A Case of Late-Onset Neurofibromatosis Speculated as Type 7: Brief Overview

Neurofibromatosis (NF) is one of the commonest hamartoneoplastic syndromes and is an autosomal
dominant neurocutaneous syndromes. NF type 1 and NF type 2 are the main forms of NF. NF type 3
to type 8 are very rare but accurate their incidences are not known. NF type 7 occurs rarely in late
adulthood (from age 30 onward) and is characterized by schwannoma or neurofibroma, skin freckling,
but no café-au-lait spot.
Recently, a first Japanese case of late onset NF speculated as type 7 was reported. A 65-year-old
woman developed freckling on her skin from axillary to inguinal regions at age 40. At age 55 and 63,
she had respectively, a subcutaneous tumor from her right buttock and a left acoustic tumor removed,
in both cases, histopathological analyses diagnosed a schwannoma. At age 65, she was admitted to
the hospital for a detailed examination of an abdominal mass previously detected by MRI. The patient
had no family history of schwannoma, nor presented café-au-lait skin spots. The abdominal mass was
diagnosed as a retroperitoneal tumor by enhanced-CT-scan, MRI and FDG-PET/CT. Needle biopsy
examinations confirmed a schwannoma diagnosis. Thus, it is considered she is a very rare case of
late-onset neurofibromatosis speculated as type 7.