Oral plexiform schwannoma with unusual epithelial induction.
Rare epithelial structures in benign nerve sheath tumors are almost always glandular in appearance. We describe a case of intraoral plexiform schwannoma with concurrent squamous epithelial hyperplasia. The lesion occurred as a pigmented nodule on the gingiva of a 35-year-old woman with no systemic involvement. Histologically, unencapsulated, plexiform fascicular proliferations of schwann cells could be traced from the submucosa to the lamina propria, finally making direct contact with heavily pigmented, elongated rete ridges of the overlying epithelium. Also noted was a schwannian network centered on clustered odontogenic epithelial rests of mature squamous-type, the number and size of which had markedly increased. Impressive immunoprofiles of periepithelial neural microfascicles included the complete absence of axon and perineurium and the unexpected presence of endoneurial fibroblasts. The repertoire of epithelial changes was in a confined area with no extension beyond, supporting hyperplasia induction by an underlying/surrounding schwannoma.
Department of Diagnostic Pathology, Tsurumi University School of Dental Medicine, Yokohama, Japan.|Department of Pathology, Tsurumi University School of Dental Medicine, Yokohama, Japan.|Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
Fumio
F
Ide
Department of Endodontics and Clinical Cariology, Tokyo Dental College, Tokyo, Japan.
Takashi
T
Muramatsu
Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
Kentaro
K
Kikuchi
Department of Pathology, Tsurumi University School of Dental Medicine, Yokohama, Japan.
Ichiro
I
Saito
Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
Kaoru
K
Kusama
epithelial induction; neuroepithelial hamartoma; oral cavity; plexiform schwannoma