Clinicopathological and molecular genetic features of primary renal haemangioblastoma

LEI Cheng-yong; WANG Wei; ZHANG Wei; PENG Da-yun

doi:10.3969/j.issn.1007-8096.2018.06.007

Abstract：Objective To investigate the clinical and pathological characteristics, as well as the molecular genetic changes of primary renal haemangioblastoma. Methods The clinical and pathological data in 2 cases of primary renal haemangioblastoma were collected. The morphological features and immunophenotypes were observed by light microscopy and immunohistochemistry, and PCR sequencing analysis assessed the mutation of VHL gene. Results Case 1 was a 63-year-old male who was found a solid mass on the left kidney during a checkup for backache. Case 2 was a 39-year-old male who presented with a renal mass during a routine examination. Macroscopically, the tumors were well circumscribed and often encapsulated by thick fibrous capsule. The cut surface was grey, whitish yellow or brown. Microscopically, the tumors consisted of sheets and occasionally lobulated nodules of ovoid or polygonal cells with palely eosinophilic and clearly microvacuolated cytoplasm, separated by a prominent arborising vascular network. The blood vessels may be ecstatic. Larger thick-walled veins and rhabdoid cells with abundant eosinophilic cytoplasm could be seen in case 1. No necrosis and mitosis were found. Immunohistochemistry showed positive expression for vimentin, NSE, S-100 and a-inhibin, focally positive for CK and EMA, but negative for CD10, SMA and HMB45. Molecular detection revealed that 3 exons of the VHL gene were not mutated in the 2 cases. Case 1 underwent nephron sparing surgery and case 2 received radical nephrectomy. After 12 and 37 months of follow-up respectively, the two patients showed no evidence of recurrence and metastasis. Conclusion Renal haemangioblastoma is a new added tumor entity in the WHO Classification of Tumours of the Urinary System and Male Genital Organs (2016 edition) which is rare. The diagnosis and diffenertial diagnosis rely mainly on histopathological and immunohistochemical findings. The tumor should be distinguished from renal clear cell carcinoma and epithelioid angiomyolipoma.