Benign Melanotic Lesions of the Cervix
The primary benign melanotic lesions that occur in the cervix are blue nevi (most common at 81% of pigmented cervical lesions), melanotic macules, and melanosis. 1
Blue Nevi
Blue nevi represent the most frequently encountered benign melanocytic lesion of the cervix, with an incidence of approximately 1.2% among women undergoing cervical examination. 1
Clinical Characteristics
- Demographics: Predominantly affect white women (52% of cases) with a mean age of 47.4 years (range 31-64 years) 1
- Location: Always located in the endocervix 1
- Appearance: Number varies from 1-3 lesions per cervix, with sizes ranging from 0.1-2 cm (mean 0.68 cm) 1
Histologic Patterns
Blue nevi of the cervix exhibit three distinct morphologic patterns: 1
- Stromal melanocytic focus (36%): Composed of fine spindle cells
- Mixed pattern (60%): Contains fine spindle, plump spindle, and epithelioid cells
- Nevoid stage (4%): Characterized by epithelioid cells
Melanotic Macule (Lentigo)
Melanotic macules represent a distinct benign melanocytic lesion with different characteristics from blue nevi. 1, 2
Distinguishing Features
- Location: Found in the squamous epithelium of the ectocervix (not endocervix) 1
- Histology: Characterized by hyperpigmentation of basal keratinocytes with scattered slightly enlarged melanocytes 1
- Clinical significance: Represents benign lentigo of the uterine cervix, providing evidence that the cervix can form the entire spectrum of melanocytic lesions known in skin 2
Cervical Melanosis
Melanosis is an extremely rare benign melanocytic lesion with only approximately 11-14 cases reported in the English literature. 3, 4
Pathologic Features
- Histology: Demonstrates hyperkeratosis, acanthosis, and prominent elongation of rete ridges with abundant basilar pigmentation 3
- Immunohistochemistry: Shows scattered, basally situated, S-100 protein-positive melanocytes 3
- Clinical behavior: Appears to be innocuous and typically discovered incidentally 4
Important Clinical Considerations
Diagnostic Approach
Biopsy is essential to distinguish benign melanotic lesions from malignant melanoma of the cervix, which though rare, carries an extremely poor prognosis. 4, 5 Deeper histologic levels may be required for detection and to definitively exclude cervical melanoma. 1
Incidence and Detection
The overall incidence of grossly visible pigmented cervical lesions is approximately 1.6%, with 97% having a histologic correlate upon examination. 1 Of these, approximately 88% (26/32 cases with histologic correlate) are melanocytic in nature. 1
Differential Diagnosis
Non-melanocytic pigmented lesions that may mimic benign cervical melanosis include: 1
- Biopsy site-associated reactive changes with hemosiderin-laden macrophages (6.4%)
- Hemorrhagic Nabothian cysts (3%)
- Hemangiomas (3%)
- Focal granulomatous vasculitis (3%)