Supplementary Material for: Apocrine adenoma of the breast showing unique image findings

Introduction: Apocrine adenoma of the breast is extremely rare and its typical images remain uncertain. Case presentation: A 66-year-old woman was incidentally found of her left breast tumor with computed tomography for ascending colon cancer staging work. Mammography showed a well-demarcated oval mass. Ultrasonography showed an oval mass with indistinct borders, internal iso-echoes with multiple high echo spots, and unchanged posterior echoes. Magnetic resonance imaging of the mass showed a hypo intense pattern both on T1- and T2-weighted images and a long-lasting rim enhancement pattern up to the late phase on time-signal intensity images. Probably due to the inappropriate tissue sampling, no definitive pathological diagnosis was obtained with core needle biopsy, forcing us to do lumpectomy of the breast mass at the time of colon cancer surgery. The resected breast mass was hard, clearly-demarcated, and 8mm in size. Cut surface of the mass was flesh-colored and had multiple white spots. Pathological study showed dense predominantly oval glandular ducts with luminal apocrine cell layers, outer myoepithelium cell layers, and slight fibrosis. Glandular cavities on pathology well matched to the white spots on macroscopic view, seemed vacant in a cyst-like fashion, and had aggregated foamy histiocytes in some of them. These pathological findings led us to the diagnosis of apocrine adenoma of the breast. Conclusion: Diagnostic physicians should note this extremely rare breast disorder and its image findings.

引言：乳腺顶泌腺腺瘤（Apocrine adenoma of the breast）极为罕见，其典型影像学表现迄今尚未明确。病例报告：一名66岁女性因升结肠癌分期评估接受计算机断层扫描（Computed Tomography, CT）时，意外发现左侧乳腺肿物。乳腺钼靶检查可见边界清晰的椭圆形肿物。超声检查显示该肿物为椭圆形，边界不清，内部呈等回声并伴多个高回声点，后方回声无明显变化。该乳腺肿物的磁共振成像（Magnetic Resonance Imaging, MRI）在T1加权及T2加权序列均呈低信号，时间-信号强度曲线显示延迟相仍可见持续存在的边缘强化模式。由于组织采样可能不恰当，核心针穿刺活检未能获得明确病理诊断，因此我们在结肠癌手术同期实施了乳腺肿物切除术。切除的乳腺肿物质地坚硬、边界清晰，大小为8mm。肿物切面呈肉色，伴多个白色斑点。病理检查可见以椭圆形腺管为主的致密结构，腺管内衬顶泌腺细胞层、外层肌上皮细胞层，并伴轻度纤维化。病理所见的腺腔与大体标本上的白色斑点高度吻合，部分腺腔呈囊性中空状态，其内可见聚集的泡沫状组织细胞。上述病理表现最终确诊为乳腺顶泌腺腺瘤。结论：临床与影像诊断医师需警惕这一极为罕见的乳腺病变及其影像学特征。