Sequential occurrence of primary cutaneous indeterminate cell histiocytosis after oesophageal cancer and subsequent bullous pemphigoid: a case report.

Indeterminate cell histiocytosis is a rare proliferative histiocytic disease with an unknown aetiology, which shares immunophenotypic features of both Langerhans cells and macrophages. There is a relationship between indeterminate cell histiocytosis and cancer, while there are no reports about indeterminate cell histiocytosis and bullous pemphigoid. In this study, we reported the rare case of a patient with primary cutaneous indeterminate cell histiocytosis who had been diagnosed with oesophagal cancer and later developed bullous pemphigoid. The objective of this clinical case report is to analyse the association between solid tumours and indeterminate cell histiocytosis and focus on the coexistence of indeterminate cell histiocytosis and bullous pemphigoid in a patient with cancer. This study presented the case of a 75-year-old man who exhibited annular erythema lesions of variable size and papules scattered over his chest, abdomen, and limbs, along with four bullae on his thigh, persisting for 1.5 months. The patient also had a 9-month history of oesophageal cancer treated with radical radiotherapy. Histopathology and immunohistochemistry confirmed cutaneous indeterminate cell histiocytosis. Bullae and blisters developed on the lower limbs 38 days after treatment. A diagnosis of bullous pemphigoid was established based on clinical and histopathological features and results of direct immunofluorescence and enzyme-linked immunosorbent assay. Histopathological examination of the abdominal lesion revealed an accumulation of mononuclear cells in the dermis, with infiltration of eosinophils and lymphocytes in the superficial dermal layer. The histology of the blister on the thigh indicated the formation of an old subepidermal blister, with slurry and eosinophils present within the blister, and infiltration of eosinophils, lymphocytes, as well as histiocytoid cells in the superficial dermal layer. Immunohistochemical staining was positive for CD1a, S100, and CD68, and negative for CD207. Histopathological examination of blisters and bullae on the lower limbs revealed a subepidermal blister with infiltration of a large number of eosinophils within the blister and the dermis beneath it. Direct immunofluorescence showed that immunoglobulin Gs (IgGs) were linearly deposited in the basal membrane zone. The coexistence of oesophageal carcinoma, indeterminate cell histiocytosis, and bullous pemphigoid in a single patient represents a rare case that warrants consideration of possible underlying mechanisms.