INTRODUCTION: Necrobiotic xanthogranuloma is a rare cutaneous disorder usually associated with monoclonal gammapathy. We describe two new cases. EXEGESIS: A 70-year-old patient was affected by a monoclonal gammopathy. She presented with a diplopia related to a retro-orbital tumor. The biopsy showed inflammatory lesions. Five years later, inflammatory xanthomatous skin lesions appeared. Biopsy specimens gave the diagnosis of necrobiotic xanthogranuloma. A 70-year-old woman was referred for inflammatory cutaneous lesions. Clinical, biological investigations and skin biopsies led to the diagnosis of cutaneous sarcoidosis associated with monoclonal gammopathy. Four years later, she developed a nephrotic syndrome. New skin biopsy specimens showed a necrobiotic xanthogranuloma. CONCLUSION: Necrobiotic xanthogranuloma is a systemic disease. It is a rare non-Langerhans cell histiocytosis characterized by frequent cutaneous and ophthalmologic lesions and associated with monoclonal gammopathy. To our knowledge, retro-orbital involvement has never been reported in necrobiotic xanthogranuloma. Treatment is difficult.