Miettinen Markku, Fetsch John F
Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
Am J Surg Pathol. 2006 Apr;30(4):521-8. doi: 10.1097/00000478-200604000-00014.
Reticulohistiocytoma and multicentric reticulohistiocytosis are designations for uncommon, incompletely characterized histiocytic proliferations of the skin or soft tissues. In this study, we analyzed a uniform group of 44 lesions composed of epithelioid histiocytes, comprising a subset of lesions originally designated as reticulohistiocytoma, and propose designating them as "solitary epithelioid histiocytoma" (SEH), in line with the recently published classification proposal for histiocytic disorders. There were 26 males and 18 females with a median age of 35 years (range, 2.5-74 years). All patients had a superficial, circumscribed, mildly elevated, solitary lesion (size range, 1.5-11 mm; median, 4 mm), located in the trunk wall (n = 16), lower extremity (n = 12), head and neck (n = 8, including 2 in the oral cavity), upper extremity (n = 6), penis (n = 1), and an unspecified site (n = 1). Histologically, the lesions typically involved upper and mid-dermis and were not ulcerated. They were composed of large epithelioid histiocytes with a varying number of lymphocytes and neutrophils. The histiocytes had abundant, typically densely eosinophilic, cytoplasm and mostly mild, if any, nuclear atypia. Multinucleated forms with randomly oriented nuclei were also present. The histiocytes had low mitotic activity (range, 0-4 mitoses per 10 wide HPFs; median, 1 mitosis per 10 HPFs). The lesions contained varying numbers of CD3-positive T cells, whereas B lymphocytes, plasma cells, eosinophils, and mast cells were scant, if present at all. Immunohistochemically, the epithelioid histiocytes were positive for CD163, CD68, lysozyme (variably), and vimentin. They often had focal nuclear immunoreactivity for microphthalmia transcription factor, and they sometimes had focal reactivity for Factor XIIIa and S-100 protein. Membrane positivity for CD31, CD43, and CD45 was variable. The epithelioid histiocytes were consistently negative for CD3, CD20, CD30, HMB45, and keratins. All 12 patients with follow-up information had an uneventful clinical course with no recurrences (median, 13 years). SEH is a benign, probably reactive, histiocytic proliferation of unknown etiology. It needs to be distinguished from Rosai-Dorfman disease, juvenile xanthogranuloma, a variety of granulomatous conditions, and some malignant neoplasms, including histiocytic sarcoma, melanoma, and epithelioid sarcoma.
网状组织细胞瘤和多中心网状组织细胞增生症是皮肤或软组织中罕见的、特征未完全明确的组织细胞增殖的名称。在本研究中，我们分析了一组由上皮样组织细胞组成的44个病变，这些病变最初被指定为网状组织细胞瘤的一个子集，并根据最近发表的组织细胞疾病分类建议，提议将它们命名为“孤立性上皮样组织细胞瘤”（SEH）。患者中男性26例，女性18例，中位年龄35岁（范围2.5 - 74岁）。所有患者均有一个浅表、边界清晰、轻度隆起的孤立性病变（大小范围1.5 - 11毫米；中位值4毫米），位于胸壁（n = 16）、下肢（n = 12）、头颈部（n = 8，包括口腔2例）、上肢（n = 6）、阴茎（n = 1）以及一个未明确的部位（n = 1）。组织学上，病变通常累及真皮上部和中部，无溃疡形成。它们由大量上皮样组织细胞组成，伴有数量不等的淋巴细胞和中性粒细胞。组织细胞具有丰富的、通常为嗜酸性的细胞质，核异型性大多轻微（若有）。也存在核随机排列的多核形式。组织细胞的有丝分裂活性较低（范围为每10个高倍视野0 - 4个有丝分裂；中位值为每10个高倍视野1个有丝分裂）。病变中含有数量不等的CD3阳性T细胞，而B淋巴细胞、浆细胞、嗜酸性粒细胞和肥大细胞（若有）则很少。免疫组织化学检查显示，上皮样组织细胞对CD163、CD68、溶菌酶（变化不定）和波形蛋白呈阳性。它们通常对小眼转录因子有局灶性核免疫反应，有时对因子ⅩⅢa和S - 100蛋白有局灶性反应。CD31、CD43和CD45的膜阳性情况不一。上皮样组织细胞对CD3、CD20、CD30、HMB45和角蛋白始终呈阴性。所有12例有随访信息的患者临床病程平稳，无复发（中位随访时间13年）。SEH是一种病因不明的良性、可能为反应性的组织细胞增殖。它需要与罗萨伊 - 多夫曼病、幼年性黄色肉芽肿、多种肉芽肿性疾病以及一些恶性肿瘤相鉴别，包括组织细胞肉瘤、黑色素瘤和上皮样肉瘤。
