Vemurafenib-induced histiocytoid neutrophilic panniculitis simulating myeloid leukaemia cutis

Connective tissue panniculitis and vitiligo in a patient with stage IV melanoma achieving complete response to dabrafenib and trametinib combination therapy

The combination of BRAF and MEK inhibitors, such as dabrafenib and trametinib, respectively, is an established treatment option for patients with advanced BRAFV600-mutated melanoma. With the wide adoption of these therapies, a range of cutaneous adverse effects has been reported. We describe the case of a 47-year-old woman with BRAFV600E-mutated stage IV melanoma treated with dabrafenib and trametinib for 30 months who presented to our attention for painful skin lesions that had been present on her limbs since the start of targeted therapy. We also observed vitiligo-like lesions on the extensor surface of both legs. Despite achieving a complete oncological response, the patient had to discontinue the treatment because of persisting fever, nausea and painful skin nodules that significantly impaired her quality of life. The recognition of cutaneous signs of efficacy of such drugs for advanced melanoma is of primary importance in order to identify patients with potential long-term clinical benefits.

Neutrophilic Infiltrates in Panniculitis: Comprehensive Review and Diagnostic Algorithm Proposal

Neutrophilic infiltrates in panniculitis can be seen in different clinical-pathological entities. There are a "mostly neutrophilic inflammatory infiltrate" in some entities classically defined as neutrophilic panniculitis and already included in algorithms, such as enzymatic panniculitis, infective and factitial ones, erythema induratum, or subcutaneous Sweet syndrome, but there are also other panniculitis where neutrophils are frequently observed such as panniculitis associated with inflammatory bowel disease or rheumatoid arthritis, or drug-induced panniculitis associated with BRAF inhibitors, and finally, some panniculitis are better classified in other panniculitides groups but may present with neutrophil-rich variants, such as the neutrophil-rich subcutaneous fat necrosis of the newborn. We review the main clinical and histopathological features of most of these panniculitides and construct a diagnostic algorithm including these diseases.

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.