Kidney tumor - adult malignancies
Adult renal cell carcinoma
Hybrid oncocytic / chromophobe tumor

Author: Julie Guilmette, M.D. (see Authors page)
Editors: Roula Albadine, M.D.

Revised: 2 February 2017, last major update September 2015

Copyright: (c) 2002-2017, Inc.

PubMed Search: Hybrid oncocytic chromophobe tumor
Cite this page: Hybrid oncocytic / chromophobe tumor. website. Accessed March 24th, 2018.
Definition / general
  • Hybrid oncocytic / chromophobe tumor (HOCT) is a rare renal neoplasm classified as a subcategory of chromophobe renal cell carcinoma (Am J Surg Pathol 2013;37:1469)
  • Displays histological features of both renal oncocytoma (RO) and chromophobe renal cell carcinoma (ChRCC) including areas composed of "hybrid" cells with overlapping cytonuclear or histochemical features (Virchows Arch 2013;462:633)
  • Occurs (or arises) in three clinical settings: a sporadic tumor, associated with renal oncocytomatosis, and as a component of Birt-Hogg-Dubé syndrome (Histol Histopathol 2013;28:1257)
  • Epidemiology
  • Typically occurs in adult males with an age range of 41 - 68 years (mean of 56) (BJU Int 2009;103:1381)
  • Sites
  • Kidney: can develop either unilaterally (sporadic) or bilaterally (Histol Histopathol 2012;27:1407)
  • Clinical features
  • No specific clinical symptoms reported in patients with sporadic or associated with renal oncocytosis (Histol Histopathol 2013;28:1257)
  • Patients with Birt-Hogg-Dubé syndrome usually have characteristic clinical features: skin tumors such as fibrofolliculoma or trichodiscoma, pulmonary lesions including bullae and spontaneous pneumothorax (Histol Histopathol 2012;27:1407)
  • Radiology images
  • Unilateral or bilateral solid enhancing lesions (Radiology 2003;226:33)
  • May be multifocal
  • Classically, lesions enhance after contrast administration and can be distinguished from cysts (Radiology 2003;226:33)
  • Renal cysts may be seen (Pol J Pathol 2014;65:93)
  • Prognostic factors
  • Good prognosis as no aggressive behavior has yet been described (Virchows Arch 2010;456:355)
  • Currently, no report with follow up longer than 10 years has been published; therefore, a low malignant potential may not be eliminated (Histol Histopathol 2013;28:1257)
  • Case reports
  • 12 year old girl with hybrid renal cell carcinoma (Pediatr Hematol Oncol 2010;27:228)
  • 48 year old woman with multiple renal hybrid oncocytic tumors and Birt-Hogg-Dubé syndrome (Acta Cytol 2006;50:584)
  • 52 year old woman with nonalcoholic steatohepatitis and right kidney mass (Case of the Week #379)
  • Renal oncocytoma containing "chromophobe" cells (Int J Urol 1995;2:279)
  • Treatment
  • Radical nephrectomy or nephron sparing surgery (Am J Surg Pathol 2013;37:1469, Eur Urol 2010;57:661)
  • Some patients may be candidates for active surveillance, and surgery may be unnecessary (Eur Urol 2010;57:661)
  • Gross description
  • Variable size, from 2 to 11 cm (Virchows Arch 2010;456:355)
  • Well demarcated, unencapsulated mass
  • Homogeneous tan to brown in color (J Urol 2011;186:2413)
  • Central scar may be seen (Histol Histopathol 2013;28:1257)
  • Necrosis is uncommon (Pol J Pathol 2014;65:93)
  • Microscopic (histologic) description
  • Non infiltrative, well circumscribed intrarenal tumor
  • Solid alveolar and cystic architecture
  • Dual population of eosinophilic cells: oncocytic and chromophobe
  • Oncocytic cell: medium sized round cell with granular eosinophilic cytoplasm and concentric round nucleus with prominent nucleolus (Virchows Arch 2010;456:355)
  • Chromophobe cell: large, polygonal "plant-like" cell with a distinct cell membrane, containing flaky eosinophilic cytoplasm often with a perinuclear halo and an irregular "raisinoid" wrinkled nucleus
  • Third cell type may be seen with cytonuclear features overlapping both oncocytic and chromophobe morphology (Virchows Arch 2013;462:633)
  • May have vascular invasion (Pathol Res Pract 2005;201:385)
  • Mitotic rate is very low
  • Rarely have necrosis (Pol J Pathol 2014;65:93)
  • Microscopic (histologic) images

    Images hosted on PathOut server:

    Case of the Week #379:






    Hale colloidal iron

    Images hosted on other servers:

    Images courtesy of Chin-Lee Wu, Ph.D., Harvard School of Medicine:

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    Dual population of eosinophilic cells

    Images courtesy of Roula Albadine, M.D. and Julie Guilmette, M.D.:

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    Flaky eosinophilic cytoplasm

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    Oncocytic cells with granular eosinophilic cytoplasm, concentric round nucleus and prominent nucleoli

    Missing Image

    Hale colloidal iron

    Cytology description
  • Sheets of oncocytic cells with low nuclear:cytoplasmic ratios and uniform round nuclei (Acta Cytol 2006;50:584)
  • Rare cells with clear cytoplasm and slightly larger, irregular nuclei (Acta Cytol 2006;50:584)
  • Positive stains
  • Cytokeratins: CK7 (may be focal), CK AE1 / AE3
  • Parvalbumin, antimitochondrial antigen, EMA, E-cadherin (most), CD117 (Histol Histopathol 2013;28:1257, Virchows Arch 2010;456:355)
  • S100A1, CD82 (Pathol Int 2015;65:126)
  • Vimentin (few cases) (Pathol Res Pract 2005;201:385)
  • Hale colloidal iron stains apical / luminal oncocytic cells and often intracytoplasmic in chromophobic cells (Pathol Res Pract 2005;201:385)
  • Molecular / cytogenetics description
    • May be associated with BHD, autosomal dominant syndrome characterized by a genetic abnormality on chromosome 17p11.2 leading to a mutation in the FLCN gene (Pol J Pathol 2014;65:93)
    • Sporadic forms may present with numerous molecular anomalies (both mono- and polysomies) of chromosomes 1, 2, 6, 9, 10, 13, 17, 21, and 22 and lack of mutations in the VHL, c-kit, PDGFRA, and FLCN genes (Virchows Arch 2010;456:355)
    Electron microscopy description
  • Numerous mitochondria
  • Sparse microvesicles with amorphic lamellar content
  • Infrequently, small intracytoplasmatic tubuli covered by microvilli may be observed (Virchows Arch 2010;456:355)
  • Differential diagnosis
  • Eosinophilic clear cell renal cell carcinoma
  • Chromophobe RCC, eosinophilic
  • Other renal tumors with eosinophilic cytoplasme (SDH deficient renal cell carcinoma)
  • Renal cell carcinoma unclassified
  • Renal oncocytoma