Spleen - Adipocyte Metaplasia
comment:Adipocytes are occasionally seen in the spleen in chronic toxicity/carcinogenicity studies but may be unrelated to treatment. It has been reported in the red pulp of rats exposed to some aromatic amines (e.g., aniline, aniline hydrochloride, para-chloroaniline) and in rats with splenic mesenchymal neoplasms. This lesion is characterized by well-differentiated adipocytes in the red pulp ( Figure 1 and Figure 2 , arrows), surrounded by a fibrous stroma ( Figure 2 , arrowhead), although fibrosis may not always be prominent. The red pulp is typically involved, and the lesion may be focal, nodular, and/or diffuse. These cells most likely arise by metaplasia of splenic stromal cells. Previous terms include "lipidosis," "fatty infiltration," "fatty metamorphosis," and "lipid metaplasia" of the spleen.
recommendation:Whenever present, adipocyte metaplasia of the spleen should be diagnosed and assigned a severity grade. If this lesion is present concurrently or secondarily to neoplasia, it should not be recorded but should be described in the pathology narrative.
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Web page last updated on: January 27, 2015