Tubulocystic Carcinoma



Tubulocystic Carcinoma


Satish K. Tickoo, MD

Danielle E. Westfall, MD

Victor E. Reuter, MD





Key Facts


Terminology



  • Tubulocystic carcinoma (TC) of kidney



    • Well-circumscribed carcinoma with pure tubular and cystic architectural growth


    • Cysts and tubules lined by single layer of atypical cells with abundant eosinophilic cytoplasm and variable “hobnailed” appearance


Clinical Issues



  • Uncommon; < 60 cases reported in literature


  • Considered potentially of low malignant behavior


  • Strong male preponderance; M:F = 7:1 or greater


Macroscopic Features



  • Well-circumscribed tumors with spongy “bubble wrap” appearance


Microscopic Pathology



  • Composed of small to intermediate-sized tubules admixed with cystically dilated tubules, dispersed evenly in frequently fibrotic stroma


  • Tubule and cyst lining composed of single layer of flat, “hobnail,” or cuboidal to columnar cells


  • Cellular stratification and papillations very focal and uncommon


Ancillary Tests



  • Majority are positive for CK7, CK19, parvalbumin, CD10, AMACR, and Ksp-cadherin


Top Differential Diagnoses



  • Collecting duct carcinoma with TC-like areas


  • Other adult renal epithelial tumors with predominant tubules and cysts







Gross photograph demonstrates a well-circumscribed tumor with a spongy cut surface and variable sized cysts, the typical gross appearance of a tubulocystic carcinoma.






A low-power view of tubulocystic carcinoma shows variably sized tubules and cysts, lined by a single layer of epithelium.


TERMINOLOGY


Abbreviations



  • Tubulocystic carcinoma (TC) of kidney


Definitions



  • Well-circumscribed renal cell carcinoma (RCC) with pure tubular and cystic architectural growth



    • Cysts and tubules lined by single layer of atypical cells with abundant eosinophilic cytoplasm and variable “hobnail” appearance


ETIOLOGY/PATHOGENESIS


Historic Perspective



  • Initially described in 1956 by Masson and designated as Bellinien epithelioma


  • Examples illustrated in 3rd AFIP fascicle as collecting duct carcinoma (CDC), subsequently designated low-grade CDC



    • This group also contained some cases now regarded as mucinous tubular and spindle cell carcinoma


  • Recently considered as distinct entity



    • Exact relationship with collecting duct carcinoma still unclear



      • Particularly because areas with TC-like morphology are occasionally observed in otherwise typical CDCs


Molecular Abnormalities



  • Unique molecular signature distinct from clear cell and chromophobe RCC reported in Affymetrix X3P oligonucleotide microanalysis



    • Overexpression of genes related to



      • Amino acid metabolism


      • Cell cycle


    • Underexpression of many biopolymer metabolism genes


  • Based on a single case, using clustering analysis, molecular signature also reported to be closely related to papillary RCC


  • No published large molecular study analyzing relationship to, or distinction from, collecting duct carcinoma


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Uncommon; < 60 cases reported in literature


  • Age



    • 34-94 years (mean: 60 years)


  • Gender



    • Strong male preponderance; M:F = 7:1 or greater


Presentation



  • Majority asymptomatic, incidentally discovered radiologically; occasionally abdominal fullness, flank pain, or hematuria


Treatment



  • Usually amenable to surgical treatment due to low tumor stage at presentation


  • Single reported case of metastatic disease treated with multikinase inhibitor sunitinib as adjuvant with documented clinical and radiographic regression


Prognosis

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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Tubulocystic Carcinoma

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