Tanahashi Jin, Kashima Kenji, Daa Tsutomu, Kondo Yoshiyuki, Kuratomi Eiji, Yokoyama Shigeo
Department of Pathology, Faculty of Medicine, Oita University, Yufu City, Japan.
J Cutan Pathol. 2007 Aug;34(8):648-53. doi: 10.1111/j.1600-0560.2006.00676.x.
Cutaneous myoepithelioma, both benign and malignant, is a rare neoplasm composed of neoplastic myoepithelial cells showing diverse histopathological features, and criteria for discriminating benign or malignant have not been fully clarified.
We present a case of cutaneous myoepithelial carcinoma in a 62-year-old woman presenting a solid mass in the right back.
Resected tumor was located in the whole dermis and subcutis. Histopathologically, two different growth patterns were noted: a small-nested or trabecular pattern in the superficial part and a large nodular pattern with extensive central necrosis in the deep part. Tumor cells were all epithelioid, although plasmacytoid and glycogen-rich clear cells were also observed within the large nodules of the deep part. Immunohistochemically, the cells were positive for both epithelial and myogenic markers, suggesting myoepithelial origin. Lymphatic invasion and lymph node metastasis were evident despite inconspicuous atypia and low mitotic rate.
The final diagnosis was cutaneous myoepithelial carcinoma. At present, it seems to be difficult to predict the behavior of myoepithelioma of the skin and soft tissue, although atypia and high mitotic rate are reported to be associated with local recurrence and metastasis.
皮肤肌上皮瘤，包括良性和恶性，是一种罕见的肿瘤，由具有多种组织病理学特征的肿瘤性肌上皮细胞组成，区分良性或恶性的标准尚未完全明确。
我们报告一例62岁女性的皮肤肌上皮癌，其右背部出现一个实性肿块。
切除的肿瘤位于整个真皮和皮下组织。组织病理学上，观察到两种不同的生长模式：浅表部分为小巢状或小梁状模式，深部为大结节状模式且伴有广泛的中央坏死。肿瘤细胞均为上皮样，尽管在深部的大结节内也观察到浆细胞样和富含糖原的透明细胞。免疫组化显示，细胞上皮和肌源性标志物均呈阳性，提示肌上皮起源。尽管异型性不明显且有丝分裂率低，但仍有明显的淋巴侵袭和淋巴结转移。
最终诊断为皮肤肌上皮癌。目前，尽管据报道异型性和高有丝分裂率与局部复发和转移有关，但似乎很难预测皮肤和软组织肌上皮瘤的行为。
