In patients who have histories of extravasation with anticancer agents, recurrent inflammation at the site of extravasation sometimes occurs when the same drug is readministered at a different site. This reaction is referred to as "recall". We treated 6 patients who developed recall reactions despite having no obvious history of extravasation. One of these patients had a skin ulcer and required long-term treatment until it healed. Although the exact mechanism underlying the onset of the recall reaction is unclear, it may involve latent tissue damage caused by microleakage of pharmaceuticals.
We present two cases of hypokalaemia and QT prolongation in BRAF (V600) mutated metastatic cutaneous melanoma treated with vemurafenib.
Case 1: A 50-year-old Japanese man with chronic renal failure on hemodialysis presented with spinal bone metastasis 3 years after resection of primary shoulder melanoma. He began vemurafenib 960 mg bid. On day 36 after the administration, he developed hypokalemia and QT prolongation with palpitation. Case 2: A 56-year-old Japanese woman presented with multiple in-transit metastatsis in her left limb and with pleural metastasis 3 years after resection of her primary back lesion and adjuvant chemotherapy (DAV feron). She was treated with vemurafenib 960 mg bid until hypokalemia and QT prolongation developed. On day 35 after the administration, she developed hypokalemia and QT prolongation. In both patients, QT prolongation was grade 2 in CTCAE criteria. Discontinuation of vemurafenib improved these findings.
Although mechanism of hypokalemia in the patients treated with vemurafenib is still not fully understood, it could be a cause or potential exacerbating factors when it coexists with QT prolongation. Electrolyte abnormality should be closely monitored in vemurafenib-treated patients and routine electrocardiogram (ECG) is recommended.
A male teenager was found to have been infected with Zika virus after a visit to Brazil. This is the first Japanese case infected with Zika virus linked to the current outbreak in Latin America. At his first visit to the hospital, his fever had subsided and a widespread maculopapular rash had appeared. Zika virus (ZIKV) RNA was detected in urine using real-time RT-PCR. The rash disappeared after a few days, and the patient recovered without sequelae.