Hypercalcemia in a patient with malignant melanoma arising in congenital giant pigmented nevus. A case of increased serum level of parathyroid hormone-related protein

Serum calcium, albumin and tumor stage in cutaneous malignant melanoma

AIM

Assess the relationship of serum calcium and serum albumin to tumor stage and other clinical characteristics in patients with cutaneous malignant melanoma (MM).

PATIENTS & METHODS

A cross-sectional study to evaluate serum calcium as a marker of disease progression (n = 644) in MM.

RESULTS

Serum albumin was significantly lower among men (p < 0.01) and among patients with stage 4 disease (p < 0.05). In a multivariable regression model adjusted for age, gender and site, albumin-corrected calcium was positively associated with disease stage (odds ratio: 1.46; 95% CI: 1.02-2.07; p = 0.04). The odds of higher stage increased 60% for each 1.0 mg/dl increase in albumin-corrected calcium.

CONCLUSION

Higher albumin-corrected serum calcium may be a marker of disease progression in MM.

Parathyroid Hormone-Related Peptide-Linked Hypercalcemia in a Melanoma Patient Treated With Ipilimumab: Hormone Source and Clinical and Metabolic Correlates

A patient diagnosed with metastatic melanoma developed the paraneoplastic syndrome of humoral hypercalcemia of malignancy and cachexia after receiving ipilumumab. The cause of the hypercalcemia was thought to be secondary to parathyroid hormone-related peptide (PTHrP) as plasma levels were found to be elevated. The patient underwent two tumor biopsies: at diagnosis (when calcium levels were normal) and upon development of hypercalcemia and cachexia. PTHrP expression was higher in melanoma cells when hypercalcemia had occurred than prior to its onset. Metabolic characterization of melanoma cells revealed that, with development of hypercalcemia, there was high expression of monocarboxylate transporter 1 (MCT1), which is the main importer of lactate and ketone bodies into cells. MCT1 is associated with high mitochondrial metabolism. Beta-galactosidase (β-GAL), a marker of senescence, had reduced expression in melanoma cells upon development of hypercalcemia compared to pre-hypercalcemia. In conclusion, PTHrP expression in melanoma is associated with cachexia, increased cancer cell lactate and ketone body import, high mitochondrial metabolism, and reduced senescence. Further studies are required to determine if PTHrP regulates cachexia, lactate and ketone body import, mitochondrial metabolism, and senescence in cancer cells.

Mechanisms and treatment of hypercalcemia of malignancy

PURPOSE OF REVIEW

Hypercalcemia of malignancy is a common paraneoplastic syndrome and a frequent complication of advanced breast and lung cancer, and multiple myeloma. The development of this malignancy complication often purports a poor prognosis. Thorough evaluation to establish the cause of hypercalcemia is essential because some patients may actually have undiagnosed primary hyperparathyroidism.

RECENT FINDINGS

Production of humoral factors by the primary tumor, collectively known as humoral hypercalcemia of malignancy (HHM), is the mechanism responsible for 80% of cases. The vast majority of HHM is caused by tumor-produced parathyroid hormone-related protein followed by infrequent tumor production of 1,25-dihydroxyvitamin D and parathyroid hormone. The remaining 20% of cases are caused by bone metastasis with consequent bone osteolysis and release of skeletal calcium. Key therapies are saline hydration to promote calciuresis and bisphosphonates to reduce pathologic osteoclastic bone resorption. Calcitonin and glucocorticoids, especially in 1,25-dihydroxyvitamin D-mediated HHM, also have calcium-lowering effects.

SUMMARY

Recent discoveries on mechanisms of malignancy-associated hypercalcemia highlight the critical role of the osteoclast. Bisphosphonates and other novel therapies being evaluated in clinical trial target this bone-resorbing cell type and provide effective and durable serum calcium reduction.

Congenital melanocytic nevi

The relative risk for melanoma arising within a congenital nevus is related to the size of the lesion. The timing of and clinical presentation of development of melanoma is also related to the size of the lesion. Medical decisions are individualized taking into account the perceived risk of malignancy, psychosocial impact, and anticipated treatment outcome. In this article, the common features of congenital nevi are discussed as well as the potential individual variations and their impact on treatment recommendations.

A retrospective cohort study of Southeast Asian patients with large congenital melanocytic nevi and the risk of melanoma development

BACKGROUND

The lifetime risk of developing melanoma in Caucasian patients with large congenital melanocytic nevi (LCMN) is estimated to be between 4.5% and 10%. Cohort studies of LCMN and the risk of melanoma development in an Asian population are not available.

OBJECTIVE

We sought to determine the risk of melanoma development in a retrospective cohort of patients presenting with LCMN to a dermatology tertiary referral center in Singapore from January 1989 to December 2004.

METHODS

Patients with congenital melanocytic nevi (CMN) that covered at least 5% of the body surface area were included in the study. Data were obtained from electronic records and photographic documentation. A search for malignancy was done using the National Cancer Registry database.

RESULTS

In all, 39 patients (23 male and 16 female) met the study criteria of LCMN; 15 of 39 patients also met the criteria of having a giant CMN (ie, a CMN that is predicted to be at least 20-cm diameter in adulthood). There were 29 Chinese, 6 Malay, 1 Indian, and 3 Caucasian patients. Their ages ranged from 23 months to 60 years (mean 18.8 years). They presented at a mean age of 26 months and were followed up for an average of 16.9 years. The size of the LCMN ranged from 5% to 40% of body surface area, with a mean of 12.2%. The most common sites were the back (54%), lower limb (28%), and abdomen (26%). Satellite lesions were present in 22 patients. Magnetic resonance imaging of the head or thoracolumbar spine was performed in 7 patients with LCMN on the scalp/face or back, respectively; all produced normal findings. Only one patient was treated: he had carbon-dioxide laser ablation and Q-switched neodymium:yttrium-aluminum-garnet laser treatment of a small part of his LCMN. Skin biopsies were done in 5 patients who had developed nodules; histology showed no evidence of malignancy. No patients had developed any form of malignancy.

LIMITATIONS

The addition of 3 adult patients born before the start of the cancer registry may have led to survivor bias. The small sample size did not allow a precise estimate of the risk of melanoma development in our study population.

CONCLUSION

The risk of melanoma development in LCMN within a predominantly Southeast Asian cohort appears to be very low. Prophylactic complete excision of LCMN is ideal, but seldom achievable. Hence, patient education, regular melanoma surveillance, and biopsy of suspicious lesions are very important.

Widespread expression of parathyroid hormone-related peptide in melanocytic cells

BACKGROUND

Parathyroid hormone-related peptide (PTH-rP) was associated with the syndrome of hypercalcaemia of malignancy. An increased serum level of PTH-rP could occur in patients with advanced melanoma.

OBJECTIVES

We examined PTH-rP expression in cultured melanocytic cell lines and in lesions of melanocytic origin for associations with clinicopathological variables of disease progression. We measured the supernatant and cell lysate level of PTH-rP in cultured melanoma cells to clarify whether melanoma cells secrete PTH-rP.

METHODS

PTH-rP expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) in cultured melanocytic cell lines and by immunoperoxidase staining in 18 melanocytic naevi, 40 primary melanoma and 19 metastatic melanoma lesions. The supernatant level of PTH-rP was measured with an immunoradiometric assay.

RESULTS

RT-PCR products of PTH-rP mRNA were detected in six of eight melanoma cell lines; however, neither naevus cells nor melanocytes showed positive products. On the other hand, immunohistochemical analysis showed that PTH-rP was widely expressed both in benign and malignant melanocytic lesions. In addition, PTH-rP expression was not associated with any clinicopathological variables. Cell lysate but not the supernatant of melanoma cells showed high PTH-rP levels.

CONCLUSIONS

These results suggest that PTH-rP was widely expressed in melanocytic cells; however, the cells did not secrete PTH-rP.

Hypercalcemia and high parathyroid hormone-related protein concentration associated with malignant melanoma in a dog

A 12-year-old Cocker Spaniel with an oral malignant melanoma was evaluated for progressive lethargy and anorexia. No metastases were identified during antemortem evaluation, but severe hypercalcemia was evident. Antemortem diagnostic testing failed to identify a cause for the hypercalcemia. No neoplasms other than the melanoma were identified on postmortem examination. Serum parathyroid hormone-related protein concentration was markedly high, and the melanoma had moderate to marked immunostaining for this protein. Paraneoplastic syndromes are rare in dogs with malignant melanoma.

Expression and regulation of parathyroid hormone-related peptide in normal and malignant melanocytes

We examined parathyroid hormone-related peptide (PTHrP) production and regulation in both normal human melanocytes and in a human amelanotic melanoma cell line (A375). Northern blot and immunocytochemical analysis demonstrated that both cultured A375 cells and normal human melanocytes express PTHrP, but A375 cells expressed much higher levels of the peptide. PTHrP secretory rate increased at least 10-fold after treatment with 10% fetal bovine serum (100.2 +/- 2.8 pmol/10(6) cells vs. basal <15 pmol/10(6) cells) in proliferating A375 cells but only twofold in confluent cells. Treatment of A375 cells with increasing concentrations of 1, 25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] or its low-calcemic analog EB-1089 revealed that EB-1089 was 10-fold more potent than 1, 25-(OH)(2)D(3) on inhibition of both cell proliferation and PTHrP expression. Furthermore, inoculation of A375 cells into the mammary fat pad of female severe combined immunodeficiency mice resulted in the development of hypercalcemia and elevated concentrations of plasma immunoreactive PTHrP in the absence of detectable skeletal metastases. Our study, therefore, demonstrates a stepwise increase in PTHrP expression when cells progress from normal to malignant phenotype and suggests that EB-1089 should be further evaluated as a therapeutic agent in human melanoma.