S12C22aP12a Miescher's granuloma



S12c22aP12a-1: This lady had lesions of the face, ear, and scalp. At low magnification, the lesion is expansile and rounded in outline. It is mostly confined to the reticular dermis; the epidermis and papillary dermis are spared. There are perivascular and peri-appendageal infiltrates of lymphoid cells at the periphery of, and within, the lesion. Centrally, collagen bundles are swollen; they are closely spaced and more acidophilic than those of the adjacent, uninvolved dermis. Histiocytes form palisades at the periphery of the zone of altered dermal connective tissue. They form traceries among the altered collagen bundles ( Miescher’s granuloma).

S12C22aP12a-2: The patterns are those of a palisaded granuloma. In scattered areas, features are smudgy within the zone of altered connective tissue; these smudgy, basophilic zones represent small areas of necrosis. The expansile qualities are evident.


S12C22aP12a-3: The epidermis is hyperplastic; the basal unit is hyperplastic and the keratinocytes of the basal unit have pale cytoplasm. The acrosyringium, to the right in the epidermis, serves as a built-in control by which the pallor of the cells of the basal unit of the epidermis can be evaluated. The papillary dermis is thin and fibrotic. At the interface between the papillary dermis and the reticular dermis, the infiltrates of lymphoid cells are band-like. In the reticular dermis, histiocytes form traceries among altered collagen bundles. There are scattered multinucleated giant cells.

S12C22aP12a-4; The patterns of a palisaded granuloma are represented. To the right, the patterns are of the so-called interstitial type with traceries of histiocytes among collagen bundles of the reticular dermis. To the left, there is a zone of necrosis. Bordering the area of necrosis, collagen bundles are swollen. At the periphery of the area of necrosis, near the top of the field, histiocytes form prominent palisades.

S12C22aP12a-5: Interstitial infiltrates of histiocytes form traceries among clusters of collagen bundles of the reticular dermis. Giant cells are a prominent feature. Xanthomatous changes are not a feature.

S12C22aP12a-6: Histiocytes form prominent palisades about a zone of altered connective tissue (partially represented at the bottom of the field). A red arrow points to an elastic fiber entrapped in the infiltrate of histiocytes. There is a mitotic figure in the infiltrates, to the right of the center of the field.

The nature of Miescher’s granuloma is uncertain. A review of Miescher’s photographs would offer support for the interpretation that the process, which he described, is an actinic granuloma. The nature of the process has been clouded by the opinion of other observers that Miescher’s granuloma is a variant of necrobiosis lipoidica diabeticorum (i.e., atypical necrobiosis lipoidica). A plasmacytic component in the adjacent lymphoid infiltrates might be offered in support of such an interpretation. Finally, the pattern, in this example, shares many features with those of lesions of granulomatous interstitial dermatitis of immune complex disease.

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