Multilocular Cystic Nephroma



Multilocular Cystic Nephroma


Aleksandr Vasilyev, MD, PhD










Gross photograph shows a multilocular cystic nephroma (MCN). The multicystic mass is well circumscribed. The cysts contain clear, thin to gelatinous fluid.






Representative section shows cyst lining epithelium in a MCN. The cyst lining epithelium is flat to low columnar. The stroma of the cyst wall has varied thickness and cellularity.


TERMINOLOGY


Abbreviations



  • Multilocular cystic nephroma (MCN)


Synonyms



  • Cystic nephroma (CN), multilocular cyst


Definitions



  • Benign multicystic neoplasm of renal parenchyma overlapping with mixed epithelial and stromal tumor (MEST) of kidney


ETIOLOGY/PATHOGENESIS


Adult Cystic Nephromas



  • Relationship to sex hormones is suggested



    • Female preponderance


    • Estrogen and progesterone receptor (ER/PR) immunopositivity


    • Associated with sex hormone exposure in both males and females


Pediatric Cystic Nephromas



  • Thought to be etiologically different from adult CN


  • ER/PR are negative


  • Considered to be fully differentiated form of nephroblastoma


CLINICAL ISSUES


Epidemiology



  • Age



    • Adult population, wide age distribution



      • Usually > 30 years


    • Children



      • Usually < 4 years


      • Accounts for ~ 5% of pediatric tumors


  • Gender



    • Female:male ratio is 8:1 in adult cases and 2:1 in pediatric cases


Presentation



  • Most commonly an incidental finding


  • Can present with pain, hematuria


Treatment



  • Conservative surgical excision is curative


  • Very rare cases of local recurrence after surgical excision


Prognosis



  • Excellent prognosis after surgical excision


IMAGE FINDINGS


Ultrasound, CT, or MR Studies



  • While useful, these studies do not allow one to discriminate between MCN and other entities in differential diagnosis in both adult and pediatric cases


MACROSCOPIC FEATURES


General Features



  • Well-circumscribed, encapsulated, multicystic mass


  • Cysts contain clear or gelatinous fluid


  • Often near hilum but may involve cortex in larger lesions


MICROSCOPIC PATHOLOGY


Histologic Features



  • Epithelial lining of cysts ranges from flat to cuboidal to hobnailed to columnar


  • Cytoplasmic clearing of lining epithelium can be seen


  • Fibrous septae show range of cellularity, from paucicellular and hyalinized to highly cellular, reminiscent of ovarian stroma



  • Focal calcifications and atrophic renal tubules can be seen in septae


  • Foamy histiocytes may be present


  • Fibrous pseudocapsule surrounds lesion


ANCILLARY TESTS


Immunohistochemistry



  • ER, PR stains are commonly positive in stroma


  • Inhibin, calretinin, CD10 can also be positive in stroma

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Multilocular Cystic Nephroma
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