Kidney tumor
Renal pelvis: Urothelial carcinoma and variants
Urothelial carcinoma of renal pelvis - microcystic variant


Topic Completed: 1 December 2015

Revised: 18 September 2019

Copyright: 2003-2019, PathologyOutlines.com, Inc.

PubMed Search: Urothelial carcinoma microcystic

Related Topic: Urothelial carcinoma of renal pelvis

Nicole K. Andeen, M.D.
Maria Tretiakova, M.D., Ph.D.
Page views in 2018: 148
Page views in 2019 to date: 159
Cite this page: Andeen NK, Tretiakova M. Microcystic variant. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneytumormalignanturothelialcarcinomasubtypesmicrocystic.html. Accessed November 14th, 2019.
Definition / general
  • Invasive urothelial carcinoma with deceptively bland architecture and cytology, consisting of slit-like or tubular microcysts lined by cuboidal / flattened cells with minimal atypia and intraluminal granular eosinophilic material (Mod Pathol 2009;22:S96)
  • Given overall rarity and similarities with microcystic urothelial carcinoma of the bladder, some information and pictures are extracted from bladder, where appropriate
Essential features
  • Very rare
  • Main biologic significance is deceptively benign features, which may be mistaken for cystitis cystica or glandularis on small biopsies, but is usually deeply invasive
  • Histologically may be distinguished by infiltrative growth pattern and variability in cyst size / shape
Terminology
Epidemiology
  • < 20 cases reported in genitourinary tract including 3 in renal pelvis
Sites
  • Bladder, renal pelvis
Clinical features
  • Usually deeply invasive
Prognostic factors
Case reports
Treatment
  • No consensus established
Microscopic (histologic) description
  • Invasive urothelial carcinoma with slit-like or tubular microcysts, lined by single to multilayered cuboidal or flattened cells with minimal cytologic atypia
  • Microcysts are irregular in size / shape, and deeply infiltrative
  • Has luminal granular eosinophilic secretions with necrotic cellular debris, sometimes mucinous material or a targetoid appearance (PAS+, Alcian blue+) (Mod Pathol 2009;22:S96, Arch Pathol Lab Med 2007;131:1244)
  • May be focally calcified
  • May be associated with nested variant of urothelial carcinoma
Microscopic (histologic) images

Contributed by Nicole K. Andeen, M.D. and Maria Tretiakova, M.D., Ph.D.

Deceptively bland urothelial carcinoma composed of infiltrative, microcystic/tubular structures

Deep muscular invasion

CK7 highlights invasive nests

Microcystic and nested features



Images hosted on other servers:
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Cysts of various sizes

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Neoplastic cystic structures

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Cuboidal or flattened cells

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Eosinophilic secretions

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Low grade UC

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Microcystic variant

Positive stains
Negative stains
Differential diagnosis
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