Fungal Infection Can Mimic Lung Cancer Metastases

A fungal infection typically seen in the lungs may have a variety of unusual clinical presentations elsewhere in the body, even raising suspicion of cancer in some cases, a medical resident reported at the annual meeting of the American College of Chest Physicians.

In one recent and unusual presentation, a 58-year-old woman with persistent headaches had skull lesions on computed tomography (CT) was eventually diagnosed with disseminated coccidioidomycosis (Valley fever), a fungal infection endemic to the Southwestern U.S.

The imaging pattern of her head CT was initially concerning for cancer metastasis, according to Sharjeel Israr, MD, a third-year internal medicine resident at Creighton University in Phoenix, Ariz.

However, the subsequent chest CT revealed a suspicious chest mass. A biopsy of that mass led to the correct diagnosis of disseminated coccidioidomycosis, according to Israr, who presented the case report in an e-poster at the CHEST meeting, which was held virtually this year.

Mistaken Identity

Coccidioidomycosis, caused by the fungus Coccidioides, usually affects the lungs, according to the Centers for Disease Control and Prevention. However, in severe cases it can spread to other parts of the body. In those cases, it's referred to as disseminated coccidioidomycosis.

Arizona accounted for about 10,000 out of 18,000 reported Valley fever cases in 2019, according to the latest statistics from the CDC.

Coccidioidomycosis is frequently mistaken not only for cancer, but also for rheumatic conditions and bacterial infections, according to Valley fever specialist John Galgiani, MD, director of the Valley Fever Center for Excellence at the University of Arizona in Tucson.

"Where Valley fever is common, it should very frequently be in the differential for masses that are thought to be cancer," Galgiani said in an interview. "This case is a good example of that."

Challenging Case

In an interview, Israr said the case was challenging to crack despite the fact that Valley fever is very common in Phoenix.

"It was definitely on the differential from the get-go, but it was very, very low our differential, just based on the presentation that she had," said Israr.

The patient had history of diabetes and presented with headaches for 4 weeks. However, she had no pulmonary symptoms or meningeal signs, according to Israr.

A head CT revealed multiple osseous skull lesions and a left temporal lobe lesion.

"The fact that this patient had lesions in the skull, specifically, is something that raised our initial red flags for cancer – especially since she presented with just a headache as her only complaint," he said.

The imaging pattern was concerning for metastasis, according to Israr, particularly since a subsequent CT of the chest showed multiple pulmonary nodules plus a 7.7-cm mass in the right lower lobe.

Once the biopsy confirmed coccidioidomycosis, the patient was started on fluconazole 600 mg twice daily, according to Israr.

Although severe disseminated coccidioidomycosis can be difficult to treat, the lung lesion had decreased in size from 7.7 cm to 4.2 cm about 3 months later, Israr said.

"At the end of the day, she didn't have cancer, and it's something that we're treating and she's actually doing better right now," Israr said in the interview.

Israr and coauthors of the case reported they had no relevant relationships to disclose.

This article originally appeared in Chest Physician.

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Cite this: Fungal Infection Can Mimic Lung Cancer Metastases - Medscape - Oct 25, 2021.