Abstract:
Objective: To study the clinicopathological features, immunohistochemical phenotypes, molecular changes, differential diagnosis and prognosis of isolated intraductal carcinoma of the prostate (iIDC-P). Methods: Three iIDC-P cases were collected retrospectively from 2016 to 2022 at Ningbo Clinical Pathology Diagnosis Center, Ningbo, China. The clinicopathologic features and immunophenotypic profiles were studied using light microscopy and immunohistochemistry. A targeted next-generation sequencing panel was used to analyze cancer-associated mutations. Follow-up and literature review were also performed. Results: The patients\' ages were 61, 67 and 77 years, and their preoperative prostate specific antigen (PSA) levels were 7.99, 7.99 and 4.86 μg/L, respectively. Case 1 and 2 were diagnosed on needle biopsy and radical prostatectomy (RP) specimens, and case 3 was diagnosed on a specimen of transurethral resection of the prostate (TURP). The RP specimen was entirely submitted for histologic examination. In the case 1, iIDC-P was found in one tissue core (involving two ducts) in the biopsy specimen, and in 6 sections (diameter, 0.3-1.1 cm) from the radical prostatectomy specimen, and one section had separate foci of low-grade acinar adenocarcinoma (diameter, 0.05 cm). In the case 2, 6 tissue sections from the biopsy specimens showed iIDC-P, and 13 sections from RP specimen showed iIDC-P (diameter, 0.5-1.6 cm), and the other 3 sections had separate low grade acinar adenocarcinoma (diameter, 0.6 cm). In the case 3, 5 tissue blocks from the TURP specimen showed iIDC-P. The case 1 and 2 showed solid architecture with expansile proliferation of neoplastic cells in native ducts and acini. The case 3 showed dense or loose cribriform pattern, with marked cytological atypia, and frequent mitotic figures. Comedonecrosis was found in solid or dense cribriform glands in the case 2. Immunohistochemically, surrounding basal cells were highlighted using high-molecular-weight cytokeratin (34βE12 and CK5/6) and p63, while P504s was positive in the tumor cells. The tumor cells were also positive for AR and prostate markers (NKX3.1, PSA and PSAP), and negative for GATA3. The iIDC-P and acinar adenocarcinoma both showed weak PTEN expression and no ERG (nuclear) expression. In case 2 and 3, targeted sequencing revealed activated oncogenic driver mutations in MAPK and PI3K pathway genes (KRAS, MTOR and PTEN). In addition, pathogenic mutation in TP53 and FOXA1 mutation were found in the case 2 and 3, respectively. No case demonstrated TMPRSS2::ERG translocation. All cases were microsatellite stable and had lower tumor mutation burdens (range, 2.1-3.1 muts/Mb). The patients showed no biochemical recurrence or metastasis after follow-up of 16-91 months. Conclusions: iIDC-P is a special type of intraductal carcinoma of the prostate and differs from intraductal carcinoma within high-grade prostate cancer. iIDC-P has unique molecular characteristics and may represent as a molecularly unique in situ tumor of prostate cancer.
目的: 探讨前列腺孤立性导管内癌(isolated intraductal carcinoma of the prostate,iIDC-P)的临床病理特征、分子改变、鉴别诊断及预后。 方法: 回顾性收集宁波市临床病理诊断中心2016—2022年间的3例iIDC-P的临床病理学资料,进行光镜观察、免疫组织化学染色、高通量DNA靶向测序及随访,并复习相关文献。 结果: 例1~3患者年龄分别为61、67、77岁,术前总前列腺特异性抗原(TPSA)水平分别为7.99、7.99、4.86 μg/L。例1和例2包含前列腺穿刺和根治标本,例3为经尿道前列腺电切标本。镜下:例1穿刺标本仅1条组织见导管内癌(累及2个导管)、根治标本其中6张切片见导管内癌(病灶直径0.3~1.1 cm),其中1张切片见小灶低级别腺泡腺癌(病灶直径0.05 cm)。例2穿刺标本6条组织见导管内癌,根治标本其中13张切片见导管内癌(病灶直径0.5~1.6 cm),另外3张切片可见低级别腺泡腺癌(最大病灶直径0.6 cm)。例3电切标本其中5条组织见导管内癌。例1和例2导管内癌呈实性生长,导管-腺泡显著膨胀,核显著异型;例3呈致密筛状或疏松筛状结构,核显著异型,核仁明显。例2伴有粉刺样坏死,3例核分裂象均易见。导管内癌免疫表型:双标34βE12+P504s显示基底细胞表达34βE12/异型肿瘤细胞表达P540s,p63和CK5/6显示腺泡/导管周围基底细胞,肿瘤细胞表达NKX3.1、雄激素受体、前列腺特异性抗原、前列腺特异性酸性磷酸酶,不表达GATA3,导管内癌和腺泡腺癌均弱表达PTEN、不表达ERG。高通量DNA靶向测序:例2和例3伴有MAPK/PI3K通路基因改变(KRAS、MTOR和PTEN),例2伴有p53突变、例3伴有FOXA1突变。3例均未发现TMPRSS2::ERG融合,3例均显示微卫星稳定,肿瘤突变负荷低(2.1~3.1 muts/Mb)。随访16~91个月,均无生化复发及远处转移。 结论: iIDC-P是一种特殊的前列腺导管内癌,不同于伴有高级别前列腺癌的前列腺导管内癌,具有独特的分子改变,可能代表一种特殊类型前列腺癌的原位病变。.