Type of publication:
Ieremia E., *Mudaliar V., *Kelly S., Grech B., Rodriguez P., Martin B., Calonje E.
British Journal of Dermatology, July 2014, vol./is. 171/(90), 0007-0963 (July 2014)
Dermal hyperneury is defined as the presence of increased and hypertrophic myelinated and nonmyelinated nerve fibres in the dermis. Cutaneous nerve hyperplasia is rare and can be seen in lesional skin in multifocal or localized forms. When multifocal, it can be present in a pure cutaneous or mucocutaneous form or it may have syndromic associations. It is fascinating that it is present in the normal skin of patients with multiple endocrine neoplasia type 2b (MEN2b) and Cowden syndrome, but also in the lesional skin of those patients, as well as in neurofibromatosis (type 2), attenuated forms of MEN2b and in medullary thyroid carcinoma with macular amyloidosis. Localized, it may be encountered in areas of trauma, nodular prurigo, notalgia paraesthetica, neurocristic hamartoma and rarely in cases of chronic rubbing/scratching (Schaffer JV, Kamino H, Witkiewitcz A et al. Mucocutaneous neuromas. An underrecognised manifestation of PTEN hamartoma- tumor syndrome. Arch Dermatol 2006; 142: 625-32; Winkelmann RK, Carney JA. Cutaneous neuropathology in multiple endocrine neoplasia, type 2b. J Invest Dermatol 1982; 79: 307-12). We present six cases spanning through the spectrum of conditions described. We describe four patients with multiple cutaneous papules, variably symptomatic. Extensive investigations did not reveal any syndromic associations. Furthermore, we include two localized forms: one case of notalgia paraesthetica and one case of trauma. It is interesting to note that PTEN and RET mutations seen in Cowden and MEN2b syndromes, respectively, are implicated in common pathways of the growth and development of neural-crestderived and nerve tissue. We would like to propose dermal hyperneury as a distinct rare entity specifically in those cases presenting with multiple lesions confined to the skin and no syndromic stigmata, and therefore, no associated risk of malignancy.