Lipoblast-like signet-ring cells in neurofibroma: a potential diagnostic pitfall of malignancy

Benign peripheral nerve sheath tumours, including neurofibroma,may occasionally contain a heterologous mature fatty component.Additional lipoblast-like cells can be occasionally identifiedamong mature adipocytes. We report the first case of a plexiformneurofibroma from a N F1 patient containing exclusivelylipoblast-like cells exhibiting morphological and immunohistochemicalfeatures identical to univaculoted lipoblasts typicallyseen in myxoid liposarcoma. Awareness of the possibility that anotherwise typical neurofibroma may contain lipoblast-like cells iscrucial for the pathologist to avoid a misdiagnosis of malignancy.Differential diagnostic problems and histogenetic considerationsare provided.