Case 85. Aspergillosis of lung (49 y-o M)
Surgical specimen of a lung cavity containing a fungus ball
Key words : 
Aspergillus fumigatus, fungus ball, cavity, allergic bronchopulmonary aspergillosis    
opportunistic infection
A thick-walled cavity formed in the upper lobe is associated with fibrotic lung tissue and thickened pleura (gross findings).   Y-shaped, septum-forming basophilic hyphae are arranged in the same direction (HE). Non-viable hyphae show less basophilia.
Septum formation is evident by Grocott's silver. Both viable and dead hyphae are stained well with this method.   Reference case 85A
Otomycosis, presenting conidial heads which produce pigmented spores (HE). The shape of conidiophore and melanin formation are characteristic of Aspergillus niger.
Reference case 85B
Bronchial lavage, presenting Grocott-reactive round spores which are not phagocytized by macrophages. The argyrophilic non-pigmented spores of A. fumigatus should be distinguished from C. neoformans. The latter is usually observed within the phagocyte.
  In situ hybridization for Aspergillus ribosomal RNA
Positive signals are seen at the periphery of the colony, demonstrating the distribution of viable hyphae. RNA hybridization gives us information on the viability of the pathogen.
Reference case 85C
Allergic bronchopulmonary aspergillosis, showing obstruction of the bronchial lumen by eosinophilic exudates with Charcot-Leiden's crystals (HE). Marked eosinophilic infiltration and epithelioid cell reaction in the bronchial wall indicates an allergic mechanism of this rare diseased condition.
  Reference case 85C
Allergic bronchopulmonary aspergillosis, showing short Aspergillus hyphae phagocytized by macrophages in the bronchial wall (Grocott). Infection of hyphae-forming fungi is commonly protected by neutrophils, and usually does not provoke granulomatous reaction. In general, risk of opportunistic infection increases in a neutropenic state. This makes a well contrast to the yeast-form fungi.