We describe the case of a 25-year-old woman who developed soft tissue ectopic nephritis. Ectopic calcinosis rarely occurs in systemic lupus erythematosus (SLE) patients. This is the first detailed case report of metastatic ectopic calcinosis, one of two categories of ectopic calcinosis, probably due to 1 alpha-OH-vitamin D3 therapy. We administered disodium 3-amino-1-hydroxypropylidene-1, 1-bisphosphonate pentahydrate, a second-generation bisphosphonate, to decrease the patient's serum calcium level, and subsequently observed a dramatic decrease in severity of the ectopic calcinosis along with decreases in both the serum calcium level and the (serum calcium level)x(serum phosphate level) index. We suggest that 1 alpha-OH vitamin D3 should be used in cases of lupus nephritis with great caution.