Maguire Ciara A, Sharma Anup, Alarcon Lida, Ffolkes Lorrette, Kurzepa Malgorzata, Ostlere Lucy, Samarasinghe Venura, Singh Manuraj
Departments of *Dermatology, †Breast and Endocrine Surgery, and ‡Cellular Pathology, St George's University Hospital, London, United Kingdom.
Am J Dermatopathol. 2017 Aug;39(8):e110-e115. doi: 10.1097/DAD.0000000000000856.
Methylene blue is a chromophore dye known for its photosensitizing properties. It is also administered intravenously as a tracer in parathyroid surgery to identify abnormal glands. We describe 2 cases of acute methylene blue-induced phototoxicity in patients who underwent parathyroidectomy. Both patients developed an acute vesiculopustular inflammatory rash on the anterior neck corresponding to the site exposed intraoperatively to overhanging surgical lights. One of the patients also developed a bulla on her finger at the site of attachment of the oxygen probe. Biopsies were taken from both patients at different time points. The histological findings included destruction of sebaceous glands and deposition of diastase-periodic acid-Schiff-positive hyaline material around dermal blood vessels. These features are similar to those seen in skin treated with photodynamic therapy and systemic photosensitivity disorders such as the porphyrias. The wavelengths of light emitted by the surgical lights and oxygen probe overlap with the absorption spectrum of methylene blue. This resulted in excitation of the systemically administered methylene blue at exposed sites, with resultant local tissue damage and a phototoxic reaction.
亚甲蓝是一种以其光敏特性而闻名的发色团染料。它也在甲状旁腺手术中作为示踪剂静脉注射，以识别异常腺体。我们描述了2例在接受甲状旁腺切除术后发生急性亚甲蓝诱导的光毒性的患者。两名患者均在前颈部出现急性水疱脓疱性炎性皮疹，对应于术中暴露于悬垂手术灯的部位。其中一名患者在氧探头附着部位的手指上也出现了一个水疱。在不同时间点对两名患者进行了活检。组织学发现包括皮脂腺破坏和真皮血管周围淀粉酶-过碘酸-希夫阳性透明物质沉积。这些特征与光动力疗法治疗的皮肤以及系统性光敏性疾病（如卟啉病）中所见的特征相似。手术灯和氧探头发出的光波长与亚甲蓝的吸收光谱重叠。这导致全身给药的亚甲蓝在暴露部位被激发，从而导致局部组织损伤和光毒性反应。
