A final possibility, which is the least likely, is that the few nevus cells
left behind transformed into melanoma."
The histological criteria of typical MN were the presence of nests of melanocytes / nevus cells
that are distributed at the dermoepidermal junction (junctional nevus), confined to the dermis (intradermal nevus), or with both components Atypical histological features included poor circumscription, asymmetry, irregular confluent nests, predominance of single melanocytes, cytological atypia, frequent mitosis, and presence of necrosis (7).
Blinded enumeration was performed under light microscopy at 400x magnification, and an ocular grid consisting of a simple square lattice of 100 test points was utilized to count the number of positively and negatively stained melanomas or nevus cells
for each section.
Pigmented cellular nevus is benign proliferation of the nevus cells
either in the epithelium or connective tissue and is categorized as hamartoma or developmental malformation.
Heterotopic inclusions Lymph nodes commonly involved Breast tissue Axillary Aggregate of nevus cells
Axillary Blue nevus Axillary Squamous epithelium Cervical and peripancreatic Salivary gland tissue Cervical Thyroid follicles Cervical Decidual tissue Pelvic Epithelium of paramesonephricus type Pelvic Intestinal glands Mesenteric Mesothelial cells Mediastinal and retroperitoneal Pantanowitz & Upton, 2003.
The initial pathology diagnosis of dysplastic nevus might have been wrong and the lesion may have been a melanoma from the start, the focus of the melanoma within a dysplastic nevus could have been missed, or a melanoma could arise from residual dysplastic nevus cells
. It is best to eliminate doubt by completely excising dysplastic nevi slated for biopsy," Dr.
Many times such a nevus fades as the child ages, not because it regresses but because the nail matrix nevus cells
reduce the production of melanin.