Atta Ihab S
Pathology Department, Faculty of Medicine, Al-Baha University, Al-Baha, SAU.
Pathology Department, Faculty of Medicine, Al-Azhar University, Cairo, EGY.
Cureus. 2024 Jan 1;16(1):e51427. doi: 10.7759/cureus.51427. eCollection 2024 Jan.
Acinic cell carcinoma (ACC) is an exceedingly rare type of triple-negative breast cancer (TNBC). We are reporting a case of a 46-year-old female patient who presented with a palpable lump in her left breast not associated with pain, pruritis, or change of skin color. An open biopsy revealed a mass of about 20 x 25 mm of fleshy, white tan with a lobular configuration and necrosis. The histopathological examination revealed cells with cytoplasmic granularity arranged in a microglandular pattern and a solid pattern, and the case was initially reported as ACC. The most remarkable feature was the presence of small and large, brightly eosinophilic cytoplasmic granules, and some cells are clear or multivacuolated, resembling lipoblasts. Cellular pleomorphism and anaplasia are very mild, and the mitotic activity was very low. The tumor showed a scant and vascularized stroma in the area of hyalinization. Small clusters of lymphoid infiltration in the stroma were seen. Histochemical stains revealed that the acinar cells in ACC contain abundant diastase-resistant, periodic acid Schiff (PAS)-positive cytoplasmic granules. Mucicarmine and Alcian blue were negative. The immunohistochemistry workup revealed that the case was positive for discovered on gastrointestinal stromal tumors-1 (DOG-1) and the positivity pattern ranged from apical membranous, cytoplasmic, and complete membranous. In addition, the tumor cells were positive for low-molecular-weight cytokeratin, carcinoembryonic antigen (CEA), and epithelial membrane antigen (EMA). The FISH workup for the ETV6-NTRK3 fusion was negative, arguing against secretory carcinoma (SC). A diagnosis of acinar cell carcinoma of the breast is very rare, and the presence of cytoplasmic granules is helpful for its diagnosis. In the absence of these granules, the diagnosis is very difficult, and other diagnoses will be put in the differential diagnosis, particularly SC, lactating adenosis, and microglandular adenosis. Immunohistochemical and histochemical stains and genetic workups will support the diagnosis of ACC.
腺泡细胞癌（ACC）是一种极为罕见的三阴性乳腺癌（TNBC）。我们报告一例46岁女性患者，其左乳出现可触及肿块，无疼痛、瘙痒或皮肤颜色改变。开放性活检显示一个约20×25mm的肉质、灰白色肿物，呈小叶状结构并有坏死。组织病理学检查显示细胞具有细胞质颗粒，呈微腺泡状和实性排列，该病例最初报告为ACC。最显著的特征是存在大小不一、嗜酸性强的细胞质颗粒，一些细胞清晰或多泡状，类似脂肪母细胞。细胞多形性和间变非常轻微，有丝分裂活性很低。肿瘤在玻璃样变区域显示稀少且血管化的间质。间质中可见小簇淋巴细胞浸润。组织化学染色显示ACC中的腺泡细胞含有丰富的抗淀粉酶、过碘酸希夫（PAS）阳性细胞质颗粒。黏液卡红和阿尔辛蓝染色为阴性。免疫组织化学检查显示该病例对在胃肠道间质瘤中发现的-1（DOG-1）呈阳性，阳性模式从顶端膜性、细胞质性到完全膜性不等。此外，肿瘤细胞对低分子量细胞角蛋白、癌胚抗原（CEA）和上皮膜抗原（EMA）呈阳性。针对ETV6-NTRK3融合的荧光原位杂交（FISH）检查为阴性，排除了分泌性癌（SC）。乳腺腺泡细胞癌的诊断非常罕见，细胞质颗粒的存在有助于其诊断。在没有这些颗粒的情况下，诊断非常困难，其他诊断将列入鉴别诊断，特别是SC、哺乳期腺病和微腺泡性腺病。免疫组织化学和组织化学染色以及基因检查将支持ACC的诊断。
