Nodular solar elastoma on the face

previously, if the tumor tests positive for human epidermal growth receptor 2 (HER2), the humanized monoclonal anti-HER2 antibody trastuzumab is effective. Furthermore, a trastuzumab-biosimilar (trastuzumab-BS) has shown equivalent effects against breast cancer, and its cost is lower. In this report, we describe a case of metastatic EMPD treated with a trastuzumab-BS as second-line chemotherapy. The patient was a 69-year-old man who had been treated for right inguinal and perianal erythematous lesions. After 2 years, his lesions expanded (Fig. 1a) and he developed abdominal pain. Computed tomography revealed multiple lymphadenopathy in the right inguinal and periaortic regions. Skin biopsy was then performed; EMPD was diagnosed (Fig. 1b). Serum cytokeratin (CK)19 fragment (CYFRA 21-1) level was 4.4 ng/mL. Immunohistochemistry revealed that he was CK7positive, CK20-negative and HER2-equivocal (2+) (Fig. 1c). Because of the cost, he refused to undergo additional HER2 analysis. Therefore, we administrated monthly S-1 (60 mg/m, days 1–14) and docetaxel (35 mg/m, day 1) as first-line chemotherapy. After three cycles, all metastatic lymph nodes regressed quickly; this was categorized as partial response (Response Evaluation Criteria in Solid Tumors version 1.1). However, after six cycles, a 20-mm diameter tumor was detected in the cutaneous lesion (Fig. 1d). We dissected the tumor, but after a month, the lymph nodes re-progressed and serum CYFRA level increased from 2.3 to 3.5 ng/mL. The patient agreed to undergo fluorescence in situ hybridization, and HER2 amplification was proved (Fig. 1e). We discontinued first-line therapy and initiated second-line trastuzumab-BS therapy. The trastuzumab-BS was administrated biweekly at a loading dose of 4 mg/kg and maintenance dose of 2 mg/kg. After four cycles, lymph node progression was suppressed and CYFRA level was reduced to 2.1 ng/mL. Six months after the switch, lymph node size was indicative of stable disease (Fig. 1f), and no significant adverse events were seen. In this case, second-line trastuzumab-BS monotherapy was initiated. The efficacy of a combination with docetaxel or paclitaxel has been previously reported; however, we considered that the tumor in this case might have developed taxane resistance. Moreover, considering the cost and risk, we selected monotherapy and extended the interval between the weekly regimens. The median survival time of patients with progressed EMPD is 14.5 months, and of patients with progressed EMPD treated with docetaxel 16.6 months. However, our patient’s survival time was over 20 months from the first chemotherapy; this treatment may help improve the prognosis. There are few reports about effective second-line chemotherapy for EMPD; to the best of our knowledge, this is the first case where trastuzumab or trastuzumab-BS monotherapy was effective as second-line treatment. To reduce patient burden by avoiding multiple therapies, second-line trastuzumab-BS monotherapy is a good option.