Urinary excreion of DOPA and metabolites by patients with melanoma

A Qualitative Gas Chromatographic Analysis of Substituted 5,6-Dihydroxyindoles from the Urine of Patients with Melanoma

A qualitative gas chromatographic analysis of trimethylsilylated ethyl acetate extracts of melanotic urine revealed 5 indolic compounds, which have been identified as substituted 5,6-dihydroxyindoles. Ethyl acetate extracts of melanotic urines at pH 2.0 contained isomeric 5-hydroxy-6-methoxy and 6-hydroxy-5-methoxy-indolyl-2-carboxylic acids which were not separable under the conditions used. A careful hydrolysis of melanotic urine with a Helix pomatia preparation followed by extraction at pH 6.5 in a nitrogen atmosphere released 3 additional indolic compounds from their conjugated form. Using gas chromatographic-mass spectrometric analysis they were identified as 5-hydroxy-6-methoxy, 6-hydroxy-5-methoxyindole and 5,6-dihydroxyindole.

Adrenal malignant melanoma masquerading as a pheochromocytoma in a patient with a history of a multifocal papillary and medullary thyroid carcinoma

OBJECTIVE

Adrenal masses usually represent benign and nonfunctional adrenal adenomas; however, primary or metastatic malignancy should also be considered. Discovery of an adrenal mass needs further evaluation in order to exclude malignancy and hormonal secretion. We present a rare case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a pheochromocytoma.

CASE REPORT

A 61-year-old male farmer was referred for evaluation of a mass in the right supraclavicular region and a left adrenal lesion. The patient had a history of a multifocal papillary and medullary thyroid carcinoma. Laboratory tests revealed increased 24hour urinary dopamine and also increased serum calcitonin and neuron specific enolase. A pathology report of the resected right supraclavicular mass and left adrenal showed a malignant melanoma.

CONCLUSION

This is a case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a pheochromocytoma. Although this case is very rare and there are rigid diagnostic criteria for the diagnosis of primary adrenal melanoma, it underlines the fact that the differential diagnosis of a dopamine secreting adrenal mass should include primary or metastatic malignant melanoma in order to determine the best diagnostic approach for the patient and select the most appropriate surgical management.

Melanin pigments and melanosomal proteins as differentiation markers unique to normal and neoplastic melanocytes

This report introduces some aspects of our current basic research focus on the unique metabolic pathways within the melanocyte. Using this approach, we hope to gain a better understanding of the pathophysiology of malignant melanoma and develop early laboratory diagnostic tests for this disease. Specifically, we will discuss that: 1) the synthesis of pheomelanin is markedly increased in malignant melanoma and dysplastic melanocytic nevi; 2) high levels of metabolites of pheomelanin and eumelanin can be detected in the urine and blood of patients with metastatic melanoma; 3) this release of melanin metabolites appears to correlate with tumor thickness and tumor load, including the extent of metastasis; 4) the synthesis of melanosomal proteins also becomes aberrant in malignant melanoma; and 5) this abnormal melanosome synthesis can be utilized in the identification of antigenic epitopes that are uniquely expressed in malignant melanoma. We believe that this synthesis and secretion of abnormal melanin pigment and melanosomal proteins (human melanosome-specific antigen) would be useful for the development of early laboratory diagnostic and monitoring tools for malignant melanoma. In addition, we also report the detection of pheomelanin component in "normal" unexposed skin; however, the relative amount of pheomelanin in the skin does not reflect hair color (e.g., red hair). The nature of this pheomelanin component in the skin needs to be further clarified.

Role of the clinical laboratory in the diagnosis and management of malignant melanoma

The biosynthesis of melanin from tyrosine is reviewed as the basis for assessment of laboratory tests that might potentially aid in the diagnosis and management of patients with malignant melanoma. These tests include qualitative and quantitative assays for the intermediates in metabolism of melanin and catecholamines, enzyme assays, metal ion analyses, and, most recently, immunoassays. Although currently no role exists for the clinical laboratory in the early diagnosis of malignant melanoma, serial quantitative analyses of total or individual melanogens or of catecholamine metabolites in urine or plasma specimens may be of value in the management of patients with this disorder. Immunologically based methods for the diagnosis and management of malignant melanoma hold some promise for the future.

Melanin-related metabolites as markers of the skin pigmentary system

Three different groups of chemical intermediates are known to be formed during the synthesis of melanin in melanocytes: phenolic compounds, phenolic thio-conjugates, and indolic compounds. All these substances and their metabolites can be detected in urine. We measured the urinary excretion of 3,4-dihydroxyphenylalanine (dopa), 5-S-cysteinyldopa (5-S-CD), and 2 indolic compounds, namely 5-hydroxy-6-methoxyindole (5H6MI) and 5-hydroxy-6-methoxyindole-2-carboxylic acid (5H6MI2C) in urine samples of 4 groups of people with different contents of cutaneous melanin: Asian group, white group, and 2 groups of whites 1 with vitiligo and 1 with tyrosinase-negative oculocutaneous albinism. Dopa and 5-S-CD were determined with the method using high-performance liquid chromatography with an electrochemical detection. Indolic substances were measured by mass fragmentography with deuterium-labeled internal standards. Comparison of the melanin-related metabolites excreted in urine of people with different capacities for melanin biosynthesis indicates that, of all measured substances, 5H6MI2C is the best urinary marker of melanin formation in the skin pigmentary system.

Tomographic gallium-67 citrate scanning. Useful new surveillance for metastatic melanoma

Conventional gallium scans are not useful to evaluate patients with metastatic melanoma. We evaluated a new method of tomographic gallium imaging. One hundred fourteen tomographic scans were obtained in a prospective surveillance study of 67 patients over a 3-year period. Scans were evaluated and compared to findings of independent clinical evaluations. Sensitivity of gallium identification of tumor involving peripheral lymph nodes and soft tissues, abdomen, mediastinum, and osseous sites was 68% to 100%; overall sensitivity of this technique is 82% with specificity of 99% in 570 organ system assessments. Analysis of discordant findings when a site was clinically occult but gallium-positive showed gallium uptake to be true-positive in six of seven lymphatic sites, three of three lung and mediastinal sites, six of six abdominal sites, but in no brain or bone sites. Gallium lesions identified by computed tomographic scans proved to be false-positive at one lymphatic and one bone site, and false-negative at four otherwise clinically evident lymph node and soft tissue sites, seven pulmonary sites, and four brain sites. Gallium tomographic scanning provides a composite assessment of melanoma and may eliminate the need for other studies.

Evaluation of transsphenoidal hypophysectomy in the management of patients with advanced malignant melanoma

Transsphenoidal hypophysectomy was performed in 13 patients with advanced malignant melanoma. Although three minor responses were observed, there were no complete or partial responses. All three patients with bone pain had a decrease in discomfort lasting 1-2 months. All five patients with minor responses or stable disease had postoperative decreases in the excretion of the dihydroxyphenylalanine (DOPA) metabolite 3-O-methyldopamine; all but one patient with clinical progression had postoperative increases in excretion. Average survival of those whose postoperative excretion fell (143 +/- days; range, 60-217+) was significantly longer (P less than 0.004) than that of those whose postsurgical values rose (30 days; range, 15-58).

Determination of urinary 5-S-cysteinyldopa by high-performance liquid chromatography

A high-performance ion-pair liquid chromatographic method with electrochemical detection is described, which is suitable for routine determination of urinary 5-S-cysteinyldopa. The clean-up procedure includes a first purification step on the cation exchanger AG 50 W (H +). After desorption from the resin at moderately raised pH the catecholic amino acid is adsorbed on alumina at pH 8.6, washed and finally desorbed by elution with perchloric acid. By the combined clean-up procedures, easily oxidized compounds are eliminated, which otherwise cause a number of interfering peaks in the chromatography. The synthesis of 5-S-cysteinyl-L-3,4-dihydroxyphenyl [2,3-3H]alanine is described, and this tritium-labelled 5-S-cysteinyldopa is used to determine the recovery in the sample. The precision (C.V. = 5.7% at low and C.V. = 4.9% at high 5-S-cysteinyldopa concentration) and recovery (105.0 +/- 8.6%) were satisfactory. The mean urinary excretion was 0.34 +/- 0.13 (S.D.) mumol per 24 h (range 0.02-0.58 mumol per 24 h) in healthy subjects (n = 24) and in patients with melanoma metastates (n = 13) the excretion ranged from 0.9 to 4.8 mumol per 24 h.

The urinary melanogen cysteinyldopa in melanoma and in suntanning: Australian experience

Determination of urine cysteinyldopa excretion is the most sensitive chemical test for the detection of melanoma metastases and has been successfully applied during the Scandinavian winter, when sun irradiation is low. The value of this determination, under Australian conditions of greater sun irradiation, has been assessed by comparing the cysteinyldopa excretion of patients with that of normal subjects exposed to sunlight. Cysteinyldopa is an intermediate in the biosynthesis of the red-brown phaeomelanin. Of 20 patients without known secondary melanoma, the cysteinyldopa concentration of "spot" urines ranged from 0 to 190 (mean 48) microgram/ml; of six known to have local metastases, 0 to 80 (mean 19) microgram/ml; and of four known to have extensive metastases 80 to 1350 (mean 330) microgram/ml. The effect of sun irradiation alone was assessed in nine healthy subjects followed one to 11 weeks before and after recorded periods of sun exposure. The cysteinyldopa concentrations of 24-hour urines ranged from 40 to 3100 microgram/ml. Increases occurred three to 10 days following sun exposure and were greatest following multiple small exposures in an individual with "Celtic" complexion. It is concluded that measurement of cysteinyldopa concentration would be of value in the follow-up of melanoma patients in Australia only if patients could be persuaded to live under conditions free of all direct sun-irradiation.

Clinical evaluation of a method of quantitative determination of homovanillic acid for the estimation of degree of tumor dissemination process in melanoma of the skin

Homovanillic acid (HVA) was determined both in 45 patients with different forms of melanoma and those hospitalized on the suspicion of melanoma and in 15 healthy persons. Excretion rate of homovanillic acid within the normal limits was observed in patients with benign melanotic neoplasms of the skin (4.4 +/- 0.56 mg/24 hr) and in local forms of melanotic melanoma of the skin (4.5 +/- 0.24 mg/24 hr). In patients with metastases to regional nodes as well as in patients with locally disseminated forms of melanotic melanoma of the skin the concentration of homovanillic acid increased up to 11.1 +/- 0.93 mg/24 hr. Especially strong concentration of homovanillic acid was registered in patients with disseminated malanotic melanoma of the skin, and it made up 15.7 +/- 2.04 mg/24 hr. There was evident tendency to the elevation of HVA excretion level as generalization of the process which was taking place. The data obtained enable the authors to recommend the determination of HVA excretion as an additional diagnostic test as well for prognosis of melanoma development together with other clinicomorphological data.

Simple and sensitive test for the determination of phenolic compounds in urine and its application to melanoma

A simple procedure is outlined for the determination of phenolic compounds in urine. The method involves the diazotization of p-nitroaniline and subsequent coupling of the diazonium chloride with phenolic compounds. The diazo compound formed is determined by measuring the absorbance at 400 nm. The extinction coefficients for several compounds have been determined. Application of this method to determine the levels of phenolic compounds in urine in patients with melanoma showed that the assay may be of diagnostic value. The amounts of phenols in 24-hr urine samples from patients with melanoma, patients with various other diseases, and healthy individuals were determined. A statistical analysis of these results showed that the results for patients with melanoma were higher than those for healthy individuals and patients with other diseases at 1 percent probability level. A comparison of this test with three other methods (Thormählen test, ferric chloride test, and ferrocitrate test) for determination of melanogens showed that the diazo test is the most sensitive one for detecting melanoma.