The diagnosis of lupus is suggested by the vacuolar change at the dermoepidermal junction and the inflammatory infiltrate of lymphocytes in the dermis. The lymphoid aggregates in the fat are typical of lupus profundus, but they are also described in deep morphea, erythema nodosum, panniculitis of dermatomyositis and erythema induratum. The substitutive collagenosis in the dermis and fat suggests morphea, and some features of eosinophilic fasciitis are also seen. Consequently, this patient is an example of connective tissue disease with crossover features of lupus erythematosus profundus, morphea profundus, and eosinophilic fasciitis.
Review of slides from the right deltoid revealed focal basilar vaculopathy of the epidermis with a periadnexal infiltrate comprised of lymphocytes and rare plasma cells. In the deep dermis and superficial sucbutaneous tissue there is substitutive collagenosis, and there are lymphoid aggregates in the subcutaneous tissue extending to the fascia. Along the fascia, there is a mixed inflammatory infiltrate with plasma cells. Skeletal muscle is also inflamed.