Our Dermatol Online Our Dermatol Online 2081-9390 Our Dermatology Online Poland OURD-7-485 10.7241/ourd.20164.133 Letter to the Editor Neurothekoma of the scalp Hadj Olfa El Amine El 1 Bouhajja Leila 1 Goucha Aida 1 Hassouna Jameleddine Ben 2 Rekik Wafa 1 May Ahmed El 1 Gamoudi Amor 1 Department of Pathology, Carcinological Institute Salah Azaiez, Tunis, Tunisia Department of Carcinological Surgery, Carcinological Institute Salah Azaiez, Tunis, Tunisia Corresponding author: Dr. Olfa El Amine El Hadj, E-mail: olfaelamine@yahoo.fr 2016 7 4 485 486 06032016 24042016 Copyright: © Our Dermatol Online 4 2016

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 <p>Sir,</p> <p>We report a 30 year-old woman with a history of lumpectomy for a benign breast tumor, presented with a 10-year history of an exophytic lesion of the scalp. The physical examination revealed a giant mass on the scalp, which was immobile, tender and exhibited distinct borders. A total excision of the lesion was performed. Grossly, the tumor was nodular, exophytic, and measured 19 cm of diameter. Histological examination showed a tumor consisting of spindle to epitheloid cells forming micro nodules in a concentric whorled shape pattern (<xref ref-type="fig" rid="F1">Fig 1</xref>) embedded in abundant myxoïd stroma (<xref ref-type="fig" rid="F2">Fig. 2</xref>). These features confirmed the diagnosis of a neurothekoma. At 3 years of follow-up, the patient was asymptomatic and there was no recurrence.</p> <fig id="F1"> <label>Figure 1</label> <caption> <p>Subcutaneous layer containing whorls of regular fusiform cells.</p> </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-7-485-g001.tif"/> </fig> <fig id="F2"> <label>Figure 2</label> <caption> <p>Epitheloid and fusiform cells embedded into a myoid stroma.</p> </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-7-485-g002.tif"/> </fig> <p>The patient’s informed consent was obtained.</p> <p>Prior to the study, patient gave written consent to the examination and biopsy after having been informed about the procedure.</p> <p>Neurothekoma (NT) is an uncommon and benign dermal tumor, originating from the sheath of peripheral nerves. It is mainly located on the face, neck, arms and shoulders of young adults, and is more frequent in females [<xref ref-type="bibr" rid="ref1">1</xref>,<xref ref-type="bibr" rid="ref2">2</xref>].</p> <p>Clinically, it manifests as an asymptomatic, pink-erythematous, dome-shaped, solitary papule or nodule, with a slow growth rate [<xref ref-type="bibr" rid="ref2">2</xref>]. The clinical differential diagnosis of NT includes epidermal cyst, dermatofibroma, adnexal tumor (e.g. pilomatricoma), Fibrohistiocytic tumor, Basal cell carcinoma, hemangioma, amelanotic melanoma and cutaneous metastasis [<xref ref-type="bibr" rid="ref2">2</xref>].</p> <p>Histological examination shows the presence of spindle and epithelioid cells with abundant granular-eosinophilic cytoplasm and a tendency to be grouped in whorled nodules spared by collagen bundles in the dermis and subcutaneous area. There may be sclerotic collagen and osteoclast-like cells [<xref ref-type="bibr" rid="ref3">3</xref>]. Furthermore, this tumor is subclassified histopathologically into 3 groups: myxoid, mixed, and cellular type depending on the amount of myxoid matrix [<xref ref-type="bibr" rid="ref4">4</xref>]. Immunohistochemically, the S100 protein is useful to differenciate the myxoid type from the cellular type. The tumor cells of the cellular variant are not generally stained with markers for nerve-origin cells, but are positively stained with NKI/C3, Ki-M1p, and CD68 [<xref ref-type="bibr" rid="ref4">4</xref>].</p> <p>The histological differencial diagnosis includes melanocytic tumor variants (e.g. Spitz Nevus), neurofibroma, schwannoma or neuroma variants [<xref ref-type="bibr" rid="ref2">2</xref>]. An atypical variant of NT has recently been described. It is described like a larger tumor (up to 6cm) of deep penetration (skeletal muscle and subcutaneous fat involvement), diffuse infiltrative borders, vascular invasion, a high mitotic index (>3 mitosis per 10 high power fields) and pleomorphism [<xref ref-type="bibr" rid="ref5">5</xref>].</p> <p>The real recurrence of NT is around 3%. Risk factors for recurrence are: myxoid type, being female, facial location, younger age at diagnosis, positive margins, and absence of fat-tissue in the sample [<xref ref-type="bibr" rid="ref3">3</xref>].</p> </sec> <sec id="sec1-2" sec-type="conclusion"> <title>CONCLUSION

Neurothekoma is a rare tumor. The diagnosis is based on histopathological and eventually immunohistichemical exam. The evolution is marked by the risk of recidive.

Consent

The examination of the patient was conducted according to the Declaration of Helsinki principles. Written informed consent was obtained from the patient for publication of this article

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