Palisaded encapsulated neuroma (PEN) : an often misdiagnosed neural tumor
Newman, M.D.; Milgraum, S.
Dermatology Online Journal 14(7): 12
2008
ISSN/ISBN: 1087-2108 PMID: 18718196 Document Number: 619828
We describe a unique case of a young man with concomitant Fragile X syndrome who presented with a dome-shaped pearly papule under the nose that had enlarged over 9 months. Histology demonstrated a smoothly contoured spindle cell neoplasm of the dermis with neuroid structures and foci of palisaded growth, consistent with a diagnosis of palisaded encapsulated neuroma (PEN). Palisaded encapsulated neuroma is a benign neural neoplasm of the skin or mucosa that displays histologic features of both a neurofibroma and a schwannoma. However, unlike these tumors, PEN lacks the implications for underlying systemic disease or malignancy. Palisaded encapsulated neuroma is a commonly underdiagnosed and misdiagnosed tumor that, once identified clinically and histologically, can be easily excised without recurrence.