Six cases of silicosis were autopsied and the postmortem changes were compared with
clinical manifestations. Gross and microscopic findings of pneumosilicosis were described
and three distinct morbid morphological units, namely, early silicotic nongranulomatous
changes, silicotic granulomatous changes, silicotic granulomatous nodules and
conglomerated silicotic nodular masses, were presented. These three changes proceded in
the order successively in progress and in parallel. However, the last change was
self-limited within the lobar dimension. The details, of each unit were as follows:
Early silicotic non-granulomatous changes.
The earliest chief finding was the accumulation of dust cells laden with silica in the
alveolar spaces and in the alveolar walls. The next stage finding of the earliest change
was composed of many foci with silica laden macrophages and the nearby fibroblasts
proliferation around the small vessels and bronchioles.
Silicotic granulomatous nodules
The nodules consisted of centrally located layers of concentric hyalinized collagenous
tissue lacking macrophages and anthracotic pigments. In the peripheral area of this
nodule. many macrorhages laden with anttracotic pigments and silica and proliferation of
fibrotlasts inter-mingled with anthracotic pigments were found.
Conglomerated silicotic nodular masses
Crossly many nodules, 1∼5mm in size, were conglomerated into a large compact mass
occupying almost the entire lobe. The main changes appeared chiefly in the apex of the
lung and near the hilum. Fibrous tissue between the nodules showed no concentric
arrangement and became partially hyalinized.
Combined changes were as follows: bronchitis, bronchiectasis, tuberculosis, lobar
pneumonia, emphysema and congestion and edema. Among these changes, lobar
pneumonia, marked congestion and edema and corpulmonale seemed to be lethal
complications.
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