Pathology Associates Of Lexington, P.A.

Pathology Associates Of Lexington, P.A.

Pathology Associates Of Lexington, P.A.

Nevoid Maignant Melanoma (NMM)

The big deal here is to not overlook "NMM, small cell" during a busy day of routine surgical sign-outs.

Similarities:

NMM, small cell	Nevus
Cells tend to be small	Cells tend to be small
Pagetoid cells are rare	Pagetoid cells are rare
Melanocytes are nested	Melanocytes are nested
Cells may disperse at base	Cells disperse at base

NMM, large cell	Spitz Nevus
Cells tend to be large	Cells tend to be large
Pagetoid cells may be present	Pagetoid cells may be present
Melanocytes are nested	Melanocytes are nested
Cells may disperse at base	Cells disperse at base

Differences:

NMM, small cell	Nevus
Mitoses present in dermis	Mitoses absent in dermis
Nucleoli visible at base	Nucleoli inconspicuous at base
Nuclei hyperchromatic & hyperchromatic, with oval	Nuclei not very angulated at base to spindle shape at base
Pigmentation sparse	Pigmentation rare at base, present at base
HMB-45 positive at base	HMB-45 negative at base
Ki67 positive at base	Ki67 negative at base

NMM, large cell	Spitz Nevus
Mitoses present in dermis even at the base	Mitoses present in dermis but rarely at the base
Cell size large at base	Cell size small at base
Few Kamino bodies	Kamino bodies are common
Epidermal hyperplasis may be present	Epidermal hyperplasia is frequent
HMB-45 positive at base	HMB-45 patchy positivity and may be at base
Ki67 undimished at base	Ki67 diminishesto base

[posted 29 July 2005]

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