Requena Luis, Fernández-Figueras María Teresa
Department of Dermatology, Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spain.
Semin Cutan Med Surg. 2007 Jun;26(2):96-9. doi: 10.1016/j.sder.2007.02.006.
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.
皮下环状肉芽肿是环状肉芽肿一种罕见的临床病理变异型，其特征为皮下结节，可单独出现或与真皮内损害同时存在。这种深部型环状肉芽肿的发病机制仍不明确。皮下环状肉芽肿在儿童和年轻人中更为常见，皮损表现为皮下结节，皮肤表面无炎症表现，最常见于小腿前部、手部、头部和臀部。通常，皮下环状肉芽肿是一种真正的、排他性的脂膜炎性病变，不累及真皮，不过25%的患者皮下环状肉芽肿皮损与真皮内环状肉芽肿的典型表现同时存在。组织病理学上，皮下环状肉芽肿由胶原束嗜碱性变性区域组成，周围栅栏状肉芽肿累及皮下组织间隔。通常，皮下环状肉芽肿的渐进性坏死区域比真皮型的更大。中央渐进性坏死区域在变性胶原束之间含有增多的结缔组织黏蛋白和中性粒细胞核尘。皮下环状肉芽肿中的嗜酸性粒细胞比真皮型更为常见。目前尚无皮下环状肉芽肿呈现所谓不完全或间质型组织病理学模式的描述。皮下环状肉芽肿的组织病理学鉴别诊断包括类风湿结节、类脂质渐进性坏死和上皮样肉瘤。
