What are the histologic features of cervical cancer?

Histologic Features of Cervical Cancer

Cervical cancer exhibits two major histologic types—squamous cell carcinoma (most common) and adenocarcinoma—each with distinct microscopic features and multiple subtypes that guide pathologic reporting and clinical management. 1

Major Histologic Types

Squamous Cell Carcinoma

Squamous cell carcinoma comprises the majority of cervical cancers and is classified into several subtypes based on morphologic features 1:

Keratinizing Type:

• Requires the presence of keratin pearls as a defining feature
• Shows squamous differentiation with keratinization

Nonkeratinizing Type:

• Demonstrates a wide morphologic spectrum including:
  • Individual cell keratinization without pearl formation
  • Tumor cells with clear cytoplasm
  • Tumor cells with eosinophilic cytoplasm and distinct cell borders
• May be further subdivided into large cell and small cell variants (optional classification) 1

Variant Subtypes:

• Verrucous carcinoma
• Warty (condylomatous) carcinoma
• Papillary squamous cell (transitional) carcinoma
• Lymphoepithelioma-like carcinoma 1

Important Note: Histopathologic grading of squamous cell carcinoma using traditional systems (including the Broders modification) fails to correlate reliably with prognosis, making grading optional 1.

Adenocarcinoma

Adenocarcinomas are graded using both architectural and cytologic (nuclear) criteria based on the percentage of solid growth 1:

Grade 1 (Well-Differentiated):

• ≤10% solid growth
• Well-formed regular glands with papillae
• Elongate, columnar cells with uniform oval nuclei
• Minimal stratification (<3 cell layers thick)
• Infrequent mitotic figures

Grade 2 (Moderately Differentiated):

• 11-50% solid growth
• Complex glands with frequent bridging and cribriform formation
• More rounded and irregular nuclei with micronucleoli
• More frequent mitoses

Grade 3 (Poorly Differentiated):

• 50% solid growth

• Sheets of malignant cells with few discernible glands
• Large, irregular cells with pleomorphic nuclei
• Occasional signet cells
• Abundant mitoses with abnormal forms
• Pronounced desmoplasia and common necrosis 1

Adenosquamous Carcinoma

This mixed tumor type contains both glandular and squamous elements and is recognized as a distinct entity in the NCCN guidelines 2.

Critical Pathologic Features for Reporting

Depth of Invasion

Maximum depth of stromal invasion must be measured in millimeters from the point of origin 1:

Microinvasive Carcinoma Classification:

• SGO criteria: ≤3 mm invasion from point of origin without angiolymphatic space invasion
• FIGO criteria: ≤5 mm invasion and ≤7 mm in greatest horizontal dimension
• Only invasive carcinoma should be measured (exclude in situ component) 1

Lymphovascular Space Invasion (LVSI)

LVSI is a critical prognostic feature that affects staging and treatment decisions. Research demonstrates that adenocarcinoma shows less LVSI (26.7%) compared to squamous cell carcinoma (37.9%) 3.

Additional Important Features

• Stromal invasion depth (proportion of cervical wall involved)
• Margin status (particularly for cone biopsies—preferably 3-mm negative margins)
• Peripheral nerve infiltration (more common in adenosquamous carcinoma at 15.4% vs 5.7% in adenocarcinoma) 3

Precursor Lesions

The guidelines recognize a spectrum of preinvasive disease 1:

Squamous Intraepithelial Lesions (SIL):

• CIN 1 (mild dysplasia) = Low-grade SIL
• CIN 2 (moderate dysplasia) = High-grade SIL
• CIN 3 (severe dysplasia/carcinoma in situ) = High-grade SIL

Glandular Lesions:

• Endocervical glandular atypia
• Glandular dysplasia
• Adenocarcinoma in situ (normally situated glands lined by cytologically malignant epithelium) 1

Prognostic Implications

Histologic type significantly impacts prognosis. Recent research demonstrates that adenocarcinoma and adenosquamous carcinoma have substantially worse outcomes than squamous cell carcinoma 3:

• 5-year recurrence-free survival: Squamous 85.1% vs Adenocarcinoma 78.2% vs Adenosquamous 72.3%
• 5-year overall survival: Squamous 89.7% vs Adenocarcinoma 83.1% vs Adenosquamous 79.6%
• Both adenocarcinoma and adenosquamous types are independent prognostic factors for worse survival (HR 2.594 and 2.105 respectively for recurrence-free survival) 3

Clinical Caveats

Important exclusions: Small cell neuroendocrine carcinomas (which show neuroendocrine differentiation by immunohistochemistry and ultrastructure), glassy-cell carcinomas, and sarcomas are not covered by standard cervical cancer guidelines and require different management approaches 2.

Adenocarcinoma detection challenges: Cervical cytologic screening is less effective for adenocarcinoma because adenocarcinoma in situ affects the endocervical canal, which is harder to sample adequately 2.