Subcutaneous Granuloma Annulare

Abstract

Subcutaneous granuloma annulare is a rare clinicopathologic variant of granuloma annulare, characterized by subcutaneous nodules that may appear alone or in association with intradermal lesions. The pathogenesis of this deep variant of granuloma annulare remains uncertain. Subcutaneous granuloma annulare appears more frequently in children and young adults, and the lesions consist of subcutaneous nodules with no inflammatory appearance at the skin surface, most commonly located on the anterior aspects of the lower legs, hands, head, and buttocks. Usually, subcutaneous granuloma annulare is an authentic and exclusive panniculitic process with no dermal participation, although in 25% of the patients lesions of subcutaneous granuloma annulare coexist with the classic findings of granuloma annulare in the dermis. Histopathologically, subcutaneous granuloma annulare consist of areas of basophilic degeneration of collagen bundles with peripheral palisading granulomas involving the connective tissue septa of the subcutis. Usually, the area of necrobiosis in subcutaneous granuloma annulare is larger than in the dermal counterpart. The central necrobiotic areas contain increased amounts of connective tissue mucin and nuclear dust from neutrophils between the degenerated collagen bundles. Eosinophils are more common in subcutaneous granuloma annulare than in the dermal counterpart. There are not descriptions of subcutaneous granuloma annulare showing a histopathologic pattern of the so-called incomplete or interstitial variant. Histopathologic differential diagnosis of subcutaneous granuloma annulare includes rheumatoid nodule, necrobiosis lipoidica and epithelioid sarcoma.

Granuloma Annulare

“…[32][33][34] Lesions appear as firm, asymptomatic, subcutaneous nodules with a tendency to appear on the anterior lower legs, hands, head, and buttocks. 29,33 In 25% of cases, the subcutaneous lesions appear in association with intradermal lesions. These lesions are often biopsied to rule out clinical mimickers, such as rheumatoid nodule, necrobiosis, and epithelioid sarcoma, and sarcoidosis.…”

Annular skin lesions in childhood. Review of the main differential diagnoses

“…In interstitial variant, macrophages are disposed between the collagen bands without forming palisade granulomas. The nodular form is characterized by deep subcutaneous granulomas with necrobiosis, but clinical presentation is not annular, it's nodular [14].…”

Lipoma móvil encapsulado

“…Histológicamente, afecta a la dermis profunda o hipodermis, en forma de focos de degeneración del colágeno y depósito de mucina, rodeados de histiocitos y células gigantes multinucleadas en empalizada. 3 El nódulo reumatoideo es una entidad poco común en niños con artritis idiopática juvenil y ocurre, generalmente, en formas recalcitrantes. La localización más típica son los codos, el dorso de las manos, las rodillas, las orejas y otras zonas de presión.…”

“…Se trata de nódulos color piel, firmes, indurados, no desplazables, cuya histología se diferenciaría del granuloma anular por áreas homogéneas eosinófilas con depósitos de fibrina. 3 Por último, el quiste sinovial es una entidad benigna, localizada fuera de la cápsula articular, pero relacionada anatómicamente con esta por medio de pequeños canales permeables u obliterados. Se origina por degeneración mucinosa, traumatismos o tumores, que desplazarían el líquido sinovial desde regiones de alta a baja presión y provocarían una movilización del tejido sinovial.…”