Nodules on the legs. A clinical, histological and immunohistological study of 82 patients representing different types of nodular panniculitis.

Eighty-two cases of nodular panniculitis of the legs were examined clinically, histologically and immunohistologically. Clinically the cases could be divided into four groups: typical erythema nodosum (ENty) (35 cases), erythema nodosum migrans (ENmi) (11 cases), erythema induratum (EI) (11 cases) and the remaining 25 cases not consistent with the others as "non-definite panniculitis" (NDP). The main histological categories were septal panniculitis and lobular panniculitis, the former including erythema nodosum, both typical and migrans, the latter EI and NDP. Lobular panniculitis was divided into three subgroups in which the most prominent histological features were epithelioid cell granuloma, vasculitis and palissading granuloma, respectively. Immunoglobulins in the vessel walls were found in 5 of the 46 cases of erythema nodosum, in 19 of the 36 EI and NDP cases and, in the histological groups in 4 of the 43 cases of septal panniculitis and in 19 of the 35 cases of lobular panniculitis, respectively. Fibrin was found in the walls of the papillary capillaries and deep dermal vessels in the majority of cases of lobular panniculitis. In EI and NDP the follow-up time was 40 months, on average. Twenty-two patients were treated with antituberculous drugs, 15 became symptomless, as did 5 of the 12 patients who were not treated at all.