Most malignant mesothelioma cases are associated with pulmonary asbestos
body (AB) counts significantly greater than those of the general population.
However, the question remains whether malignant mesothelioma cases associated
with "normal" AB counts (i.e., indistinguishable from the general
population) represent background incidence levels or are, actually, asbestos related.
We performed AB counts (by light microscopy) and mineral fiber analysis
(by scanning electron microscopy) in 18 mesothelioma cases with AB counts
within our normal range (0 to 20 AB/G wet lung) and in 19 "control"
cases. Our study demonstrated that approximately one-third (6 of 18) of
the mesothelioma cases have asbestos fiber burdens greater than 95% of
the control levels. These results suggest that these six mesothelioma
cases may be asbestos related despite AB counts similar to those of the
general population. An asbestos etiology was suggested in three additional
cases, but too few amphibole fibers were identified in these cases to
be certain of a value above background. The remaining nine cases showed
no evidence of an asbestos etiology.
Electron microscopic analysis of pulmonary mineral fibers may be required
to differentiate asbestos-related mesotheliomas from non-asbestos-related
cases when AB counts are within the range of background values.
Malignant mesothelioma associated with low pulmonary tissue asbestos burdens:
a light and scanning electron microscopic analysis of 18 cases. Srebro
SH; Roggli VL; Samsa GP, Mod Pathol, 8(6):614-21 1995 Aug.