Kidney tumor
Adult renal cell carcinoma
Hybrid oncocytic / chromophobe tumor


Topic Completed: 1 September 2015

Revised: 5 March 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Hybrid oncocytic chromophobe tumor

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Cite this page: Guilmette J, Albadine R. Hybrid oncocytic / chromophobe tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneytumoroncocyticchromhybrid.html. Accessed July 23rd, 2019.
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
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 description
Prognostic factors
Case reports
Treatment
Gross description
Microscopic (histologic) description
  • Noninfiltrative, 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

Case of the Week #379

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CD117

E-cadherin

Hale colloidal iron



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Contributed by Chin-Lee Wu, Ph.D., Harvard School of Medicine:
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Dual population of eosinophilic cells



Contributed by 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

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Hale colloidal iron

Cytology description
Positive stains
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
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