Intradermal nevus

Intradermal nevus
Diagnosis in short
Intradermal nevus. H&E stain.
Synonyms	intradermal melanocytic nevus
LM	nests of melanocytes in dermis (only), melanocytes "mature" with depth, usu. no mitoses (occ. superficial), no destruction of surrounding structures, no conspicuous nucleoli, no significant melanocyte enlargement
LM DDx	malignant melanoma (nevoid), junctional nevus, compound nevus, dysplastic nevus, skin tag
Gross	pigment skin lesion, usu. small, regular border, no irregularity in pigmentation
Site	skin - see melanocytic lesions and common nevus
Prevalence	very common
Prognosis	benign
Clin. DDx	pigmented skin lesions
Treatment	none required, may be excised for cosmetic reasons

Intradermal nevus (abbreviated IDN), also intradermal melanocytic nevus, is a common benign melanocytic lesion.

The intradermal nevus is in the large group common nevus. In common language, nevus is known as a mole.

In the oral cavity these are known as intramucosal nevi.

General

• Benign.
• Common.
• Think melanoma.

Clinical:

• ABCD = asymmetric, borders (irregular), colour (black), diameter (large).

Microscopic

Features:

• Symmetrical lesion.
• "Matures" with depth.
  • Less cellular with depth.
  • Less nuclear atypia with depth.
  • Smaller cells with depth.
  • Smaller nests with depth.
• Rare mitoses (superficial).
  • No deep mitoses.
• No destruction of surrounding structures.
• No nucleoli.
• In the dermis only - key feature.
• +/-Adipocytes - uncommon.

DDx:

• Malignant melanoma (nevoid).
• Dysplastic nevus.
• Junctional nevus.
• Compound nevus.
• Skin tag.

Images

• 

  IDN - very low mag.

• 

  IDN - low mag.

• 

  IDN - intermed. mag.

• 

  IDN - high mag.

• 

  IDN - very high mag.

See also

• Melanocytic lesions.