Coccidioidomycosis

Coccidiodes immitis

Epidemiology and Etiology:

• Endemic areas:
• Southwest and western US (80% of population have positive skin test)
• Virulence factors:
• Arthroconidia block fusion of phagosome and lysosome, resisting intracellular killing

Common sites:

• Lungs
• Skin
• Disseminated:
• Meninges
• Skin
• Bones
• Adrenals
• Lymph nodes
• Spleen
• Liver

Gross features:

Histologic features:

• arthroconidia (spherules)
• 30-100 microns
• thick walled, refractile
• non-budding
• filled with endospores when mature
• 2-5 microns
• uninucleate
• no budding
• filled with granular contents when immature
• vegetative forms (rare):
• 2-4 micron thick hyphae
• chains of barrel-shaped arthroconidia
• similar to granulomatous lesions of histoplasmosis
• granulomas, usually necrotizing

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• most are asymptomatic
• pulmonary symptoms
• erythema nodosum or erythema multiforme

References:

• Robbins 2005
• Essentials of AP 2006