Granuloma annulare

Evaluating the unusual histological aspects of granuloma annulare: A study of 30 cases

“…[ 1 ] Most of the patients present with asymptomatic, skin-colored to erythematous papular lesions in an annular configuration. Three forms of clinical presentation are most common: generalized GA, localized GA, and subcutaneous GA.[ 2 ] Lesser common clinical variants include perforating GA, palmoplantar GA, blascko-linear GA, pustular, and visceral GA.[ 3 ] Localized form of GA is the most common, with lesions limited to the extremities. Generalized form has been defined as involvement of trunk in addition to one or both the extremities.…”

“…Elastophagocytosis and eosinophilic cell infiltrate have been documented in various studies. [ 3 ] Vascular changes in the form of vessel wall thickening, vasculitis, fibrinoid necrosis, and vascular occlusion have also been reported in rare cases. [ 2 3 ]…”

Case for diagnosis. Patch granuloma annulare

“…Clinical and histological differentiation with reactive granulomatous eruptions can be challenging. 2,5 The term granuloma annulare appropriately describes the classical variant of the disease, with erythematous annular plaques and granulomatous infiltrate when submitted to microscopy. Nevertheless, the disease encompasses a spectrum of clinical presentations, including the localized (most common), disseminated, subcutaneous, papular, perforating, linear and patch forms.…”

“…Nevertheless, the disease encompasses a spectrum of clinical presentations, including the localized (most common), disseminated, subcutaneous, papular, perforating, linear and patch forms. 2,5 The pathogenesis of GA, regardless of its clinical form, includes the presence of chronic vasculitis, the participation of lymphokines with the sequestration of macrophages and histiocytes in the dermis, delayed hypersensitivity reaction, defect in the chemotaxis of neutrophils and infections. 5,6,7 Associations with diabetes, dyslipidemia, malignancies, infections, thyroid diseases and drugs are all reported in the literature, but they require further study in order to be confirmed.…”

“…Triggers, such as contact dermatitis, tattoos, and insect bites, have also been described in the literature. 5,8,9 Histologically, studies suggest that the diffuse interstitial pattern is most common in patch GA, unlike the focal palisading granuloma seen in the majority of other clinical forms. The interstitial pattern is characterized by collections of histiocytes around the collagen bands and blood vessels in the dermis.…”