摘要
Abstract
Papillary renal neoplasm with reverse polarity(PRNRP)is a rare subtype of renal tumor characterized by distinct histological features.Patients typically present without specific symptoms,and the tumor is often detected incidentally during physical examinations or evaluation for unrelated conditions,which makes misdiagnosis or missed diagnosis common.On April 24,2023,the Inner Mongolia Medical University Affiliated Hospital admitted a rare case of PRNRP.The patient was found to have a right renal mass during a routine physical examination and underwent partial nephrectomy.The tumor measured approximately 4 cm×3 cm×1 cm and appeared cystic-solid on gross examination.Microscopically,the tumor exhibited papillary or tubular structures with fibrovascular cores lined by a single layer of cuboidal to columnar epithelial cells.The tumor cells displayed mild cytologic atypia,uniform size,eosinophilic cytoplasm,and nuclei regularly positioned at the apical side away from the basement membrane.Immunohistochemical staining revealed positive expression of cytokeratin 7,paired box gene 8,epithelial membrane antigen,and endothelial transcription factor 3,with partial expression of vimentin.The tumor cells were negative for CD10,central nervous system specific protein S-100,and transcription factor binding to immunoglobulin heavy chain mu enhancer 3(TFE3),and showed a Ki-67 proliferation index of less than 1％.The patient was followed up for 1 year postoperatively with no evidence of recurrence or metastasis.Due to its rarity,reports on PRNRP remain limited,and more cases are needed to better understand its biological behavior.This case report aims to enhance clinical awareness of PRNRP,helping to avoid misdiagnosis,overtreatment,or missed diagnoses.关键词
乳头状肾肿瘤/极向反转/KRAS/鉴别诊断/免疫组织化学Key words
papillary renal neoplasm/reverse polarity/KRAS/differential diagnosis/immunocytochemistry
