A 45-year-old woman with HER2(-)/HER1(-)
breast cancer underwent
radical mastectomy, followed by radiation and
chemotherapy. However, her symptoms progressed rapidly owing to
meningitis carcinomatosa and she was fitted with a
urethral catheter. She also had difficulty in walking. However, immediately
after treatment with
lapatinib, her symptoms almost completely disappeared. The
catheter was removed and she no longer needed a wheelchair. Unfortunately,
after treatment was stopped, the bilateral upper limb skin
metastases reappeared, the
brain metastases relapsed, and she again experienced symptoms of
meningitis carcinomatosa.
Lapatinib was restarted, resulting in an immediate improvement in the symptoms and a reduction in the skin and
brain metastases. Immunohistochemical staining of the
lapatinib-sensitive metastatic skin
tumor showed it to be HER2(2+), FISH(-)/HER1(-). This result suggested that the
lapatinib-sensitive lesions in the brain and meninges were also HER2-positive. Carcinomatosa
meningitis has a very poor prognosis and no effective treatment has yet been developed. Here, we report the first case in which
lapatinib has been used to effectively treat
meningitis carcinomatosa in HER2(-)/HER1(-) relapsed
breast cancer.