Cervix
Premalignant / preinvasive lesions
Atypical immature metaplasia

Author: Seema Khutti, M.D. (see Authors page)

Revised: 21 April 2017, last major update October 2013

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Atypical immature metaplasia [title]
Cite this page: Atypical immature metaplasia . PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cervixatypicalimmaturemetaplasia.html. Accessed July 27th, 2017.
Definition / general
  • First described by Crum et al (Cancer 1983;51:2214) as a low grade lesion but now often includes both high grade and low grade lesions
  • Currently is a poorly reproducible diagnosis which lacks a uniform definition; spans a morphologic spectrum and includes many diagnostically challenging cases with an immature appearance
  • HPV+ cases are associated with future diagnosis of HSIL
Sites
  • Squamous proliferation of transformation zone and endocervical glands associated with abnormal Pap smears and a colposcopically visible abnormality
Treatment
  • Based on size and distribution of lesion
Microscopic (histologic) description
  • More cellular than usual immature squamous metaplasia
  • Nonpapillary, metaplastic squamous epithelium with nuclear atypic
  • Basal layer of uniform cells with a uniform chromatin pattern and variable hyperchromasia
  • Overlying squamous cells are monomorphic with prominent chromocenters and regular nuclear membranes
  • Normal cell polarity, rare / no cell crowding
  • Mitoses are < 1 per 10 HPF, normal (not atypical) and confined to lower third of epithelium
  • Occasionally higher mitotic rates, multinucleation, nuclear enlargement and perinuclear halos
Microscopic (histologic) images

Images hosted on other servers:

Atypical immature metaplasia

Subcategories

Atypical immature metaplasia


Use of immunostains to reclassify atypical immature metaplasia

Cytoplasmic CK17

HSIL / CINIII

HSIL

Positive stains
Reporting method
  • Atypical immature metaplasia is not commonly used as a diagnostic term in surgical pathology reports
  • Soslow et al. currently use diagnosis of HSIL if diffusely p16+ and hyperproliferative based on Ki67 (Arch Pathol Lab Med 2009;133:729)
  • HPV+, p16+ hypoproliferative lesions with Ki67+ may be early or regressing lesions
  • If immunostains do not support a proliferative, HPV associated lesion, diagnosis often includes explanatory note
Molecular / cytogenetics description
Differential diagnosis