5例嗜酸性实性和囊性肾细胞癌的临床病理特征OA

Objective:Eosinophilic solid and cystic renal cell carcinoma(ESC RCC)is a rare tumor entity newly included in the 5th edition of the World Health Organization classification of renal tumors.Histologically,it is characterized by a mixed solid and cystic architecture with abundant eosinophilic cytoplasm.Given its rarity and limited current understanding,this study aims to investigate the clinical presentation,histopathological features,immunohistochemical characteristics,and differential diagnostic points of ESC RCC,thereby providing a reliable reference for accurate diagnosis,individualized treatment,and prognostic evaluation. Methods:Five patients with ESC RCC who underwent surgical resection and were pathologically confirmed in the Department of Urology at the First Affiliated Hospital of Anhui Medical University from June 2022 to May 2025 were retrospectively included.Complete clinicopathological data and postoperative follow-up information were collected.The clinicopathological features were analyzed based on histological architecture,cytological morphology,and immunohistochemical findings,and relevant domestic and international literature was systematically reviewed. Results:All 5 patients were female,with a median age of 61 years.Four patients presented with mild,intermittent dull flank pain without radiation or accompanying symptoms.One case was incidentally detected during routine physical examination by abdominal imaging and was asymptomatic.Imaging studies revealed that all tumors were unilateral and solitary,located in the cortical region of the left kidney,with clear boundaries from the renal medulla and no invasion of the renal pelvis or perirenal fat.The maximum tumor diameter ranged from 4.8 to 6.7 cm,with a mean maximum diameter of 5.8 cm.On non-contrast imaging,lesions showed heterogeneous or slightly hyperdense signals;contrast-enhanced scans demonstrated mild to moderate heterogeneous enhancement.Grossly,tumors appeared gray-yellow or brownish,well circumscribed,without an obvious capsule.Microscopically,tumors predominantly exhibited solid growth with focal microcystic structures of varying sizes.Tumor cells were polygonal or round,arranged in nests or sheets,with well-defined cell borders and abundant intensely eosinophilic cytoplasm.Fine granular basophilic stippling was observed in some cytoplasm,representing a characteristic morphological feature of this tumor.Nuclei were round or oval with inconspicuous nucleoli,and mitotic figures were rare[≤1/10 high-power fields(HPF)].One case showed vascular tumor thrombus.Immunohistochemically,tumor cells in all 5 cases showed varying degrees of positivity for cytokeratin(CK)20(cytoplasmic),paired box gene 8(PAX8)(nuclear),alpha-methylacyl-CoA racemase(AMACR)(cytoplasmic),succinate dehydrogenase subunit B(SDHB)(cytoplasmic),and vimentin(cytoplasmic),while CK7 and human melanoma black 45(HMB45)were negative.One case showed focal positivity for CD117(membranous)and carbonic anhydrase IX(CA-IX)(membranous).Of the 5 patients,2 underwent radical nephrectomy and 3 underwent partial nephrectomy.No serious postoperative complications such as bleeding,infection,or urinary fistula occurred,and all patients were discharged uneventfully.Follow-up was conducted until December 2025,with a duration ranging from 6 to 42 months.One patient was lost to follow-up,while the remaining 4 patients survived without evidence of recurrence or metastasis. Conclusion:ESC RCC predominantly occurs in middle-aged women and is characterized by a distinctive"solid and microcystic"histological pattern and a"CK20+/CK7-"immunophenotype.Immunohistochemistry is useful for distinguishing it from other eosinophilic renal tumors.Surgical resection is associated with a favorable prognosis.