[Intralymphatic histiocytosis and cancer of the colon].

Intralymphatic histiocytosis is a condition with nonspecific clinical features but with characteristic histopathological and immunohistochemical findings. It presents as a poorly demarcated erythematous plaque or a lesion similar to livedo reticularis, usually located on the limbs. Histologically, dilated vessels containing mononuclear cells are observed in the reticular dermis. In the past, the majority of these cases were thought to be cases of reactive angioendotheliomatosis or intravascular lymphoma, but the development of more specific immunohistochemical markers showed that these were dilated lymph vessels containing histiocytes, and so were considered as a separate condition. We present the case of a man with a past history of left axillary lymphadenectomy for lymphatic tuberculosis, leukocytoclastic vasculitis, and cancer of the colon. The patient developed an erythematous plaque in the left pectoral region. Histology and immunohistochemical stains of the lesion revealed histiocytes within dilated lymph vessels in the reticular dermis, but no neoplastic cells. We present a new case of intralymphatic histiocytosis in a patient with autoimmune and neoplastic diseases.