Pathology of Deep Penetrating Nevus

"A benign pigmented tumour which should

not be mistaken for melanoma".

Dr Sampurna Roy MD     

Deep penetrating nevus is a distinct form of melanocytic nevus and may mimic various pigmented lesions.

This lesion has distinct microscopic features which helps in excluding melanoma and establishing the correct diagnosis.

Clinically, the lesion usually occurs on the head and neck region and presents as darkly pigmented papule or nodule.

Many authors regard this lesion as a variant of blue nevus.    

The most important differential diagnosis is Melanoma.

The following features helps in establishing the diagnosis:

1.  Melanoma of the thickness of deep penetrating nevus usually displays  marked cellular and architectural atypia.

2.  In deep penetrating nevus there is no pagetoid intraepidermal spread. 

3.  There is no irregular epidermal acanthosis or thinning.

4.  No irregular fibroinflammatory dermal response is seen in deep penetrating nevus.

5.  Proliferating cell nuclear antigen (PCNA) is present in scattered melanocytes (less than 5%) in the deep penetrating nevus.

In melanoma 25%-75% cells show immunopositivity with PCNA.

The differential diagnosis also include Spitz nevus ; congenital melanocytic nevus.      

Dermatopathology Quiz Case 137  

Deep penetrating nevus: a case report and brief literature review.

Deep penetrating (plexiform spindle cell) nevus

Linear arrangement of multiple deep penetrating nevi: report of first case and review of literature

Proliferating cell nuclear antigen staining in deep-penetrating nevi

Deep penetrating nevus: a review

An unconventional deep penetrating melanocytic nevus with microscopic involvement of regional lymph nodes

Deep penetrating (plexiform spindle cell) nevus. A frequent participant in combined nevus.

Deep penetrating nevus.