Case report
A man aged 75 years was presented with a 1.5 months history of some scattered annular erythema and itching on his chest, abdomen and limbs (Fig. 1). The lesions, in different sizes, increased in number gradually and did not disappear during the period. Moreover, 4 bullous were observed on thigh of the patient (Fig. 1C, 1D). Nine months prior to presentation at our department, the patient had been diagnosed as esophageal cancer in other hospital and treated with the radical radiotherapy treatment. Currently, the treatment has been completed. It was noted that, there was no history of such conditions in family of the patient. Skin biopsy specimens were taken from the lesion of abdomen and the blister of thigh. Histopathologic examination in abdomen demonstrated accumulation of mononuclear cells in the epidermis, infiltration of eosinophils and lymphocytes in the dermal superficial layer (Fig. 2A). Immunohistochemical examination showed positive expressing of CD1a, S-100 and CD68 in epidermal cells and dermal cells aggregation, the expression of CD3, CD4, CD8, CD45RO as well as partly expression of CD5, CD7, CD20 and CD79a. The specimen was negative for CD207/Langerin (Fig. 3), CD56 and Ki-67. The histology of the blister reported the formation of old subepidermal blister, the slurry and eosinophils in the blister and infiltration of eosinophils and lymphocytes in the dermal superficial layer (Fig. 2B). Immunohistochemical study also showed that the histiocytes in epidermis and dermis co-expressed CD1a, S-100 and CD68 marker, but were negative for CD207/Langerin. They were also CD3, CD4, CD8, CD45RO, CD5, and CD7positive. Diagnosis of indeterminate cell histiocytosis was hence made based on these findings. Medical tests, such as routine laboratory tests, a bone marrow biopsy and computed tomographic (CT) scan, did not indicate any evidence of abnormality in other systems. He received symptomatic treatment with intravenous drip of Compound Glycyrrhizin, oral antihistamine (Medaclloratadine), topical Halometasone cream and humectant in the Department of Dermatology and was discharged due to a slight improvement in his condition a week later. However, 38 days later, the patient was presented at our dermatology clinic again for the blisters and bullous on the lower limbs (Fig. 4A). Histopathologic examination revealed the subepidermal blister and the infiltration of a large number of eosinophil in the blister and the dermis under the blister. Direct immunofluorescent (DIF) showed that IgG deposited in the basal membrane zone and IgM, IgA and C3 were negative (Fig. 4C). A diagnosis of bullous pemphigoid (BP) was hence made based on histopathologic examination and direct immunofluorescent. He was advised the treatment of Corticosteroid for BP and informed about possible side effects. The patient did not receive treatment for BP as advised. The patient had died of multiple organ failure about eight months from a telephone follow‐up.