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.
Cholic acid, also known as 3α,7α,12α-trihydroxy-5β-cholan-24-oic acid is a primary bile acid that is insoluble in water (soluble in alcohol and acetic acid),  it is a white crystalline substance. Salts of cholic acid are called cholates. Cholic acid, along with chenodeoxycholic acid, is one of the two major bile acids produced by the liver, where it is synthesized from cholesterol. These two major bile acids are roughly equal in concentration in humans. Derivatives are made from cholyl-CoA, which exchanges its CoA with either glycine, or taurine, yielding glycocholic and taurocholic acid, respectively.Cholic acid downregulates cholesterol-7-α-hydroxylase (rate-limiting step in bile acid synthesis), and cholesterol does the opposite. This is why chenodeoxycholic acid, and not cholic acid, can be used to treat gallstones (because decreasing bile acid synthesis would supersaturate the stones even more).Cholic acid and chenodeoxycholic acid are the most important human bile acids. Other species may synthesize different bile acids as their predominant primary bile acids. Medical uses
Cholic acid, sold under the brand name Cholbam, is approved for use in the United States and is indicated as a treatment for children and adults with bile acid synthesis disorders due to single enzyme defects, and for peroxisomal disorders (such as Zellweger syndrome).It was approved for use in the European Union in September 2013, and is sold under the brand name Orphacol.