Table of Contents
Definition / general | Microscopic (histologic) description | Microscopic (histologic) images | Definition / general | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosis | Definition / general | Microscopic (histologic) description | Positive stains | Differential diagnosis | Additional referencesCite this page: Perunovic B. SIL variants. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cervixSILvariant.html. Accessed March 9th, 2021.
Atypical immature metaplasia
Definition / general
- Controversial term not accepted by most gynecologist pathologists
- Poorly reproducible diagnosis which lacks a uniform definition; spans a morphologic spectrum and includes many diagnostically challenging cases with an immature appearance
- 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
- HPV+ cases are associated with future diagnosis of HSIL
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
Condyloma-immature
Definition / general
- Also called papillary immature metaplasia, immature exophytic LSIL, squamous papilloma
- Considered a variant of LSIL
- Infection of transformation zone epithelium that fails to mature, maintains a phenotype resembling immature metaplasia
- Involves proximal transformation zone and endocervix
- Strongly associated with HPV subtypes 6 and 11 (Mod Pathol 1992;5:391)
Treatment
- Excisional biopsy, diathermy or laser vaporization
Microscopic (histologic) description
- Patterns of immature condyloma include:
- Close similarity to squamous metaplasia with
- Mild increases in nuclear cytoplasmic ratio
- Preservation of nucleoli
- Slight nuclear crowding
- A near absence of keratinocyte maturation
- Formation of small slender filiform papillae (pathognomic)
- Frequent preservation of overlying columnar cells
- No / rare mitotic figures
- Close similarity to squamous metaplasia with
Microscopic (histologic) images
HSIL with immature metaplastic dysplasia
Differential diagnosis
- Air drying artifact
- Papillary immature metaplasia: papillary not flat, less nuclear pleomorphism and atypia
HSIL with eosinophilic dysplasia
Definition / general
- Present in 10% of HSIL lesions
- Associated with HPV infection and classic HSIL in adjacent areas
- May arise from metaplastic cervical squamous epithelium that has become infected with high risk HPV
Microscopic (histologic) description
- Lack of normal maturation
- Compared to classic HSIL, cells have distinct cell borders and abundant eosinophilic cytoplasm, increased N/C ratio and focal dysplastic nuclei with nuclear enlargement, hyperchromasia, variable nuclear membrane abnormalities and distinct nucleoli
- Associated with classic SIL and squamous metaplasia
Differential diagnosis
Additional references