Asano Yuka, Kashiwagi Shinichiro, Nagamori Mizuki, Tanaka Sayaka, Kuwae Yuko, Amano Ryosuke, Takashima Tsutomu, Ohsawa Masahiko, Hirakawa Kosei, Ohira Masaichi
Department of Breast and Endocrine Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan.
Case Rep Oncol. 2019 Jul 16;12(2):554-559. doi: 10.1159/000501766. eCollection 2019 May-Aug.
Pure mucinous breast carcinoma with micropapillary pattern (MUMPC) was proposed as a new histopathological variant of pure mucinous carcinoma (PMC) with tumor cells forming a micropapillary architecture. The Classification of Tumours of the Breast by the World Health Organization, however, does not differentiate MUMPC as a distinct subtype. There is currently no consensus whether tumors that exhibit these features are classified as PMC or invasive micropapillary carcinoma (IMPC) with associated mucin production. A 45-year-old woman was examined for a tumor in her left breast. Upon physical examination, an elastic hard mass of around 5 cm along with accompanying skin flare and ulceration was palpated in the upper outer quadrant of the left breast. Mammary ultrasonography revealed a clearly marginated hypoechoic tumor of 55.0 × 46.9 × 37.0 mm in size in the upper outer quadrant of the left breast. A vacuum-assisted biopsy (VAB) was performed in the same site and histopathological diagnosis of PMC was made. Contrast-enhanced magnetic resonance imaging (MRI) showed a T1W1 low-intensity signal and a T2W1 high-intensity signal at the primary focus, ring enhancement of the tumor margin, and stranding enhancement inside the tumor. A preoperative diagnosis of left breast cancer (PMC), cT4bN1M0, stage IIIB, luminal B-like was made. We performed a simple mastectomy with axillary lymph node dissection. A 55.0 × 48.1 × 37.1 mm tumor with the gelatinous cut surface was excised. Histopathological examination of the excised specimen revealed mucin lake formation in the tumor containing clusters of atypical cells. The atypical cells showed swollen, irregular nuclei and a papillary growth pattern that lead to the diagnosis of MUMPC.
具有微乳头结构的纯黏液性乳腺癌（MUMPC）被提出作为纯黏液性癌（PMC）的一种新的组织病理学变异型，其肿瘤细胞形成微乳头结构。然而，世界卫生组织的《乳腺肿瘤分类》并未将MUMPC作为一个独特的亚型区分出来。目前对于表现出这些特征的肿瘤应归类为PMC还是伴有黏液产生的浸润性微乳头癌（IMPC）尚无共识。一名45岁女性因左乳肿物接受检查。体格检查时，在左乳外上象限可触及一个约5 cm的质地硬且有弹性的肿块，伴有皮肤红肿和溃疡。乳腺超声检查显示左乳外上象限有一个边界清晰的低回声肿瘤，大小为55.0×46.9×37.0 mm。在同一部位进行了真空辅助活检（VAB），组织病理学诊断为PMC。对比增强磁共振成像（MRI）显示原发灶在T₁WI呈低信号、T₂WI呈高信号，肿瘤边缘环形强化，肿瘤内部有条索状强化。术前诊断为左乳腺癌（PMC），cT4bN1M0，ⅢB期，Luminal B样。我们进行了单纯乳房切除术加腋窝淋巴结清扫术。切除了一个大小为55.0×48.1×37.1 mm、切面呈胶冻状的肿瘤。对切除标本的组织病理学检查显示肿瘤内有黏液湖形成，其中含有非典型细胞簇。这些非典型细胞显示核肿胀、形态不规则，呈乳头样生长模式，从而诊断为MUMPC。
