Amelanotic melanomas lack some or all pigment and can be extremely difficult to identify.
The ICD-O classification includes further morphological codes, such as balloon cell M, regressing M,
amelanotic M, M in junctional nevus, M in precancerous melanosis, desmoplastic M, neurotropic M, mucosal lentiginous M, M in giant pigmented nevus/congenital melanocytic nevus, mixed epithelioid and spindle cell M, epithelioid cell M, spindle cell M (not otherwise specified), spindle cell M (type A), spindle cell M (type B), and malignant blue nevus (3).
(6,16) Importantly, these observations allow for meaningful comparison with potential metastases, which are often
amelanotic. (9)
[2] Virtually
amelanotic examples may be encountered but are exceptional.
Keywords: Pedunculated melanoma,
amelanotic melanoma, melanoma.
Immunohistochemical staining for S100 protein in the diagnosis of canine
amelanotic melanoma.
However, the best treatment modality is excision.[5,9,10]
Amelanotic melanoma and SCC should be considered for the differential diagnosis.[9]
A modified ABCDE for pediatric melanoma has been proposed:
amelanotic, bump/bleeding, color uniformity, diameter variability, de novo, and evolution.
(1,2,3) It manifests with a painless melanotic or
amelanotic mass on the ocular surface and is usually accompanied by a persistent dilated feeder blood vessel.
Mortimer, "Aggressive
amelanotic lentigo maligna," British Journal of Dermatology, vol.
examined ALP immunoreactivity of 61 cytopathology samples from canine, consisting of 33 OSAs, 4 chondrosarcomas, 4 synovial sarcomas, 2 fibrosarcoma, 9 soft tissue sarcomas, 2 plasma cell tumours, 2 lymphomas, 2
amelanotic melanomas, 2 mast cell tumours, and 1 multilobular tumour (MLT) of bone, which showed sensitivity and specificity of 100% and 89% [13].