The widened alveolar walls here are covered by hypertrophied type II cells except at the arrow, where there is necrosis with an exudate of PMNs and a few RBCs spilling into the alveoli. This lesion is a capillaritis.

Capillaritis was probably not clinically significant in this patient as dyspnea was mild, and he had no fall in hematocrit or widespread ground-glass opacities on HRCT. The lesion is probably a manifestation of his angiitis at the capillary level.

An iron stain of the same section seen here shows increased numbers of hemosiderin-filled macrophages indicating old alveolar hemorrhage.


Clinical summary Image 7

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