Journal of Toxicologic Pathology
Online ISSN : 1881-915X
Print ISSN : 0914-9198
ISSN-L : 0914-9198
Case Reports
Accumulation of brown pigment-laden macrophages associated with vascular lesions in the lungs of cynomolgus monkeys (Macaca fascicularis)
Yoshika YamakawaTetsuya IdeHikaru MitoriYuji OishiMasahiro Matsumoto
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2016 Volume 29 Issue 3 Pages 181-184


Accumulation of macrophages containing brown pigments in the lungs is a well-known spontaneous lesion found in cynomolgus monkey. However, its pathogenesis has not been clearly described. In our survey, brown pigment-laden macrophages were found in the lungs of 4 out of 43 cases. Brown pigments were mostly found in the macrophages of the perivascular interstitium, which proved to be hemosiderin. Some small- to medium-sized vessels that exhibited prominent accumulation of brown pigment-laden macrophages showed degeneration and necrosis of the smooth muscle cells of tunica media. Furthermore, ruptures of the internal and external elastic laminae were seen in some of the vessels. These findings suggested that partial fragmentation of the vascular elastic lamina followed by degeneration and necrosis of the tunica media caused blood leakage leading to the accumulation of hemosiderin-laden macrophages in the perivascular interstitium of the lungs.

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© 2016 The Japanese Society of Toxicologic Pathology
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