Miescher's radial granuloma. A characteristic marker of erythema nodosum.

Miescher, in 1947 and 1951, described peculiar radial nodules in erythema nodosum (EN). They consisted of relatively small histiocytes, radially placed around a central cleft. In early lesions, these nodules occurred in association with edema and infiltration of polymorphonuclear leukocytes; later, giant cells originated from the outer borders of the granuloma. Miescher's radial granulomas (MRGs) are mainly located in the interlobular septa and in the deeper layers of the cutis. Although Miescher considered this structure as being specific for EN, it has largely been ignored in the subsequent literature. We have studied 79 biopsy specimens of EN and 182 biopsy specimens of other types of panniculitis. Sixty (76%) of the 79 biopsy specimens of EN disclosed some MRG whereas none was found in the other types of panniculitis. MRG is a characteristic and easily recognizable structure, even at low magnification, and appears to be a useful marker of EN. A detailed study has also been made of the histologic features of EN. Its variations, as well as those of MRG, are related to the chronology of the nodule.