Prostate gland & seminal vesicles

Atypical / intraductal lesions

HGPIN with adjacent atypical glands



Topic Completed: 1 May 2015

Minor changes: 4 September 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: High grade PIN with adjacent small atypical glands

Nicholas P. Reder, M.D., M.P.H.
Maria Tretiakova, M.D., Ph.D.
Page views in 2020: 1,170
Page views in 2021 to date: 1,173
Cite this page: Reder NP, Tretiakova M. HGPIN with adjacent atypical glands. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/prostatePINATYP.html. Accessed December 3rd, 2021.
Definition / general
  • Defined as high grade PIN (HGPIN) with immediately adjacent focus of small atypical glands (Hum Pathol 2001;32:389)
  • More of a diagnostic dilemma than a pathologic entity
Terminology
Prognostic factors
Microscopic (histologic) description
  • Several small atypical glands within 0.01-0.4 mm from HGPIN (0.12 mm on average, Hum Pathol 2001;32:389)
  • The cytologic features of these small atypical glands are similar to adjacent HGPIN, i.e. enlarged nuclei, prominent nucleoli and dark amphophilic cytoplasm
  • It is unclear whether these adjacent small atypical glands represent outpouchings, buddings or tangentially sectioned adjacent HGPIN, or represent a focus of associated infiltrating adenocarcinoma
Microscopic (histologic) images

Contributed by Nicholas P. Reder, M.D., M.P.H.

Arrows point to small atypical glands adjacent to larger HGPIN glands

Negative stains
  • Negative staining for high molecular weight cytokeratin (34βE12) has not been helpful in predicting risk of cancer on repeat biopsy
  • In the seminal study of PINATYP, 2 of 8 patients with negative staining had cancer on repeat biopsy, while 2 of 4 patients with positive staining had cancer on repeat biopsy (Hum Pathol 2001;32:389)
Differential diagnosis
  • HGPIN with budding / tangentially sectioned glands: the atypical glands may fuse with the HGPIN on levels, but the absence of fusion should not be taken as evidence supporting a diagnosis of invasive carcinoma
  • Infiltrative carcinoma between HGPIN glands: can be diagnosed if the small infiltrating glands are too numerous or too far away (> 0.4 mm) from the HGPIN glands
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