course controlled by a slow taper of prednisone with onset of symptoms around the time of her CD diagnosis. As in our patient, cPAN is generally responsive to corticosteroids. 3,4 Nonsteroidal anti-inflammatory medications may be useful for prevention and treatment of mild flares and were successfully employed in our patient. We present an instructive case of cPAN pre- senting as a solitary blue toe to make clinicians aware of this unusual presentation in order to facilitate initiation of appropriate work-up and therapy. Amanda Joy Tschetter, MD, a Vincent Liu, MD, a,b and Karolyn A. Wanat, MD a,b Department of Dermatology a and Department of Pathology b at the University of Iowa Hospitals and Clinics, Iowa City Funding sources: None. Conflicts of interest: None declared. Correspondence to: Amanda Joy Tschetter, MD, 200 Hawkins Drive, Iowa City, Iowa 52242 E-mail: Amanda-Tschetter@uiowa.edu REFERENCES 1. Hirschmann JV, Raugi GJ. Blue (or purple) toe syndrome. J Am Acad Dermatol 2009;60:1-22. 2. Begon E, Bouilly P, Cheysson E, Cohen P, Bachmeyer C. Isolated blue toe syndrome as the initial sign of Wegener granulomatosis. Am J Med 2010;123:e7-8. 3. Daoud MS, Hutton KP, Gibson LE. Cutaneous periarteritis nodosa: a clinicopathological study of 79 cases. Br J Dermatol 1997;136:706-13. 4. Komatsuda A, Kinoshita K, Togashi M, Maki N, Masai R, Niitsu H, et al. Cutaneous polyarteritis nodosa in a patient with Crohn’s disease. Mod Rheumatol 2008;18:639-42. 5. Magnant J, Lhommet C, Machet L, Machet MC, Guilmot JL, Diot E. [Cutaneous polyarteritis nodosa and Crohn’s disease: an association not to be ignored]. Rev Med Interne 2009;30: 345-8. http://dx.doi.org/10.1016/j.jaad.2014.03.037 Major response to vemurafenib in patient with severe cutaneous Langerhans cell histiocytosis harboring BRAF V600E mutation To the Editor: We report the case of a female patient in her 90s with a history of age-related macular degeneration and pulmonary embolism. In 2011, she presented with pruritic, erythematous, confluent, maculopapular skin lesions located on the trunk, inframammary fold, groin, and genital and perianal areas. Histology of a skin biopsy revealed a mono- nuclear cell infiltrate that was morphologically and phenotypically consistent with Langerhans cell histiocytosis (LCH) expressing CD1a and S100- protein by immunohistochemistry. A body computed tomography scan showed no visceral involvement, the patient had no exophthalmos or diabetes insipidus, and laboratory tests related to LCH secondary localizations were normal (eg, in- flammatory and hepatic markers, hemogram). Subsequently, a diagnosis of single system cuta- neous LCH was established. Topical and systemic corticosteroid treatments failed to elicit any clinical improvement as first-line treatment, and the patient was suffering from chronic and severe pruritus and pain, affecting her quality of life that declined significantly. A second line of systemic treatment with thalidomide was initiated but was quickly discontinued because the patient experienced minor clinical response with major side effects such as dizziness, asthenia, and impaired coordination. Recently, she experienced a severe new flare of her disease with multiple papulonodular lesions in the same skin areas (Fig 1, before). The patient complained of major pain and had suicidal ideation related to her intolerable skin discomfort. No ex- tracutaneous involvement was found, and a new biopsy confirmed the diagnosis of widespread single system cutaneous LCH (Fig 2, A-C). In conjunction with this finding, the DNA from the biopsy was extracted and a pyrosequencing analysis revealed a BRAF V600E mutation, as expected for up to 57% of LCH cases. 1 After a multidisciplinary consultation, she was started on a third-line vemurafenib treatment, (960 mg orally twice a day) immediately after obtaining written informed consent. Vemurafenib induced a major clinical improve- ment in the first days of treatment. The patient was seen for follow-up 3 weeks after vemurafenib introduction and showed indisputable regression of her cutaneous lesions. Moreover, histopathologic and immunohistochemical studies confirmed the clinical response, in that a new biopsy revealed the absence of remaining cells expressing LCH markers (Fig 2, D and E). After the third month of treatment, the clinical response remained stable and after 6 months of vemurafenib, only scar tissue was notice- able (Fig 1, after). Vemurafenib is an anti-BRAF targeted therapy approved for the treatment of metastatic unresect- able melanoma with V600 mutations; sensitivity to this molecule was recently demonstrated for BRAF mutated non-LCH (ie, CD1- negative Erdheim- Chester disease). 2 Here we report a major clinical response to vemurafenib for refractory, widespread, skin-limited, pure LCH carrying the BRAF V600E JAM ACAD DERMATOL VOLUME 71, NUMBER 3 Letters e97 Open access under CC BY-NC-ND license. CORE Metadata, citation and similar papers at core.ac.uk Provided by Elsevier - Publisher Connector