The investigators propose the use of functional photoacoustic microscopy (fPAM) to evaluate both benign and malignant pigmented lesions for tumor depth. Through fPAM analysis followed by histological examination, the investigators anticipate that they will be able to non-invasively determine tumor depth of pigmented lesions (moles and melanoma). In melanoma, tumor depth (Breslow's depth) is not only an important prognostic indicator, but also directs surgical treatment. The ultimate goal is to develop a sensitive clinical tool that will allow non-surgical evaluation of pigmented lesions, which eventually, will aid in melanoma diagnosis and management - potentially an earlier and more definitive surgical management.

In addition, the investigators propose to use the combination of fPAM and single-cell PAM to respectively image CTCs in trunk vessels and cuticle capillaries. Based on the investigators' murine models, the investigators anticipate that they will be able to differentiate CTCs from other blood cells and reliably calculate CTC concentration in a non-invasive manner. CTC concentration has been demonstrated to be a valuable indicator of a melanoma's metastatic potential and a potential tool in evaluating treatment efficacy. The ultimate goal is to develop a sensitive imaging device that will allow accurate evaluation of the risk of melanoma recurrence and metastases, that may facilitate treatment monitoring.

Inclusion Criteria:

Outcome Measure #1 and #2

• Healthy individuals with pigmented lesions or a partially biopsied melanoma whose treatment plan includes excision
• Participants must be 18 years or older
• Participants must be able to understand and willing to sign a written informed consent document

Outcome Measures #3 and #4

• Patients with either cutaneous, visceral or brain melanoma metastases.
• Participants must be 18 years or older.
• Participants must be Eastern Cooperative Oncology Group (ECOG) status 0-3.
• Participants must be able to understand and willing to sign a written informed consent document.

Exclusion Criteria:

• Minors, pregnant patients, incarcerated individuals, and individuals unable to give informed consent will be excluded from this study
• ECOG status > 3