Mechlorethamine has been used for decades to treat cutaneous T cell lymphoma. Rodriguez et al utilized 0.01% topical nitrogen mustard to treat a 60+ year-old man with biopsy-proven NXG with paraproteinemia (IgG-κ), without myeloma. He had 20% body surface area involvement, including the eyelids. He had no response to hydroxychloroquine prior to using mechlorethamine for 24 weeks. He was practically clear at that time, but the treatment was switched to dexamethasone and cyclophosphamide because of ocular involvement of his NXG. (1)
When I first came to Philadelphia in 1984 as a dermatopathology fellow, I remember stepping outside for lunch at a food cart and asking for a pretzel. “With mustard?” the vendor asked. My response was “What? Um…yeah, sure”. I’m not sure how that strange combination started, but I’ve been hooked since. Dr. Rosenbach and his colleagues may be on to something here.
The etiology of NXG is unknown, although a recent study noted that “the lipid profile of patients with NXG was characterized by a low HDL-C phenotype and an abnormal distribution of HDL particles. Sera from patients with NXG induced cholesterol accumulation in human macrophages. This accumulation was due in part to a significant reduction in the HDL capacity to promote cholesterol efflux from macrophages, which was not found in the case of NX” [normolipemic xanthoma]. The authors concluded that the interaction of the paraprotein with lipoproteins may be responsible for the systemic inflammation. (2)
I could not help but wonder if topical nitrogen mustard could be utilized in similar granulomatous disorders to the same beneficial effect. The only reference I could find (cross referencing the drug with granuloma) was for treating a case of an eosinophilic granuloma (Langerhans cell histiocytosis). (3) A rudimentary search for its use in necrobiosis lipoidica, sarcoidosis, or granuloma annulare was non-revealing. It certainly would be worthwhile to try it in severe, recalcitrant patients with any of those disorders.
- Rodrigues O, et al. Necrobiotic xanthogranuloma treated with topical nitrogen mustard (mechlorethamine). JAMA Dermatology 2016; 152: 589-90.
- Szalat R, et al. Physiopathology of necrobiotic xanthogranuloma with monoclonal gammopathy. J Intern Med 2014; 276: 269-84.
- Verret JL, et al. HIstiocytosis X with perianovulvar eosinophilic granuloma. Favorable effect of the local application of nitrogen mustard onto anovulvar lesions. Ann Dermatol Venereol 1985; 112: 165-6.