Desmoplastic melanoma
Melanoma with small nevus-like cells
Melanoma with features of a Spitz nevus
Uveal melanoma
Vaginal melanoma
Polypoid melanoma, a subclass of nodular melanoma. In situ or invasive
A melanoma in situ has not invaded beyond the basement membrane, whereas an invasive melanoma has spread beyond it. Some histopathological types of melanoma are inherently invasive, including nodular melanoma and lentigo maligna melanoma, where the in situ counterpart to lentigo maligna melanoma is lentigo maligna. Lentigo maligna is sometimes classified as a very early melanoma, and sometimes a precursor to melanoma.Superficial spreading melanomas and acral lentiginous melanomas can be either in situ or invasive, but acral lentiginous melanomas are almost always invasive. Staging
Further context on cancer staging is available at TNM. Metastatic melanomas can be detected by X-rays, CT scans, MRIs, PET and PET/CTs, ultrasound, LDH testing and photoacoustic detection. However, there is lack of evidence in the accuracy of staging of people with melanoma with various imaging methods.Melanoma stages according to AJCC, 8th edition:
TX: Primary tumor thickness cannot be assessed (such as a diagnosis by curettage)
T0: No evidence of primary tumor (such as unknown primary or completely regressed melanoma)Stage 1 and 2 require an N (lymph node) class of:

N0 – No regional metastases.Stage 1, 2 and 3 require an M (metastasis status) of:

M0: No evidence of distant metastasisOlder systems include "Clark level" and "Breslows depth", quantifying microscopic depth of tumor invasion.
A 2009 meta-analysis of randomized controlled trials found a small difference in survival rates favoring wide excision of primary cutaneous melanomas, but these results were not statistically significant.Mohs surgery has been reported with cure rate as low as 77% and as high as 98.0% for melanoma-in-situ. CCPDMA and the "double scalpel" peripheral margin controlled surgery is equivalent to Mohs surgery in effectiveness on this "intra-epithelial" type of melanoma. Melanomas that spread usually do so to the lymph nodes in the area of the tumor before spreading elsewhere. Attempts to improve survival by removing lymph nodes surgically (lymphadenectomy) were associated with many complications, but no overall survival benefit. Recently, the technique of sentinel lymph node biopsy has been developed to reduce the complications of lymph node surgery while allowing assessment of the involvement of nodes with tumor.Biopsy of sentinel lymph nodes is a widely used procedure when treating cutaneous melanoma.Neither sentinel lymph node biopsy nor other diagnostic tests should be performed to evaluate early, thin melanoma, including melanoma in situ, T1a melanoma or T1b melanoma ≤ 0.5mm. People with these conditions are unlikely to have the cancer spread to their lymph nodes or anywhere else and have a 5-year survival rate of 97%. Because of these considerations, sentinel lymph node biopsy is considered unnecessary health care for them. Furthermore, baseline blood tests and radiographic studies should not be performed only based on identifying this kind of melanoma, as there are more accurate tests for detecting cancer and these tests have high false-positive rates.