To the Editors:
Penicillium marneffei was first isolated in 1956 from the liver of the Vietnamese bamboo rat [1]. It is recognised as an emerging infection among HIV-infected patients in South East Asia, where it typically presents as cutaneous lesions, fever, lymphadenopathy and hepatosplenomegaly [2]. Indeed, in this population, it is now the third most common opportunistic infection [3]. Penicilliosis is a rare disease in immunocompetent hosts. It has been previously described in patients with comorbid conditions such as connective tissue diseases and haematological malignancies. Although inhalation of the conidia is thought to lead to disseminated infection, a primary pulmonary presentation is unusual. We describe a unique presentation of systemic P. marneffei infection in an immunocompetent host presenting with an endobronchial tumour-like lesion and post-obstructive pneumonia.
A 45-yr-old, previously well male was referred to our hospital for further investigation of fevers, lymphadenopathy and pulmonary infiltrates. The patient described a 4-month history of intermittent drenching night sweats, cough and posterior cervical lymphadenopathy against a background of a recent bicycle tour of Laos and Vietnam. There was no significant family history, no significant occupational exposure and a trivial smoking history. The patient was initially investigated at a regional hospital with apparently normal chest and abdominal imaging and mild eosinophilia on a peripheral blood film. Excisional biopsy of an enlarged cervical lymph node demonstrated caseating granulomas with no evidence of bacteria or fungi on staining and no clonal proliferation on flow cytometry. Culture for acid-fast bacilli was not requested and the patient was treated with a course of empirical sulfamethoxazole/trimethoprim by a local physician. He eventually re-presented with dry cough, recurrent fevers and left sided pleuritic chest pain. Computed tomography demonstrated resolution of cervical lymphadenopathy but interval development of pulmonary infiltrates and mediastinal lymphadenopathy (fig. 1). Further investigations revealed an elevated C-reactive protein level and a persistent mild peripheral eosinophilia (0.7×109 eosinophils·L−1).
Following referral to our service, the patient underwent fibre-optic bronchoscopy, which demonstrated a large polypoid lesion at the orifice of the lingular lobe (fig. 2).
The lesion was subsequently excised using argon plasma diathermy. Histopathological examination demonstrated caseating granulomas and culture revealed P. marneffei. Bronchoalveolar lavage of the left upper lobe also demonstrated P. marneffei on culture. Culture of the mass lesion and bronchoalveolar lavage was negative for acid-fast bacilli. PCR testing of these samples was also negative for Mycobacterium.
Testing for immune deficiencies demonstrated no evidence of HIV or other blood-borne viruses on serial testing. Peripheral lymphocyte subsets and γ-globulins were within normal limits, and there was no clinical or serological evidence of a connective tissue disease or vasculitis. Neutrophil oxidative burst and phagocytosis function was normal. The patient recorded an indeterminate result in a QuantiFERON®-TB Gold In-Tube test (Cellestis, Chadstone, Australia).
The patient was subsequently admitted for intravenous amphotericin B therapy. During this course of in-patient treatment, the patient developed both pericardial and pleural effusions. These were drained percutaneously, were inflammatory in nature and did not demonstrate Penicillium on culture. The fluid from both sites was also culture negative for acid-fast bacilli. The patient was eventually discharged on oral itraconazole therapy with gradual resolution of symptoms, inflammatory markers and radiological changes.
Infection with P. marneffei was rare prior to the HIV epidemic. However, in South East Asia, it now represents the third most common presenting illness in AIDS sufferers. Penicillium is thermally dimorphic, growing as a mycelium at 25°C and as a yeast at 37°C. Thermal switching enhances its virulence, with the infectious conidia forming from the mycelial state and, once inhaled, switching to the yeast form.
There are very few published data regarding the treatment of penicilliosis in non-HIV-infected patients. Our patient was treated with amphotericin intravenously for 14 days, followed by oral itraconazole. This regimen has been widely used in the treatment of HIV-infected patients and, in our case, led to significant clinical improvement.
Cases of penicilliosis in non-HIV-infected patients are rare. Our review of the literature demonstrated 39 cases of penicilliosis in non-HIV patients (table 1). Notably, the majority of these patients had comorbid conditions affecting immune function or necessitating immunosuppressive treatments. Within the non-HIV population, a primary pulmonary presentation is unusual. There are no cases in the literature that describe the presence of a tumour-like mass and post-obstructive pneumonia.
Footnotes
Statement of Interest
None declared.
- ©ERS 2012