Right lung cavitation: Don’t forget coccidioidomycosis – A case report

Introduction

In clinical practice, the aetiology of pulmonary cavities requires consideration not only of common causes such as lung cancer and tuberculosis but also of rare causes. Pulmonary coccidioidomycosis is caused by infection with the Coccidioides species. Coccidioides is predominantly prevalent in regions such as California and Arizona in the United States ¹ and is rare in other parts of the world. Patients commonly present with symptoms including cough, sputum production, and fever; in severe cases, pulmonary opacities and cavitation may develop. ² We recently admitted a patient with pulmonary coccidioidomycosis, the details of which are presented below.

Case presentation

A 65-year-old female patient presented with fever for the first 3 days (exact temperature unknown) 4 months prior to admission to our hospital. She had no dizziness, headache, haemoptysis, night sweats, chest tightness, dyspnoea, chest pain, palpitations, nausea, vomiting, abdominal pain, or diarrhoea. She gradually developed a cough with white sputum. No medical consultation or treatment was sought. The cough recurred intermittently. The patient consulted a local hospital, where a chest CT scan revealed right lower lobe opacity with cavitation 1 month prior to admission. She was treated with moxifloxacin for 2 weeks. Cryptococcal capsular polysaccharide test was negative. The patient continues to experience paroxysmal coughing without fever, chest tightness, or dyspnoea. She presented to our outpatient clinic. Chest CT showed right lower lung lesion with cavitation, surrounded by patchy and speckled areas of increased density (Figure 1). Admission was recommended for further diagnosis and treatment.

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Figure 1.

Chest CT: right lower lung lesion with cavitation, surrounded by patchy and speckled areas of increased density.

The history of essential hypertension was managed with irbesartan 0.15 g QD orally. The patient denied a history of diabetes mellitus; history of cerebrovascular, hepatic, renal, or endocrine disorders; infectious diseases; surgery, trauma, poisoning, or blood transfusions; food or drug allergies. Immunisation history was unknown.

Physical examination: Temperature 36.7 °C, pulse 97 beats/min, respiration 20 breaths/min, BP 143/72 mmHg, and SPO₂ 99%. The patient was alert and oriented, with good mental status. She had bilateral pupils with brisk pupillary light reflexes, and no cyanosis of lips. Pharynx was without hyperaemia, tonsils were not enlarged, neck was soft, no palpable enlarged superficial lymph nodes were noted. No significant rales were heard in both lungs, heart rate was 97 beats/min, and regular rhythm was noted. Abdomen was soft with no tenderness or rebound tenderness. Liver and spleen were not palpable below the costal margin, there was negative for shifting dullness, there was no oedema in both lower limbs, and there were negative Babinski signs bilaterally.

Preliminary diagnosis: (1) Right lower pulmonary opacity with cavitation (infectious lesion primarily considered) and (2) hypertension grade 1 (low risk).

Upon admission, treatment was administered to alleviate symptoms, including cough suppression and expectoration. Further examinations were completed: contrast-enhanced chest and abdominal CT showed a right lower lobe lesion with local cavitation, and an infectious lesion was primarily considered. A fibrotic lesion was seen in the right middle lobe, a hepatic cyst was noted, and an ascending colon lipoma was seen. Tuberculosis infection T-cell testing is negative. IgE was normal. Tubercle bacillus smear showed no acid-fast bacilli. Antinuclear antibody was negative. High-sensitivity C-reactive protein, procalcitonin quantitative, complete blood count, liver function, kidney function, glycated haemoglobin, random blood sugar, HIV, D-dimer, thyroid function, and tumour markers were all normal. Bronchoscopy showed bilateral bronchi patent. An ultrasound probe was inserted into the right lower lobe lateral basal bronchus. After locating the lesion, the probe was withdrawn. Transbronchial lung biopsy, brush sampling, and alveolar lavage were performed. There was a negative Xpert MTB and Xpert RIF-R result from bronchoscopic lavage fluid. Mycobacterial smear showed no acid-fast bacilli, and galactomannan (GM) assay was 0.04.

Further medical history inquiry revealed that the patient had resided briefly with his son in California, USA, 4 months prior. Subsequently, a CT-guided percutaneous lung biopsy was performed (Figure 2). Lung biopsy findings (right lower lobe biopsy) showed granulomatous inflammation with necrosis in lung tissue, suggestive of an infectious lesion, with visible spherical spores and endospores (Figure 3). Immunohistochemistry results showed CK (+) in alveolar epithelium; TTF-1 (+) in alveolar epithelium; Napsin A (+) in alveolar epithelium; P63 (−); CK5/6 (−); CD68 (+) in histiocytes; P40 (−); acid-fast staining (−); hexamine silver staining (−); PAS staining (−). Right lung biopsy smear showed scattered histiocytes, lymphocytes, etc., with no definitive evidence of malignancy. Next-generation sequencing (NGS) results from bronchoalveolar lavage fluid showed Coccidioides (Coccidioides posadasii; Table 1).

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Figure 2.

Percutaneous lung biopsy under CT guidance.

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Figure 3.

Granulomatous inflammation with necrosis in lung tissue, showing spherical spores and endospores.

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Table 1.

NGS results from bronchoalveolar lavage fluid, suggestive of coccidioidomycosis.

Genus			Species
Genus	Relative abundance	Sequence count	Species	Confidence of identification	Sequence count
Coccidioides	26.0%	101	Coccidioides posadasii	99%	30

NGS: next-generation sequencing.

Discharge medication: Fluconazole tablets 400 mg once daily for 4 weeks.

Discharge diagnosis: (1) Right lower lung opacity with cavitation (Pneumocystis pneumonia). (2) Hypertension, stage 1 (low risk).

Follow-up: After 6 months, CT revealed a significant reduction in the lung lesion cavity, with no obvious symptoms such as cough in the patient (Figure 4).

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Figure 4.

CT revealed a significant reduction in the lung lesion cavity after 6 months.

Discussion

This elderly female patient presented with no underlying immunodeficiency or metabolic disorders, exhibiting a chronic course characterised primarily by a persistent cough. She had a history of fever, with negative results for infection markers, tumour markers, immunological indicators, tuberculosis, and other relevant tests. Chest CT revealed right lower lobe lesions with cavitation, featuring regular cavity walls and perilesional exudative shadows. Moxifloxacin demonstrated inadequate anti-infective efficacy. Diagnosis remains challenging, necessitating differential considerations: (I) Infectious diseases: (1) bacterial infections: common pathogens in community-acquired pneumonia include Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens. Given the patient’s recurrent cough, prolonged course, normal WBC, CRP, and PCT levels, and poor response to moxifloxacin, common bacterial or atypical infections appear unlikely. The patient’s T-cell test for tuberculosis infection was negative, and no sputum was found to indicate TB. Evidence for tuberculosis is currently insufficient. (2) Fungal infection: the patient’s chest CT scan shows a right lower lung lesion with cavitation, accompanied by a small amount of ground-glass opacity. Fungal infections such as cryptococcosis should be considered, but the patient has no risk factors for fungal infection (such as immunosuppression). Further differentiation requires cryptococcal capsular tests, G tests, and GM tests. (3) Viral infection: viral pneumonia may present clinically with fever, cough with sputum production, and elevated inflammatory markers. Pulmonary imaging typically shows bilateral involvement with ground-glass or interstitial changes. Given the patient’s recurrent cough with sputum production over a 4-month course and atypical chest CT findings, this is provisionally excluded. (II) Non-infectious diseases: (1) lung cancer: it may present with dry cough, blood-streaked sputum, and weight loss. Chest CT commonly reveals lobulation, spiculation, or pleural retraction. Her post-admission tumour markers were within normal range; no spiculation or pleural retraction was observed. Cavity walls were regular with no evidence of malignant cavitation, suggesting a low likelihood of malignancy. (2) Granulomatous polyangiitis: it may present with multiple pulmonary nodules and cavities alongside renal involvement, but ANCA was negative; therefore, it was provisionally excluded. Given the patient’s confirmed history of residence in California (an endemic region), combined with histopathology and NGS results from bronchoalveolar lavage fluid, the diagnosis is pulmonary coccidioidomycosis.

Coccidioidomycosis is an endemic fungal disease prevalent in the western United States, including the Central Valley of California, Arizona, and New Mexico. ³ Pulmonary lesions are more commonly observed in coccidioidomycosis, whereas pulmonary coccidioidomycosis is rare in China. ⁴ No case of coccidioidomycosis has been reported and recorded in our country in the last 5 years. Disturbing soil causes Coccidioides hyphae to break apart, releasing spores into the air. When a person inhales these spores, they can settle in the lungs and develop into spherules. Risk factors for acquiring coccidioidomycosis include travel to or residence in endemic areas, exposure to dirt or dust, diabetes mellitus, third-trimester pregnancy, and a weakened immune system. Integrating literature, key diagnostic, and therapeutic considerations for pulmonary coccidioidomycosis are summarised.^5–10: (1) Mycological characteristics: Coccidioides is a dimorphic fungus whose hyphae can form spores that become pathogenic upon pulmonary inhalation. (2) Diagnosis: coccidioidomycosis is diagnosed through microbiological culture, histopathological biopsy analysis, or serological testing. Pulmonary coccidioidomycosis can be diagnosed by direct microscopic observation (in bronchoalveolar lavage fluid or tissue biopsy) of isolated Coccidioides species and mature endosporangia. (3) Classification is based on clinical and imaging findings: pulmonary coccidioidomycosis is categorised into acute, disseminated, and chronic forms. (1) Acute: it is also termed as primary Coccidioides infection. Following a 7- to 21-day incubation period, patients may present with mild influenza-like symptoms progressing to acute pneumonia. The most common symptoms are cough, fever, headache, and chest pain. Patients may experience night sweats and persistent fatigue. (2) Disseminated: it is less common, affecting any organ system. Frequently involved sites include the skin and central nervous system (e.g. meninges). This form typically progresses acutely; delayed diagnosis and treatment may lead to rapid mortality. (3) Chronic: persistent pulmonary lesions with progressive deterioration manifesting as persistent low-grade fever, cough, anorexia, and weight loss, with some patients experiencing haemoptysis, occurring more than 8 weeks after primary infection. The course is slow and prolonged, lasting from months to years. Treatment: (1) patients with pulmonary nodules or cavities due to asymptomatic Cryptococcus infection without immunosuppression may forgo antifungal therapy. (2) For symptomatic pulmonary coccidioidomycosis, oral fluconazole or itraconazole is recommended. (3) Surgical intervention may be considered for patients with persistent significant haemoptysis or recurrent symptoms after standard anti-Coccidioides therapy, or those with persistent pulmonary lesions exceeding 2 years post-treatment cessation. This patient was administered fluconazole tablets 400 mg once daily orally, with cough symptoms gradually improving post-treatment. This case provides clinicians with an important diagnostic approach and therapeutic reference.

Conclusion

This patient presented with a cavitary pulmonary lesion, ultimately diagnosed as pulmonary coccidioidomycosis following comprehensive investigations. Symptomatic treatment led to clinical improvement. For patients presenting with pulmonary opacities with cavitation, beyond common aetiologies such as lung cancer or tuberculosis, consideration should extend to less frequent causes, including fungal infections like coccidioidomycosis, particularly in individuals with relevant travel history to endemic regions.