Panniculitis Associated with MEK Inhibitor Therapy: An Uncommon Adverse Effect

Drug-induced neutrophilic lobular panniculitis secondary to BRAF and MEK inhibitor used for treatment of low-grade glioma and its management

An 8-year-old boy presented with his mother for evaluation of an erythematous rash 3 weeks after the start of dual BRAF-MEK inhibition with dabrafenib and trametinib for treatment of progression of low-grade glioma. Panniculitis has been reported as a rare adverse cutaneous event induced by BRAF inhibitors, MEK inhibitors, and the combined dual BRAF-MEK therapy. Based on the patient's history, clinical presentation, and histopathological findings, a diagnosis of drug-induced neutrophilic panniculitis was made. This case describes neutrophilic panniculitis as a potential cutaneous manifestation of dual BRAF-MEK inhibitor therapy and describes the management of such side effects. Neutrophilic panniculitis is a relatively rare manifestation, characterized by neutrophilic inflammation in the subcutaneous tissue. Additionally, this case serves as a reminder to consider the cutaneous side effects of such therapies, given that MEK and BRAF inhibitors are increasingly used to treat primary brain tumors in the pediatric population. Routine inspection and early management may improve patients' quality of life and enable continuation of anticancer therapy.

BRAF inhibitor-induced panniculitis in patients treated for stage IV metastatic melanoma: a case series

BRAF and MEK inhibitor combination therapy is the standard treatment for patients with BRAF V600E mutant metastatic melanoma. Neutrophilic panniculitis is a known rare complication of BRAF inhibitor therapy and can act as a potential mimic of melanoma metastases on ¹⁸F-FDG PET/CT. In this case series, we present three cases of BRAF inhibitor-induced panniculitis in patients being treated for BRAF-mutant metastatic melanoma and emphasize the use of ultrasound to differentiate between panniculitis lesions, which are typically ill-defined echogenic masses and subcutaneous soft tissue melanoma metastases, which present as hypoechoic vascular masses.

Dabrafenib-induced neutrophilic panniculitis in a child undergoing dual BRAF-MEK inhibitor therapy for glioblastoma multiforme

BRAF inhibitor-induced neutrophilic panniculitis is a rare event that is well-characterized in adults undergoing therapy for metastatic melanoma. To date, there are very few reports of this event in children undergoing BRAF inhibitor therapy for low-grade gliomas, all of which were seen with vemurafenib. We report a case of dabrafenib-induced neutrophilic panniculitis in a 9-year-old girl that manifested within several weeks of initiating dual BRAF-MEK inhibitor therapy for glioblastoma multiforme. This case highlights neutrophilic panniculitis as a side effect of dabrafenib in children and serves as a reminder to consider cutaneous side effects of BRAF inhibitors as they are increasingly used to treat children with primary brain tumors.

[Panniculitis during BRAF inhibitor and/or MEK inhibitor therapy: A new case report and literature review]

INTRODUCTION

BRAF inhibitors±MEK inhibitors can cause panniculitis. Since the initial case described in 2012 by Zimmer et al., some sixty further cases have been reported. Based on a clinical study and a recent and complete review of the literature, we set out in detail the characteristics of panniculitis occurring during BRAF and MEK inhibition therapy as well as the treatment thereof.

PATIENTS AND METHODS

A 25-year-old-patient followed for multi-metastatic melanoma and taking dabrafenib and trametinib consulted for the appearance, twenty-two days after the start of targeted therapy (TT), of panniculitis of the legs and forearms possibly induced by the TT after other causes had been ruled out. The TT had been continued following dose reduction and corticoid therapy for ten days, and complete resolution occurred after fifteen days.

RESULTS

Fifty-three cases of panniculitis during BRAF±MEK inhibition therapy were analysed. The condition occurred mainly with BRAF inhibitors alone (especially vemurafenib), but it was also described with three combinations of BRAF and MEK inhibitors, regardless of age (median: 45 years), with a M/F ratio of 0.51, and in 50 % of cases, it occurred within the first month (time to onset: between 1 and 480 days). Non-specific biopsy is useful to rule out differential diagnoses. Symptomatic anti-inflammatory treatment, whether systemic or topical, may be given. In the absence of signs of severity, the TT may be continued.

CONCLUSION

When panniculitis occurs during BRAF±MEK inhibitor therapy, the causal role of the TT must be considered after full etiological investigation. It is essential to determine whether a causal relationship exists in order to avoid unwarranted cessation of treatment.