Vulvar necrobiotic xanthogranuloma
Authors: Ilana J. DeLuca, Marc E. Grossman
Journal: Journal of the American Academy of Dermatology (2014)

To the Editor: An 89-year-old Caucasian woman with a 1.5-year history of IgG monoclonal gammopathy of undetermined significance presented for evaluation of a large ulceration on the left buttock and an asymptomatic lesion on the vulva. On physical examination, she had an extensive well-defined indurated ulcer obliterating the clitoris and encompassing both labia majora (Fig 1, A) and an 8- × 8-cm circular ulcer extending down to muscle on the left buttock with a necrotic rim (Fig 1, B). A 1.5-cm yellow nodule was present on the left lower eyelid, and a 4-cm oval yellow-pink plaque on the lateral distal aspect of her right thigh (Fig 1, C). The patient was given the diagnosis of monoclonal gammopathy of undetermined significance 1.5 years before presentation with serum protein electrophoresis demonstrating 0.58 g/dL of monoclonal IgG paraprotein and elevated free kappa and lambda light chains. She refused bone-marrow biopsy. Laboratory studies were significant for stable anemia (hemoglobin of 10 g/dL), normal white blood cell count, normal complete metabolic panel findings, and normal liver function test results. Wedge biopsy specimen of the vulvar lesion and excisional biopsy specimen of the right leg plaque both showed large areas of necrosis surrounded by a prominent granulomatous reaction with histiocytes and multinucleated giant cells, consistent with necrobiotic xanthogranuloma (NXG) (Fig 2). The lesional cells stained positive for CD68 and CD163, in keeping with histiocytes. Pancytokeratin, S100 protein, and CD34 were negative. Special stains for organisms (Gomori methenamine silver and acid-fast bacillus) produced negative findings. NXG with paraproteinemia is a rare, chronic granulomatous disorder that presents as indurated yellow papules, plaques, and nodules in association with a serum monoclonal gammopathy. Skin biopsy specimen demonstrates a dermal infiltrate composed of palisading granulomas with areas of necrosis and prominent giant cells. Most patients (80%) with NXG have a serum monoclonal gammopathy and a small percentage (10%) develop multiple myeloma.1Wood A.J. Wagner V.U. Abbott J.J. Gibson L.E. Necrobiotic xanthogranuloma.Arch Dermatol. 2009; 145: 279-284Crossref PubMed Scopus (106) Google Scholar The vast majority of patients have periorbital lesions, particularly on the upper or lower eyelid, as in this case.2Spicknall K.E. Mehregan D.A. Necrobiotic xanthogranuloma.Int J Dermatol. 2009; 48: 1-10Crossref PubMed Scopus (75) Google Scholar Other sites of involvement include the face, trunk, and extremities.3Mehregan D.A. Winkelmann R.K. Necrobiotic xanthogranuloma.Arch Dermatol. 1992; 128: 94-100Crossref PubMed Scopus (177) Google Scholar, 4Efebera Y. Blanchard E. Allam C. Han A. Lee A. Munshi N. Complete response to thalidomide and dexamethasone in a patient with necrobiotic xanthogranuloma associated with monoclonal gammopathy: a case report and review of the literature.Clin Lymphoma Myeloma Leuk. 2011; 11: 298-302Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar There are only 2 cases of NXG with mucosal or genital involvement reported in the literature. Fortson and Schroeter5Fortson J.S. Schroeter A.L. Necrobiotic xanthogranuloma with IgA paraproteinemia and extracutaneous involvement.Am J Dermatopathol. 1990; 12: 579-584Crossref PubMed Scopus (49) Google Scholar reported a case of NXG of the lips and tongue, and a review by Wood et al1Wood A.J. Wagner V.U. Abbott J.J. Gibson L.E. Necrobiotic xanthogranuloma.Arch Dermatol. 2009; 145: 279-284Crossref PubMed Scopus (106) Google Scholar cited a 26-year-old man with penile NXG in a table summarizing the clinical findings in 12 patients with NXG. To our knowledge, this is the first case of NXG involving the female genitalia. Given the dramatic presentation and extent of genital involvement in this elderly female patient, the leading gynecologic diagnosis was squamous cell carcinoma. Biopsy specimen of the vulvar lesion was essential to rule out underlying malignancy and establish the diagnosis. The patient refused further workup and died 2 weeks after presentation from failure to thrive, although multiple myeloma cannot be ruled out as her underlying cause of death. This case demonstrates the potential for NXG to rapidly progress, leading to dramatic ulceration with significant morbidity and mortality and underscores the need for early recognition of this rare condition. Treatment options for NXG include surgery, intralesional and systemic corticosteroids, and other systemic therapies such as methotrexate, cyclophosphamide, and azathioprine. Vulvar NXG is now an entity that both dermatologists and gynecologists should be aware of, requiring prompt evaluation with biopsy and treatment to prevent potentially disfiguring and debilitating obliteration of the external female genitalia.