A 42-year-old male patient visited the emergency room of our hospital in November 2013 with fever, sore throat, and diarrhea. He was a known seropositive patient for HIV and syphilis and a frequent traveler to Guangxi, China, and Hong Kong. Laboratory testing on admission showed a white blood cell count of 9600/muo (8764/muh, neutrophils, 470/muh lymphocytes), 7.0 g/dL hemoglobin, and 86 K/muh platelets. The peripheral CD4+ T lymphocyte count was 25 cells/mup. Computed tomography (CT) scans revealed bilateral septal thickening and micronodules of both the lungs, severe hepatosplenomegaly, and multiple enlarged lymph nodes in the chest and abdominal cavity, with tuberculosis or malignancy, especially lymphoma, suspected. Bronchoscopy revealed multiple micronodules in the wall of the right bronchi. Bronchoscopic biopsy and washing cytology with concurrent supraclavicular lymph node biopsy were performed.
The bronchial washing cytology was diffuse and cellular smear contained mixed inflammatory infiltrate, including numerous histiocytes, lymphocytes, some eosinophils, and neutrophils. Most histiocytes were packed with many yeast-like organisms measuring 3mm in diameter that stained dark brown on methenamine silver (GMS) stain [Figure 1]. Focusing up and down through histiocytes, the organisms appeared to have a central dot-like structure. Bronchoscopic biopsy revealed anergic tissue reactions with histiocytic infiltration. In Hematoxylin and eosin (H and E)-stained sections, the organisms were seen as nonbudding round-to-oval spherules within the histiocytes in the submucosa of bronchi [Figure 2]. These organisms were also observed extracellularly but not in bronchial epithelial cells. In the lymph node, there was lymphoid depletion with diffuse proliferation of histiocytes engorged with many organisms.
On the basis of cytologic and histologic findings, the initial cytopathologic interpretation suggested histoplasmosis. Two days after admission, the mycelial form presented in an interim report on a fungal culture obtained from the blood. Given its dimorphic feature and the patient's history of travel to endemic areas, penicilliosis was suspected and a polymerase chain reaction assay was positive for P. marneffei. We reviewed the bronchial washing and biopsy findings. In the cytologic specimen, while intracellular organisms appeared to be uniform yeasts of 3 mus in size, extracellular fungi were elongated and up to 8 mui in length (sausage form). The most characteristic feature was a central transverse septum that was transparent with Papanicolaou stain but highlighted by GMS stain [Figure 1]. The size, shape, and distribution of the organisms were similar in both biopsy and cytologic specimens, except that central dots and septa were more readily identified on cytologic smears.
After amphotericin B administration, the patient exhibited clinical and radiologic improvement. Amphotericin B was changed to oral itraconazole 400 mg/day after 2 weeks. Toxoplasma IgG, influenza, and pneumococcal-conjugated (PCV 13) vaccines were also prescribed to prevent opportunistic infections. The patient continues to visit the outpatient clinic without any specific problems.