Maejima Atsushi, Okuno Keisuke, Miyaishi Masanori, Kawaba Daisuke, Kakee Sosuke, Yamaga Kensaku, Namba Noriyuki
Division of Pediatrics and Perinatology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago, Japan.
Division of Orthopedic Surgery, Department of Sensory and Motor Organs, School of Medicine, Tottori University Faculty of Medicine, Yonago, Japan.
J Clin Exp Hematop. 2024 Dec 25;64(4):323-327. doi: 10.3960/jslrt.24056. Epub 2024 Nov 28.
Juvenile xanthogranuloma (JXG) is a rare benign non-Langerhans cell histiocytosis that usually occurs in cutaneous lesions on the head, neck, or upper trunk of neonates and young children. Intramuscular JXG, which invades muscle tissue, accounts for only 0.6% of all JXGs and mostly occurs in the skeletal muscles of the extremities or trunk. A 5-month-old girl was referred to our hospital. At the age of 3 months, she presented with a slow-growing lump on her left thigh. Magnetic resonance imaging (MRI) showed a 22 × 19 × 18 mm oval mass in her left thigh. First, needle biopsy results suggested deep JXG or myeloid sarcoma. Therefore, marginal resection was performed. Intraoperatively, the tumor adhered to the left tensor fasciae latae muscle and was resected together. Histopathological examination revealed a diffuse monotonous sheet-like proliferation of mononuclear histiocyte-like cells with pale, eosinophilic, foamy cytoplasm with a background of muscle and fatty tissue. Minimal mitotic figures and no nuclear atypia or multinucleated giant cells were observed. Immunohistochemical analysis was positive for CD68 (KP-1) and CD163; weakly positive for lysozyme; and negative for CD1a, S100, myeloperoxidase, and CD34. No blast proliferation was observed in the bone marrow. The patient was diagnosed with deep JXG and scheduled for periodic physical examination and MRI. Despite positive margins, the patient fared well without local recurrence 48 months after tumor removal. Understanding the unique pathology of deep JXG and detailed histological evaluation are important for decision-making.
幼年黄色肉芽肿（JXG）是一种罕见的良性非朗格汉斯细胞组织细胞增生症，通常发生于新生儿和幼儿头部、颈部或上躯干的皮肤病变。侵犯肌肉组织的肌内JXG仅占所有JXG的0.6%，主要发生于四肢或躯干的骨骼肌。一名5个月大的女孩被转诊至我院。3个月大时，她左大腿出现一个生长缓慢的肿块。磁共振成像（MRI）显示左大腿有一个22×19×18mm的椭圆形肿块。首先，针吸活检结果提示深部JXG或髓系肉瘤。因此，进行了边缘切除。术中，肿瘤与左阔筋膜张肌粘连，一并切除。组织病理学检查显示单核组织细胞样细胞呈弥漫性、单调的片状增生，细胞质淡染、嗜酸性、泡沫状，背景为肌肉和脂肪组织。观察到极少的有丝分裂象，无核异型性或多核巨细胞。免疫组化分析显示CD68（KP-1）和CD163阳性；溶菌酶弱阳性；CD1a、S100、髓过氧化物酶和CD34阴性。骨髓中未观察到母细胞增殖。该患者被诊断为深部JXG，并计划定期进行体格检查和MRI检查。尽管切缘阳性，但患者在肿瘤切除后48个月情况良好，无局部复发。了解深部JXG的独特病理学和详细的组织学评估对决策很重要。
