实性乳头状癌（SPC）是一种罕见的乳腺乳头状肿瘤变异体。SPC的主要组织学特征包括富含肿瘤细胞的结节，其内部有薄的纤维血管核心，常伴有黏液分泌和神经内分泌分化。浸润性实性乳头状癌（ISPC）肿瘤细胞以侵袭性地展示地图状生长模式，有齿状不规则生长。由于其独特的临床病理特征，基于2019年WHO乳腺肿瘤分类，SPC被分为两种病理性组织类型：原位SPC和浸润性SPC。我们报道了一例55岁女性患者，因左侧乳房无痛性包块持续两年被送入医院。乳房X线照片显示左侧外上象限有一肿块（BI-RADS 4B），乳房超声显示左侧乳房有囊性肿块（US_BI_RADS 4 C），并有多个左腋窝淋巴结肿大。术后病理显示左侧乳房为浸润性实性乳头状癌，1个淋巴结转移。对左侧乳房进行了改良根治性乳房切除术。随后，患者接受了来曲唑内分泌治疗、阿霉素和环磷酰胺化疗，以及左侧胸壁和左锁骨上下区域的放疗。随访17个月后，未见复发和远处转移的证据。SPC是一组异质性肿瘤。原位SPC预后良好。相比之下，浸润性SPC具有独特的组织学形态和侵袭性生长模式，可能导致淋巴结和远处转移。©2023 BioMed Central Ltd., part of Springer Nature.

Solid papillary carcinoma (SPC) is a rare breast papillary tumor variant. The main histological features of SPC consist of neoplastic cell-rich nodules with thin fibrovascular cores, often accompanied by mucous secretion and neuroendocrine differentiation. Infiltrative solid papillary carcinoma (ISPC) tumor cells have an invasive, map-like growth pattern with serrated irregular growth. Due to its unique clinicopathological features, SPC is classified as two pathological tissue types based on the 2019 WHO classification of breast tumors: SPC in situ and ISPC.We report a case of a 55-year-old female patient who was admitted to the hospital due to a painless left breast mass that had persisted for two years. Mammography suggested a mass in the left upper outer quadrant (BI-RADS 4B), and ultrasound of the breast demonstrated a cystic mass of the left breast (US_BI_RADS 4 C) with multiple enlarged lymph nodes in the left axilla. Postoperative pathology revealed ISPC with one lymph node metastasis in the left breast. Modified radical mastectomy was performed on the left breast. Subsequently, the patient received letrozole endocrine therapy, epirubicin hydrochloride and cyclophosphamide chemotherapy, and radiotherapy of the left chest wall and left upper and lower clavicular regions. After 17 months of follow-up, there was no evidence of recurrence or distant metastasis.SPC is a group of heterogeneous tumors. SPC in situ has a good prognosis. In contrast, ISPC has a unique histological morphology and growth pattern with invasive biological behavior that can lead to lymph node and distant metastases.© 2023. BioMed Central Ltd., part of Springer Nature.