History

R.S. is a 38-year-old white male who presents to his PCP after his wife noticed a suspicious-looking, dark brown mole in his scalp while giving him a haircut. He was referred to your clinic. He has a history of lipoma over the left ribcage, surgically removed 10 years ago with no recurrence. He reports an episode of major depression with suicidal tendencies eight years ago, treated successfully with an antidepressant and psychotherapy for 10 weeks with no recurrence.

ROS

No changes in vision, smell, or hearing.
No headaches, cough, fever, chills, night sweats, nausea, or vomiting.
No changes in bowel or bladder habits.
No fatigue or weakness.
SKIN

Fair complexion with multiple scattered nevi on the back.
Negative for rashes and other lesions.
Warm to the touch and slightly diaphoretic.
Normal distribution of body hair.
HEENT

7-mm nodule on the scalp above the right ear, dome-shaped, symmetric, dark brown in color, no variations.
PERRLA.
EOMI.
Funduscopic WNL.
Normal sclera.
TMs intact.
Mucous membranes moist.
Throat without lesions, edema, exudates, or erythema.
Poor dentition, several fractured teeth.
Biopsy

An excisional biopsy of the mole showed cells consistent with that of nodular melanoma. Tumor thickness was 3.8 mm. Cervical nodes were enlarged and measured 2.3 and 2.7 cm. A CT scan of the thorax was negative. With the exception of questionable shadows in the liver, the abdominal CT scan was also negative. A CT scan of the brain was clearly positive for 3 lesions.

Laboratory Blood Test Results

Na = 142 meq/L
Cr = 0.6 mg/dL
WBC = 7,200/mm3
AST = 115 IU/L
K = 4.5 meq/L
RBC = 5.3 million/mm3
ALT = 145 IU/L
Hct = 43%
Glu, fasting = 103 mg/dL
Mg = 2.7 mg/dL
HCO3 = 31 meq/L
Cl = 103 meq/L
Bilirubin, total = 1.7 mg/dL
PO4 = 4.4 mg/dL
Ca = 10.3 mg/dL
BUN = 14 mg/dL
Alb = 3.5 g/dL
Alk phos = 278 IU/L
Plt = 239,000/mm3
Hb = 16.3 g/dL
Questions

Why is the lack of clinical manifestations in the ROS above significant?
Based on this rather limited information provided under History, ROS, SKIN, and HEENT above, which subtype of melanoma is most likely?
Are any of the laboratory blood test results above abnormal and, if so, what is suggested by the abnormality?
What is the current probability that this patient will be alive in 10 years?