yeast-like organisms. After the patient was referred to the oncology clinic with the presumptive diagnosis of metastatic cancer, CT scans revealed numerous small ring-enhancing cortical brain lesions (Figure 4) and a left main-stem endobronchial mass Figure 5).

On the basis of the chest CT findings, the patient was referred to the pulmonary clinic. The primary team's working diagnosis was metastatic carcinoma; however, our differential diagnosis also included disseminated fungal infection and, less likely, tuberculosis and respiratory papillomatosis. Fungal infection was thought to be less likely after the results of a urinary antigen test for Histoplasma capsulatum, an HIV test, and routine and fungal sputum cultures were reported as negative.

Diagnostic bronchoscopy revealed numerous polypoid lesions lining the trachea and bilateral main-stem bronchi. The lesions were of various sizes, from several millimeters to more than a centimeter in diameter, and were smooth without visible vessels or ulceration (Figure 6). The tracheal lesions were identical in appearance to the polypoid lesions in the main-stem bronchi.

Endobronchial biopsy and bronchoalveolar lavage (BAL) were performed. Cytological analysis of the BAL fluid revealed alveolar macrophages with intracellular yeast forms (Figure 7). The biopsy results revealed multiple small fungal forms with narrow-based budding on silver stain (Figure 8).

After the cytological results were received, the diagnosis of H capsulatum infection was confirmed by bronchoscopy culture results. The patient was admitted and was given amphotericin B...

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Gale Document Number: GALE|A188424333