Hypopigmented macules secondary to imatinib for the treatment of chronic myeloid leukemia: a histopathologic and immunohistochemical study

Drug-Induced Pigmentation: A Review

Drug-induced pigmentation (DIP) is estimated to account for 20% of all cases of acquired hyperpigmentation. Over 50 agents have been implicated, including antibiotics, antimalarials, antiretrovirals, antipsychotics, prostaglandin analogs, heavy metals, and chemotherapeutic agents. The skin, mucosal surfaces, nails, and hair can all be affected, with the color, distribution, onset, and duration of pigmentation varying between offending agents. Both a thorough physical examination and medication history are necessary to determine the offending agent. In terms of mechanism, DIP occurs most frequently through the accumulation of melanin within the dermis but also by drug accumulation, pigment synthesis, and iron deposition. Photoprotection, including applying a broad-spectrum sunscreen, wearing photoprotective clothing, and seeking shade, plays an important role in the prevention of exacerbation of DIP. Multiple lasers, including the picosecond alexandrite, Q-switched Nd:YAG, Q-switched alexandrite, and Q-switched ruby lasers, have been successful in obtaining clearance of DIP. In this review, we examine the unique characteristics of each of the inciting agents in terms of incidence, clinical presentation, time to onset and resolution, and pathogenesis.

Therapeutic modulation of KIT ligand in melanocytic disorders with implications for mast cell diseases

KIT ligand and its associated receptor KIT serve as a master regulatory system for both melanocytes and mast cells controlling survival, migration, proliferation and activation. Blockade of this pathway results in cell depletion, while overactivation leads to mastocytosis or melanoma. Expression defects are associated with pigmentary and mast cell disorders. KIT ligand regulation is complex but efficient targeting of this system would be of significant benefit to those suffering from melanocytic or mast cell disorders. Herein, we review the known associations of this pathway with cutaneous diseases and the regulators of this system both in skin and in the more well-studied germ cell system. Exogenous agents modulating this pathway will also be presented. Ultimately, we will review potential therapeutic opportunities to help our patients with melanocytic and mast cell disease processes potentially including vitiligo, hair greying, melasma, urticaria, mastocytosis and melanoma.

Cutaneous side effects in a cohort of patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors: General description and further characterization, correlation with photoexposition and study of hypopigmentation as treatment's prognostic factor

Cutaneous adverse effects (AE) related to tyrosine-kinase inhibitor (TKI) drugs have been mainly described as case reports. We have characterized their appearance and correlation with patient's photoexposition habits and, further, with treatment response, in 61 patients with chronic myelogenous leukemia (CML) treated with TKI drugs. We have found hypopigmentation in 49.2% of the cases and a statistically significant association with interferon (IFN) intake. Eyelid edema's frequency was 45.4%. Mean photo-exposure was 1.95 h/day and only 8.3% of the patients used sunscreen daily. 44.3% of the patients reported a lighter skin color with the treatment and a statistically significant relationship with conjunctival hemorrhage was also found. Concordance between patients and dermatologist was moderate (kappa index 0.41). We found xerosis (21.3%), eczematous eruptions (21.3%), melasma (4.9%) and other isolated skin problems (ie, granulomatous panniculitis) in up to 16.4% of cases. Appearance of hypopigmented macules is associated to vascular conjunctival fragility and these patients need a slightly longer time to reach a complete molecular response, but without additional changes in survival or relapse frequency. We have stablished a specific dermatologic diagnosis in all the cases and we have not found the previously published as maculopapular rashes. Hypopigmentation, the more frequent AE, was not perceived as a relevant side effect. Photosensitivity, in our cases, was not reported, although imatinib-treated patients avoided sun-exposure. In addition, we identified some nonpreviously described dermatologic conditions in patients taking TKI drugs, like granulomatous panniculitis tufted folliculitis or oral spindle cell lipoma.

Pigmentation Disorders in the Elderly

Aging skin is subject to morphological change due to both intrinsic (skin tone, genetics, endogenous hormones) and extrinsic (chronic sun exposure, medications, exogenous pigments) factors. The broad spectrum of transformation includes both hypo- and hyperpigmentation. Although cutaneous pigmentary disorders are common in younger individuals, certain disorders are more prevalent in the geriatric population. This article reviews the epidemiology, pathophysiology, clinical appearance, treatment, and prognosis of pigmentary lesions that are predominant in the elderly.

An Update on Drug-Induced Pigmentation

Drug-induced pigmentation accounts for up to 20% of all cases of acquired pigmentation. A thorough review of medical history and previous and ongoing medications as well as a complete skin examination can guide diagnosis. Implicated agents include alkylating/cytotoxic agents, analgesics, antiarrhythmics, anticoagulants, antiepileptics, antimalarials, antimicrobials, antiretrovirals, metals, prostaglandin analogs, and psychotropic agents, among others. Confirming true drug associations can be challenging, especially in the setting of delayed onset of pigmentation and coexisting polypharmacy.

European LeukemiaNet recommendations for the management and avoidance of adverse events of treatment in chronic myeloid leukaemia

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.

Clinical and histopathologic analysis of 46 cases of cutaneous adverse reactions to imatinib

BACKGROUND

Although many cases of cutaneous adverse reactions to imatinib have been reported, their clinical and histopathologic characteristics are not well documented.

OBJECTIVES

The present study investigated clinical and histopathologic characteristics of cutaneous adverse reactions to imatinib.

METHODS

This retrospective study referred to 46 patients who experienced cutaneous adverse reactions to imatinib. Clinical data including age, sex, skin lesion morphology, underlying disorders, and imatinib treatment parameters (duration of imatinib medication, initial dose, and treatment modifications at the time of the study) were collected. Histopathologic data were available for all patients.

RESULTS

Cutaneous adverse reactions to imatinib developed at 1-24 weeks (median onset: 8 weeks) after imatinib administration. The severity of the reaction was categorized as grade 1 in 22%, grade 2 in 41%, and grade 3 in 37% of patients. Onset was earlier in high-severity reactions than in low-severity reactions. The severity of the reaction was dependent on imatinib dose. Grade 3 reactions were noted in nine of 16 (56%) patients administered "high-dose" (600 mg/d) imatinib. Spongiosis (78% of patients) and papillary dermal edema (83% of patients) were common histopathologic findings in the epidermis and dermis, respectively. Lymphohistiocytes were more predominant than eosinophils in dermal inflammatory infiltration. Histopathologic findings did not differ according to dose of imatinib or severity of the reaction.

CONCLUSIONS

Although the clinical features of cutaneous adverse reactions to imatinib depend on imatinib dose and the severity of the reaction, histopathologic findings are not associated with these clinical variables.