GRANULOMA ANNULARE
Granuloma annulare is listed as a member of the palisading granuloma group of diseases. As such, the pathology is often portrayed with a picture of a  well-developed palisading granuloma. However, in real life most cases of granuloma annulare present with patchy collections of fibrohistiocytic cells in the dermis associated with varying degrees of 'necrobiosis' but without palisading of the fibrohistiocytic cells around the necrobiotic foci.
 
Low power. This picture doesn't really portray the patchy collections of fibrohistiocytic cells as well as can be seen under the microscope. One such collection is in the blue rectangle. Perivascular lymphocytes are also seen.
High power of  the area in the rectangle above. Cells having fibrohistiocytic features are loosely aggregated around the periphery of a focus of altered collagen. Neither palisading nor increased tissue mucin is seen.
Low power of another area in the same biopsy.
High power of the area in the rectangle above.

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