Aggressive histiocytic disorders that can involve the skin.

Histiocytoses are a heterogeneous group of disorders that are characterized by the proliferation and accumulation of reactive or neoplastic histiocytes. Three classes of histiocytoses have been defined: class I, Langerhans cell disease; class II, non-Langerhans cell histiocytic disease without features of malignancy; and class III, malignant histiocytic disorders. Although the disorders in classes I and II usually have a benign appearance on histology and are commonly non-aggressive and self-healing, some can cause debilitating or even fatal outcomes. Such cases beg the question: what stimulates aggressive behavior of a classically benign disease? New molecular information may now provide insight into the driving force behind many of the aggressive histiocytoses. In this article, we review Langerhans cell disease and seven aggressive histiocytoses that can involve skin, discuss histologic features that may forecast a poor prognosis, and discuss the molecular findings that help to explain the pathophysiology of these aggressive histiocytic disorders.

Necrobiotic xanthogranuloma.

Necrobiotic xanthogranuloma (NXG) is an uncommon granulomatous disease involving the skin and extracutaneous tissues. In its typical clinical presentation, it consists of multiple indurate yellow-brownish plaques or nodules, usually located on the periorbital area. The lesions often are bilateral and symmetric and frequently show tendency to atrophy and ulceration. Most cases are asymptomatic, and oral mucosal erosions are sometimes present. Ophthalmologic complications are observed in many patients, and NXG may involve other extracutaneous sites. Paraproteinemia is closely associated with NXG, demonstrating a monoclonal gammapathy, and other hematologic or lymphoproliferative disorders also may appear in association with NXG. Large areas of degenerated collagen alternating with granulomatous inflammation, multinucleate giant cells, cholesterol clefts, and lymphoid follicles are the most outstanding histopathologic characteristics of NXG. The prognosis for NXG is good, but no curative treatment is available. Chemotherapy with alkylating agents is the most frequently administered treatment, but oral and intralesional corticosteroids, interferon alpha, plasmapheresis, surgical excision, and radiation therapy also have been used for treatment of this disorder, with variable results.

Granulomatous bronchiolitis with necrobiotic pulmonary nodules in Crohn's disease.

A 37-year-old man with extensive Crohn's disease of the stomach, small and large intestine for almost a decade developed respiratory symptoms and radiological findings suggestive of pneumonia that failed to resolve with antibiotic treatment. Computed tomography scanning of his lungs showed extensive changes with cavitated parenchymal nodules. Histological evaluation of an open lung biopsy showed granulomatous bronchiolitis and pulmonary necrobiosis. Treatment with steroids and immunosuppression resulted in complete resolution of his clinical symptoms of pneumonia and abnormal computed tomography imaging changes. Granulomatous bronchiolitis and necrobiotic nodules may be a manifestation of Crohn's disease in the absence of microbial agents, including mycobacteria or fungal agents. While a multiplicity of complex pulmonary changes may occur in Crohn's disease, their clinical recognition and precise pathological definition may be particularly important if treatment with a biological agent, such as infliximab, is being considered.

Necrobiotic xanthogranuloma: a review of 17 cases with emphasis on clinical and pathologic correlation.

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.

[Long-term course of necrobiotic xanthogranuloma with ocular involvement]. / Langzeitverlauf bei nekrobiotischen Xanthogranulomen mit Augenbeteiligung.

The clinical features of necrobiotic xanthogranuloma (NX) have been presented in a series of case reports, but there are hardly any reports on the clinical long-term course of this rare and usually chronic entity. Therapeutic recommendations are mostly based on individual observations, lacking general therapeutic guidelines. To illustrate a typical chronic and progressive course of NX, we report the case of a 64-year-old woman with periorbital NX, ocular involvement and IgG paraproteinemia. Diagnosed with NX for the first time in 1993, the patient was already presented in this journal in 1995. Since then a series of therapeutic options including medication with dapsone, chlorambucil, interferon-alpha, clofazimine, melphalan, fumaric acid esters, surgical treatment and other physical therapies such as radiation, plasmapheresis, and photodynamic therapy have been applied. None of these therapeutic approaches, however, showed a satisfying long-term effect. At present the patient is undergoing cyclophosphamide-dexamethasone pulse therapy.