Answer of Dermatopathology Case 44

Necrobiotic Xanthogranuloma

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Abstracts:

Non-infectious granulomatous diseases of the skin and their associated systemic diseases: an evidence-based update to important clinical questions. Am J Clin Dermatol. 2010;11(3):171-81.
Non-infectious granulomatous diseases of the skin are a broad group of distinct reactive inflammatory conditions that share important similarities. As a group, they are relatively difficult to diagnose and distinguish both clinically as well as histologically. Many of these disorders have significant associations with systemic diseases that impact the patient's overall prognosis. In this update, we offer a discussion of emerging concepts and controversies in this field, as presented through evidence-based answers to seven important clinical questions regarding palisading and epithelioid granulomata. These questions offer an opportunity to review ten non-infectious granulomatous conditions that have implications for systemic disease: granuloma annulare, annular elastolytic giant cell granuloma, necrobiosis lipoidica,methotrexate-induced accelerated rheumatoid nodulosis, necrobiotic xanthogranuloma, interstitial granulomatous dermatitis, interstitial granulomatous drug reaction, palisaded neutrophilic granulomatous dermatitis, sarcoidosis, and metastatic Crohn disease. Recent clinical, epidemiologic, and laboratory studies have shed some light on these diseases, the association of these conditions with systemic disorders, and their overall prognoses.

Necrobiotic xanthogranuloma: a review of 17 cases with emphasis on clinical and pathologic correlation.Arch Dermatol. 2009 Mar;145(3):279-84.
OBJECTIVE: To identify correlations between clinical presentation, specific histopathologic findings, and subsequent disease course in patients with necrobiotic xanthogranuloma (NXG). DESIGN: Retrospective review of medical records and histopathologic examination of fixed tissue samples. SETTING: Tertiary care medical center. PATIENTS: Seventeen patients with a diagnosis of NXG established between January 1, 1994, and December 31, 2007. MAIN OUTCOME MEASURES: Description and distribution of clinical lesions, presence of monoclonal gammopathy, multiple myeloma, and correlation with microscopic patterns of skin lesions. RESULTS: Eleven patients (65%) showed involvement of the periorbital area, and the trunk was affected in 8 patients (47%). Twelve patients (71%) had a monoclonal gammopathy; of these, 3 (18%) had multiple myeloma. Histopathologic examination of 12 patients showed findings consistent with NXG, including a bandlike pattern of necrobiotic granulomatous inflammation, atypical giant cells, cholesterol clefts, and plasma cells. No correlations were identified between clinical presentation and specific histopathologic findings. Although most patients had a serum monoclonal gammopathy, staining with antibodies to CD3, CD20, kappa light chains, and lambda light chains showed polytypic lymphocytes and plasma cells in all cases. CONCLUSIONS: The association between NXG and paraproteinemia is well documented and corroborated by this study. However, the skin lesions in NXG represent reactive inflammation and are not associated with the presence of monoclonal plasma cells or multiple myeloma.

Necrobiotic xanthogranuloma with paraproteinemia; an atypical case.J Dtsch Dermatol Ges. 2008 Jan;6(1):40-3. Epub 2007 Oct 18.
Necrobiotic xanthogranuloma (NXG) is a rare marker for paraproteinemia. An 86-year-old woman had a one year history of large red-yellow to brown annular plaques involving all limbs. Biopsies showed a non-palisading granuloma with numerous multinucleated giant cells showing prominent elastophagocytosis and extensive areas of necrobiosis throughout the entire dermis. Complete loss of elastic fibers was observed in the central atrophic area of an annular plaque. Small vascular thromboses were also present. Laboratory findings revealed paraproteinemia of IgG-lambda type. Immunohistochemical staining detected the presence of roughly equal numbers of IgG-lambda-and IgG-kappa-staining plasma cells in the dermis. We diagnosed NXG with paraproteinemia with monoclonal gammopathy (IgG-lambda type) of unknown significance.