Variant morphology in upper urinary tract urothelial carcinoma: a 14-year case series of biopsy and resection specimens

Hiroyuki Hayashi, Steven Mann, Chia sui Kao, David Grignon, Muhammad T. Idrees

Research output: Contribution to journalArticle

6 Scopus citations


Upper urinary tract urothelial carcinoma exhibiting variant morphology, especially in higher-grade tumors, is a recognized phenomenon but has not been comparatively studied in biopsy versus resection material. We studied the morphologic patterns and clinicopathological features, and provide a comparison between biopsy and resection specimens. Consultation cases were evaluated separately to investigate for possible consultation bias. A total of 383 in-house cases from 352 patients including 314 resection specimens and 69 biopsies from 2001 to 2014 were reviewed from a single institution. Histologic type, tumor grade, invasion, pathologic stage, nodal status, metastasis, and the presence and type of variant morphology for each case were evaluated. Variant morphology was identified in 5 biopsy specimens (7.2%) and 42 resection specimens (13.4%). The most common variant morphologic pattern was squamous differentiation (16 cases, 4.5%) followed by an inverted growth pattern (8 cases, 2.2%). The presence of variant morphology in resection specimens had a significant association with higher tumor grade, higher pT stage, and nonpapillary configuration. Of 69 patients with biopsies, 31 had a subsequent resection. In comparison, 181 consultation cases from 168 patients showed variant morphology in 6 biopsies (7.1%) and 27 resections (28.1%). In conclusion, the frequency of recognizing variant morphology in biopsies is about one-half of that in resections. The inclusion of consultation cases can inflate the incidence of variant morphology. As a result, the frequency of variant morphology in our in-house cases is lower than the percentage reported in the literature, most likely secondary to a consultation bias.

Original languageEnglish (US)
Pages (from-to)209-216
Number of pages8
JournalHuman pathology
StatePublished - Jul 2017


  • Inverted growth pattern
  • Squamous differentiation
  • Upper urinary tract
  • Urothelial carcinoma
  • Variant morphology

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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