FIG. 2.

Coccidioides sp.-associated tracheal lesion gross pathology and histology. (A) Portions of trachea, lung, heart, and associated structures. Trachea was opened dorsally revealing in the distal third large, coalescing, firm, tan-brown nodules that in aggregate form an approximately 1–1.5 cm³ luminal mass with partial tracheal obstruction. (B) Cross section through the approximate middle of the tracheal mass revealing that the majority of the mass is ventral to the trachea and was histologically associated with a mostly effaced lymph node. The mass was firm, approximately 2–3 cm³, was mostly tan-brown, and contained moderate amounts of viscous exudate. The white reticulation represents mature and reactive fibrous tissue. The mass protrudes through the tracheal wall and the luminal portion again measures approximately 1 cm wide and extends approximately 6–7 mm dorsally into the tracheal lumen. (C) Hematoxylin and eosin-stained section of formalin-fixed, paraffin-embedded tracheal mass. The section reveals abundant mixed inflammation: neutrophils, lymphocytes, and macrophages. Multiple multinucleated macrophages (“giant cells”) are present, one of which contains a fungal spherule (center of figure) and another that contains a portion of a spherule capsule (upper right of figure). The largest central spherule measures 31 to 33 μm for reference, and contains developing endospores and a thin refractile capsule. More mature spherules (not shown) had numerous endospores approximately 2–5 μm. Size and morphology are diagnostic for Coccidioides sp.