Pulmonary Blastomycosis Masquerading as Metastatic Disease in the Lung: A Case Report

Bobbak Vahid, MD; Bernadette Wildemore, MD; Christopher Nguyen, MD; Niki Sistrun, MD; Paul E. Marik, MD

Disclosures

January 31, 2006

Case Report

We report a case of a 67-year-old man with a history of smoking who presented to our hospital for treatment of laryngeal carcinoma that was diagnosed several months earlier at another institution. The patient had initially declined treatment but decided to seek therapy because of increased cough, hoarseness, and weight loss. On presentation, he denied fever, night sweats, hemoptysis, or dysphagia. He was afebrile with a blood pressure of 136/68 mm Hg, a heart rate of 68 beats per minute, and a respiratory rate of 16 breaths per minute. His physical examination was unremarkable and revealed no cervical or supraclavicular lymphadenopathy, no cyanosis or clubbing, and no skin lesions. Direct laryngoscopy showed a large laryngeal mass that was biopsied and diagnosed as an invasive, moderately differentiated keratinizing squamous cell carcinoma with evidence of perineural involvement. Evaluation of the airways with flexible bronchoscopy showed no endobronchial lesions, and esophagoscopy showed a normal esophagus. The patient's initial PET scan showed increased activity in the larynx and cervical lymph nodes but no evidence of distant metastasis. Subsequently, the patient underwent total laryngectomy with bilateral modified neck dissection. Pathologic examination of the specimen showed a well-differentiated to moderately differentiated keratinizing squamous cell carcinoma involving the supraglottis, glottis, and subglottis, with invasion into the preepiglottic space and through the thyroid cartilage into the left lobe of the thyroid. Three out of 10 lymph nodes were involved with metastatic squamous cell carcinoma. About a month after surgery, a follow-up PET scan was performed to search for residual disease in the neck and revealed increased activity immediately superior and to the left of the tracheostomy site that was suspicious for residual disease. The follow-up PET scan also showed subpleural activity with a standard uptake value (SUV) of 3.4 in the right lower lobe of the lung that was compatible with metastatic disease in the lung (Figure 1A).

A CT scan of the chest showed a subpleural soft-tissue density mass with spiculated margins in the right lower lobe (Figure 1B). CT-guided fine-needle aspiration of the lesion was performed. Cytologic examination of the aspirate cell block revealed scant granulomatous material with scattered large, spherical cells that resembled yeast. The organisms were best seen on the aspirate smear with the Papanicolaou stain. With this stain, the fungi were noted to be thick-walled and doubly refractile. In addition, some of these cells showed a single bud connected to the parent cell by a distinct broad base (Figure 2).

(A) Coronal (left) and transaxial (right) 18F-fluoro-2-deoxy-D-glucose positron emission tomographic images demonstrating the primary laryngeal tumor (long arrow) and the focus of blastomycosis (short arrows). (B) Computed tomographic scan of the chest showing a soft-tissue density mass in the right lower lobe (arrow).

(A) Coronal (left) and transaxial (right) 18F-fluoro-2-deoxy-D-glucose positron emission tomographic images demonstrating the primary laryngeal tumor (long arrow) and the focus of blastomycosis (short arrows). (B) Computed tomographic scan of the chest showing a soft-tissue density mass in the right lower lobe (arrow).

Thick-walled, doubly refractile yeast cells showing broad-based budding characteristic of Blastomyces dermatitidis (Papanicolaou stain, 1000X).

Based on this characteristic histopathologic appearance, the specimen was reported as most consistent with blastomycosis.

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