What is an epithelial sheath neuroma?
Epithelial sheath neuroma is a rare benign cutaneous tumour composed of dermal nerve fibres surrounded by squamous epithelium [1,2].
Who gets epithelial sheath neuroma?
Epithelial sheath neuroma has so far only been reported in 13 people; all have been older than 40 years of age. It has been reported most commonly in females .
What causes an epithelial sheath neuroma?
The pathogenesis of epithelial sheath neuroma has not been determined, however several possible mechanisms have been suggested.
- A reactive hyperplasia of peripheral nerves and epithelium in response to an external stimulus or to entrapment of epithelium within the perineurium (a sheath of connective tissue) .
- Squamous metaplasia of the perineurium of enlarged nerve bundles as a reaction to localised inflammation .
- Neural crest remnants from embryonal development that differentiated into neural and squamous epithelial elements .
- Interleukin 6-mediated hyperplasia in response to localised inflammation or minor trauma at the site of a previous skin biopsy .
What are the clinical features of epithelial sheath neuroma?
Epithelial sheath neuroma presents as a persistent erythematous papule or nodule located on the upper or mid-back. Some patients report tenderness, pruritus, or paraesthesia when the lesion is palpated .
How is epithelial sheath neuroma diagnosed?
Epithelial sheath neuroma is diagnosed by histopathological examination of a skin biopsy. It is characterised by multiple enlarged peripheral nerve fibres that are sheathed by mature squamous epithelium. Epithelial sheath neuroma is sometimes surrounded by myxoid (mucus-like) stroma and a lymphocytic infiltrate.
Histology of epithelial sheath neuroma
What is the differential diagnosis for epithelial sheath neuroma?
The clinical differential diagnosis for epithelial sheath neuroma may include:
- Squamous cell carcinoma
- Basal cell carcinoma
- Inflamed cyst
- Inflamed or irritated melanocytic naevus.
The histological differential diagnosis for epithelial sheath neuroma includes reactive neuroepithelial aggregates, perineural invasion of a well-differentiated cutaneous carcinoma, or re-excision perineural invasion [7,8].
What is the treatment and outcome of epithelial sheath neuroma?
Epithelial sheath neuroma is benign.
The treatment of choice is excision, with no reports of recurrence after excision to date .