Clincal: Melanocytic Tumors Flashcards
What evaluation should be done in patients with large congenital nevi with satellite lesions?
Order an MRI
-these patients are at risk of cranial or leptomeningial melanocytosis (melanocytic tumors in the arachnoid and pia mater)
-remember melanocytes form from neural crest cells, so it is possible that some melanocytes formed in the CNS
What are benign acquired nevi?
Moles
-usually one color, symmetric, small
What are dysplastic nevi?
Moles with some clinically atypical features (shape, color, borders)
What is a Spitz Nevus?
Melanocytic lesion that usually occurs in kids. Histology is similar to melanoma
Gross morphology of melanoma
Tumor of melanocytes with asymmetrical shape, irregular borders, multiple colors, larger 6mm diameter, rapidly evolving
How is melanoma differentiated from dysplastic nevi?
Pathological biopsy
- grossly they look the same
- a dysplastic nevus NEVER turns into a melanoma however a melanoma can arise from tissue among or in close proximity to a nevus
Most common subtype of melanomas
Superficial Spreading Melanoma
-slowly spreading and changing lesion over years
Most aggressive subtype of melanoma
Nodular Melanoma
-rapidly evolving black or blue-red uniform nodule
What is Lentigo Maligna?
Melanoma due to chronic sun exposure
-usually starts as macular or patchy (flat) hyperpigmented growth
What is Acral Lentiginous Melanoma?
Melanoma on the hands and feet
- most common in African, African American, Asian descent
- poor prognosis because diagnosis is usually delayed
What is Amelanotic Melanoma?
Melanoma without pigment, so it looks more like basal cell or squamous cell carcinoma
Gold standard for melanoma diagnosis
Histopathology
Why do skin biopsies suspected of being melanoma need to be removed all the way down to the subQ fat layer?
Depth of the primary lesion determines staging and prognosis (Breslow Thickness)
What is a sentinel lymph node biopsy
Method of using irradiated dye to follow lymphatic flow of a suspicious lesion to the nearest lymph node. Useful if lymph nodes need to be removed.
Treatment for melanoma
Complete lesional excision and lymph node dissection if necessary
