Progressive Langerhans’ cell histiocytosis in a puppy

Abstract

A 8‐month‐old, female miniature Dachshund dog was presented for the complaint of pruritic, generalized, multiple nodules and plaques. Two months previously, a nodule on the left pinna was excised and diagnosed as a cutaneous histiocytoma. One month post‐excision, a nodule reappeared at the same site and, shortly thereafter, additional nodules developed. Histopathological examination revealed a diffuse proliferation of histiocytic cells, which reacted strongly to antibodies for vimentin and lysozyme. Immunophenotypic analysis showed that most of the cells expressed CD1a, CD1c, CD11c, CD18, CD45 and MHC class II markers. Electron microscopic examination revealed cytoplasmic filopodia and paracrystalline structures. These findings indicated that the cells originated from Langerhans’ cell. The disease progressed despite glucocorticoid therapy and griseofulvin was administered as an immunomodulating drug. All lesions resolved completely after 7 weeks of griseofulvin treatment. The dog, however, died three months later after discontinuation of griseofulvin therapy and a necropsy was not performed. It is considered that the present canine dermatosis corresponds with a severe form of Langerhans’ cell histiocytosis in humans rather than canine cutaneous histiocytoma.