Drug-induced eruptive melanocytic nevi

Cutaneous adverse drug reactions

Cutaneous adverse drug reactions (ADRs) represent a heterogeneous field including various clinical patterns without specific features suggesting drug causality. Maculopapular exanthema and urticaria are the most common types of cutaneous ADR. Serious cutaneous ADRs, which may cause permanent sequelae or have fatal outcome, may represent 2% of all cutaneous ADR and must be quickly identified to guide their management. These serious reactions include bullous manifestations (epidermal necrolysis i.e. Stevens-Johnson syndrome and toxic epidermal necrolysis), drug reaction with eosinophilia and systemic symptoms (DRESS) and acute generalized exanthematous pustulosis (AGEP). Some risk factors for developing cutaneous ADRs have been identified, including immunosuppression, autoimmunity or genetic variants. All drugs can cause cutaneous ADRs, the most commonly implicated being antibiotics (especially aminopenicillins and sulfonamides), anticonvulsants, allopurinol, antineoplastic drugs, non-steroidal anti-inflammatory drugs and iodinated contrast media. Pathophysiology is related to immediate or delayed "idiosyncratic" immunologic mechanisms, i.e., usually not related to dose, and pharmacologic/toxic mechanisms, commonly dose-dependent and/or time-dependent. If an immuno-allergic mechanism is suspected, allergological explorations (including epicutaneous patch testing and/or intradermal test) are often possible to clarify drug causality, however these have a variable sensitivity according to the drug and to the ADR type. No in vivo or in vitro test can consistently confirm the drug causality. To determine the origin of a rash, a logical approach based on clinical characteristics, chronologic factors and elimination of differential diagnosis (especially infectious etiologies) is required, completed with a literature search. Reporting to pharmacovigilance system is therefore essential both to analyze drug causality at individual level, and to contribute to knowledge of the drug at population level, especially for serious cutaneous ADRs or in cases involving newly marketed drugs.

Skin cancer in solid organ transplant recipients: still an open problem

In the last two decades, the optimization of organ preservation and surgical techniques, and the personalized immunosuppression have reduced the rate of acute rejections and early post-transplant complications. However, long-term graft survival rates have not improved over time, and evidence suggest a role of chronic calcineurin inhibitor toxicity in this failure. Solid organ transplant recipients may develop chronic dysfunction/damage and several comorbidities, including post-transplant malignancies. Skin cancers, mostly non-melanoma skin cancers (squamous cell carcinoma and basal cell carcinoma), are the most common malignancies in Caucasian solid organ transplant recipients. Several factors, together with immunosuppression, may contribute to the susceptibility for skin cancers which, although often treatable, could be associated with a much higher mortality rate than in the general population. The rapid identification and treatment (including reduction of immunosuppression and early surgical treatments) have an important role to avoid an aggressive behavior of these malignancies. Organ transplant recipients with a history of skin cancer should be followed closely for developing new and metastatic lesions. Additionally, patient education on the daily use of sun-protective measures and the recognition of the early signs (self-diagnosis) of coetaneous malignancies are useful preventive measures. Finally, clinicians should make themselves aware of the problem and build, in every clinical follow-up center, collaborative network involving transplant clinicians, dermatologists and surgeons who should work together to easily identify and rapidly treat these complications. In this review, we discuss the current literature regarding the epidemiology, risk factors, diagnosis, preventive strategies and treatments of skin cancer in organ transplantation.

Common genetic variants associated with melanoma risk or naevus count in patients with wildtype MC1R melanoma

BACKGROUND

Hypomorphic MC1R variants are the most prevalent genetic determinants of melanoma risk in the white population. However, the genetic background of patients with wildtype (WT) MC1R melanoma is poorly studied.

OBJECTIVES

To analyse the role of candidate common genetic variants on the melanoma risk and naevus count in Spanish patients with WT MC1R melanoma.

METHODS

We examined 753 individuals with WT MC1R from Spain (497 patients and 256 controls). We used OpenArray reverse-transcriptase polymerase chain reaction to genotype a panel of 221 common genetic variants involved in melanoma, naevogenesis, hormonal pathways and proinflammatory pathways. Genetic models were tested using multivariate logistic regression models. Nonparametric multifactor dimensionality reduction (MDR) was used to detect gene-gene interactions within each biological subgroup of variants.

RESULTS

We found that variant rs12913832 in the HERC2 gene, which is associated with blue eye colour, increased melanoma risk in individuals with WT MC1R [odds ratio (OR) 1·97, 95% confidence interval (CI) 1·48-2·63; adjusted P < 0·001; corrected P < 0·001]. We also observed a trend between the rs3798577 variant in the oestrogen receptor alpha gene (ESR1) and a lower naevus count, which was restricted to female patients with WT MC1R (OR 0·51, 95% CI 0·33-0·79; adjusted P = 0·002; corrected P = 0·11). This sex-dependent association was statistically significant in a larger cohort of patients with melanoma regardless of their MC1R status (n = 1497; OR 0·71, 95% CI 0·57-0·88; adjusted P = 0·002), reinforcing the hypothesis of an association between hormonal pathways and susceptibility to melanocytic proliferation. Last, the MDR analysis revealed four genetic combinations associated with melanoma risk or naevus count in patients with WT MC1R.

CONCLUSIONS

Our data suggest that epistatic interaction among common variants related to melanocyte biology or proinflammatory pathways might influence melanocytic proliferation in individuals with WT MC1R. What is already known about this topic? Genetic variants in the MC1R gene are the most prevalent melanoma genetic risk factor in the white population. Still, 20-40% of cases of melanoma occur in individuals with wildtype MC1R. Multiple genetic variants have a pleiotropic effect in melanoma and naevogenesis. Additional variants in unexplored pathways might also have a role in melanocytic proliferation in these patients. Epidemiological evidence suggests an association of melanocytic proliferation with hormonal pathways and proinflammatory pathways. What does this study add? Variant rs12913832 in the HERC2 gene, which is associated with blue eye colour, increases the melanoma risk in individuals with wildtype MC1R. Variant rs3798577 in the oestrogen receptor gene is associated with naevus count regardless of the MC1R status in female patients with melanoma. We report epistatic interactions among common genetic variants with a role in modulating the risk of melanoma or the number of naevi in individuals with wildtype MC1R. What is the translational message? We report a potential role of hormonal signalling pathways in melanocytic proliferation, providing a basis for better understanding of sex-based differences observed at the epidemiological level. We show that gene-gene interactions among common genetic variants might be responsible for an increased risk for melanoma development in individuals with a low-risk phenotype, such as darkly pigmented hair and skin.

Eruptive melanocytic nevi in a patient with amelanotic melanoma: a paraneoplastic phenomenon?

Eruptive melanocytic nevi (EMN) describes the sudden onset of cutaneous nevi over weeks or months. Such a clinical event is generally seen in young adult patients and may be related to several possible causes. We report here a case of EMN in an old male patient followed up for a thick amelanotic cutaneous melanoma. A few months after the eruption, multiple hepatic masses, diagnosed as melanoma metastasis, were detected. The presented case may suggest that EMN may be a paraneoplastic phenomenon of alert in patients being followed for melanoma or other malignancies.

Nevi, dysplastic nevi, and melanoma: Molecular and immune mechanisms involving the progression

Melanocytic nevi, dysplastic nevi, and melanoma are all derived from the pigment-producing cells, namely melanocytes. Concerning the clinical spectrum, cutaneous melanoma is the most aggressive skin cancer with a low survival rate, while nevi are the most common benign lesions in the general population, and dysplastic nevi place in between nevi and melanoma. Ultraviolet (UV) radiation is a well-recognized extrinsic risk factor for all three. BRAF^V600E is a well-recognized driver mutation that activates the RAS-BRAF-mitogen-activated protein kinase (MAPK) signaling pathway among 40%–60% of melanoma cases. Interestingly, BRAF^V600E mutation is detected even more in acquired nevi, approximately 80%. However, in nevi, several tumor suppressors such as p53 and phosphatase and tensin homolog (PTEN) are intact, and senescence factors, including p15^INK4b, p16^INK4a, p19, and senescence-associated acidic β-galactosidase, are expressed, leading to cell senescence and cell cycle arrest. Although loss of p53 function is rarely found in melanoma, decreased or loss of PTEN with an activated PI3k/Akt signaling pathway is common in nevi, which may abolish senescence status and allow further progression into dysplastic nevi or melanoma. At present, mouse models closely resembling human nevi are used for investigating these phenomena. Melanocortin 1 receptor deficiency, an intrinsic risk factor for melanomagenesis, is related to the production of procarcinogenic pheomelanin and the inhibition of PTEN function. Immune response escape via programmed cell death-1/programmed cell death ligand-1 interaction plays further roles in monitoring the spectrum. Here, we review the current literature on the molecular and immune mechanisms involving the transition from benign nevi to malignant melanoma.

Regulatory T Cells Play an Important Role in the Prevention of Murine Melanocytic Nevi and Melanomas

Melanocytic nevi are benign proliferations of pigment cells that can occasionally develop into melanomas. There is a significant correlation between increased nevus numbers and melanoma development. Our previous reports revealed that 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced dysplastic nevi in C3H/HeN mice, with a potential to transform into melanomas. To understand the immune mechanisms behind this transformation, we applied increasing DMBA doses followed by TPA to the skin of C3H/HeN mice. We observed that increased doses of DMBA correlated well with increased numbers of nevi. The increased DMBA dose induced diminished immune responses and promoted the expansion of regulatory T cells (Treg) that resulted in increased IL10 and reduced IFNγ levels. Mice with increased nevus numbers had loss of p16 expression. These mice had increased migration of melanocytic cells to lymph nodes (LN) and a greater percent of LNs produced immortalized melanocytic cell lines. DMBA-induced immunosuppression was lost in CD4-knockout (KO) mice. Lymphocytes in the CD4KO mice produced less IL10 than CD8KO mice. Furthermore, CD4KO mice had significantly reduced nevus numbers and size compared with wild-type and CD8KO mice. These results suggest that Tregs play a vital role in the incidence of nevi and their progression to melanoma.Prevention Relevance: There has been little progress in developing novel strategies for preventing premalignant dysplastic nevi from becoming melanomas. In this study in mice, regulatory-T cells enhanced progression of benign nevi to malignant melanomas; and by inhibiting their activity, melanomas could be retarded. The findings identify new possibilities for melanoma prevention in high risk individuals.

[Anti-TNF alpha-induced eruptive nevi: Three cases]

BACKGROUND

Eruptive melanocytic nevi (EMN) are a rare phenomenon characterized by simultaneous rapid onset of multiple nevi. The condition has been described in different contexts: immunosuppression, immunosuppressive drugs, targeted therapies, bullous diseases, and chemical melanocytic stimulation. We report 3 cases of EMN following anti-TNF alpha treatment.

PATIENTS AND METHODS

Case 1 - A 51-year-old female patient was receiving adalimumab for spondyloarthritis (the first treatment for this patient). A few months after the start of treatment, multiple nevi were noted on the 4 limbs, and in particular on the right palm. The patient confirmed the absence of these lesions before initiation of treatment. A diagnosis was made of adalimumab-induced EMN. Case 2 - A 49-year-old male patient was receiving etanercept for spondyloarthritis (the first biologic in this patient). Multiple small nevi developed on the trunk in the months after the start of treatment. The patient indicated that these lesions had appeared after the start of treatment. A diagnosis was made of etanercept-induced EMN. Case 3 - A 20-year-old woman with hidradenitis suppurativa was treated with infliximab. After 1.5 months, she reported the outbreak of various pigmented lesions 2-3mm in diameter on the trunk and one lesion on her right palm. The clinical diagnosis was EMN. After follow-up of 4 months to 5 years, no transformation to melanoma was noted in any of these 3 patients.

CONCLUSION

EMN remains a rare phenomenon in patients on anti-TNF alpha. These cases, associated with the description of a moderate increased risk of developing cutaneous carcinoma under anti-TNF alpha, underscore the need for dermatological follow-up and increased sun protection in patients receiving this treatment.