Case 175. Penicilliosis marneffei of skin in AIDS (35 y-o F)
         
   
Skin biopsy with disseminated penicilliosis marneffei in a Thai AIDS patient
   
         
   
Key words : Penicillium marneffei, AIDS
   
         
   
opportunistic infection
   
     
 
     
Numerous rounded, basophilic microbes are seen in the cytoplasm of macrophages. Clusters of pathogens are also seen among the squamous epithelium (HE).   Oil immersion observation discloses nucleated basophilic granules in the cytoplasm of macrophages (HE). Compare the size of microbes with mast cell granules.
     
 
     
Lymph node biopsy from the same patient of lethal penicilliosis marneffei
Yeast-form fungi are massively phagocytized by macrophages (HE). Penicillium marneffei solely shows the yeast form in the human body. Disseminated yeasts are mostly seen in the cytoplasm of macrophages.
  Lymph node biopsy from the same patient of lethal penicilliosis marneffei
Yeast-form fungi filling the cytoplasm of macrophages are PAS-reactive. Protozoan parasites such as Leishmania and Trypanosoma can be distinduished by PAS and Grocott stains. The protozoa is negative wiil PAS and Grocott stains.
     
 
     
Lymph node biopsy from the same patient of lethal penicilliosis marneffei
Grocott's silver identifies pathognomonic septum formation (schizogony). Recognition of the septa in the yeasts is essential to make a definite diagnosis. The other yeast-form fungi, including Histoplasma capsulatum, show budding features for cell divisions.
  The splenic lesion from the same patient, obtained by necropsy
Grocott's silver demonstrates formation of short myceliform fungi within the cytoplasm of macrophages. Rarely, short mycelial form fungi can be seen in the internal organs. P. marneffei is the only one Penicillium species to cause deep mycosis in immunocompromised individuals such as AIDS patients, and is endemic in southeastern Asia, particularly in Thailand.