Kajo Karol, Zubor Pavol, Danko Jan
Department of Pathology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.
Breast Care (Basel). 2010;5(5):331-334. doi: 10.1159/000321341. Epub 2010 Oct 26.
Myoid (muscular) hamartoma (MH) of the breast is a rare benign tumour-forming lesion composed of differentiated mammary glandular and stromal structures, fatty tissue, and areas of smooth muscle. It is considered to be a variant of mammary hamartoma. CASE REPORT: We report the case of a 46-year-old woman with MH, and provide a literature review explaining the origin of smooth muscle cells. Histologically, the tumour consisted of fibrolipomatous stroma containing ductal and lobular structures of the mammary gland located mainly at the tumour borders. The glandular structures showed signs of micro- and macrocystic changes, apocrine metaplasia, and adenosis. The dominant feature was the presence of a fascicular formation of spindle cells, predominantly in central parts, with incursion between glandular structures. Immunohistochemically, foci of smooth muscle tissue were positive for desmin, smooth muscle actin, and h-caldesmon. Oestrogen and progesterone receptors (PR) showed positive expression which was markedly higher for PR. There was negative expression of CD34, S-100 protein, and CD10. CONCLUSIONS: The origin of smooth muscle cells in MH is unknown. However, it is presumed to be derived from hormonally responsive breast stromal cells by smooth muscle metaplasia, based on evidence of hormone receptor expression in the lesion.
乳腺肌样（肌肉）错构瘤（MH）是一种罕见的良性肿瘤形成性病变，由分化的乳腺腺管和间质结构、脂肪组织和平滑肌区域组成。它被认为是乳腺错构瘤的一种变体。病例报告：我们报告了一例46岁患有MH的女性病例，并提供了一篇解释平滑肌细胞起源的文献综述。组织学上，肿瘤由纤维脂肪间质组成，其中包含主要位于肿瘤边界的乳腺导管和小叶结构。腺管结构显示出微囊和大囊改变、大汗腺化生和腺病的迹象。主要特征是存在梭形细胞的束状形成，主要在中央部分，侵入腺管结构之间。免疫组织化学显示，平滑肌组织灶对结蛋白、平滑肌肌动蛋白和h - 钙调蛋白呈阳性。雌激素和孕激素受体（PR）呈阳性表达，PR的表达明显更高。CD34、S - 100蛋白和CD10呈阴性表达。结论：MH中平滑肌细胞的起源尚不清楚。然而，基于病变中激素受体表达的证据，推测其由激素反应性乳腺间质细胞通过平滑肌化生而来。
