Answer of Dermatopathology Case 12

Trichoepithelioma

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Abstracts:

A novel missense mutation of CYLD gene in a Chinese family with multiple familial trichoepithelioma. Arch Dermatol Res. 2009
Multiple familial trichoepithelioma (MFT, OMIM 601606) is an autosomal dominantly inherited disease. It is characterized by numerous skin-colored papules on the central face. Pathogenic mutations in the CYLD gene have been identified. In this report, we identified a novel mutation of CYLD gene in a Chinese family with MFT. It is a novel heterozygous nucleotide G-->A transition at position 2,317 in exon 17 of the CYLD gene. Our study expands the database on the CYLD gene mutations in MFT.

Trichoepithelioma of the vulva: report of a case and review of the literature.J Low Genit Tract Dis. 2009
Trichoepithelioma is a rare benign skin lesion arising from hair follicles. It most commonly arises on the face and scalp. It is exceptionally rare on the vulva. We present a case and review the literature.

Advanced differentiation in trichoepithelioma and basal cell carcinoma investigated by immunohistochemistry against neurofilaments.Folia Histochem Cytobiol. 2009;
Basal cell carcinoma (BCC) and trichoepithelioma (TE) are sometimes diagnostic challenges for the pathologist in terms of their differential diagnosis. Although literature is quite rich in information about histologic and immunohistochemical clues to distinguish the differences between both, no single finding must be completely reliable. Moreover, some consider that TE is a better differentiated follicular tumour, while BCC represents a less developed stage indifferentiation. For instance, the latter opinion is supported by the evidence of follicular papillae in TE.The formation of a perifollicular nerve plexus happens later than the formation of the follicular papillae in the development of a normal follicle. The study of the presence of the perifollicular nerve plexus in both tumours which could then provide us with evidence on the stage of differentiation of both tumours. 5 cases of TE and 10 cases of BCC were randomly selected from our archives and an immunohistochemical study for neurofilaments was performed in all the cases. We found a peritumoural nerve plexus in all the cases (TEs and BCCs). Since this plexus is a late sign of differentiation andsince both types of neoplasias share it, we conclude that TE and BCC are both terminally differentiated neoplasms. The ability of BCC to infiltrate would have more to do with the acquisition by the tumour of such a property, rather than with a stage of indifferentiation.

A novel splicing mutation of the CYLD gene in a Taiwanese family with multiplefamilial trichoepithelioma.Clin Exp Dermatol. 2009
Multiple familial trichoepithelioma (MFT) is an autosomal dominant disease characterized by numerous skin-coloured papules on the central face. Mutations inthe CYLD gene, which is also the gene responsible for familial cylindromatosis,have been reported recently. Recent studies indicate that CYLD is a tumour-suppressor gene. The CYLD protein is a negative regulator of theactivation of transcription factor nuclear factor-kappaB, and loss of CYLDcontributes to oncogenesis. We report a novel splicing mutation (IVS12 + 1 G-->A) in the CYLD gene in a Taiwanese pedigree with MFT, and discuss new developmentsin treatment options.

Trichoepithelioma.Dermatol Online J. 2008 Oct 15;14(10):5.
A 29-year-old man presented with a long-standing history of asymptomatic,skin-colored, facial papules and nodules. Histopathologic examination of arepresentative papule demonstrated trichoepithelioma. The patient had a historyof a brother with a similar phenotype, which suggests a diagnosis of familialtrichoepithelioma. Linkage and mutational analyses support genetic heterogeneity of familial trichoepithelioma, possibly sharing a clinical spectrum withBrooke-Spiegler syndrome and familial cylindromatosis since each entity has been associated with mutations the CYLD gene.

Elastic fiber staining and cytokeratin 15 expression pattern in trichoepithelioma and basal cell carcinoma. J Dermatol. 2008 Aug;35(8):499-502.
Trichoepithelioma (TE) is a benign neoplasm of the skin that resembles basal cell carcinoma (BCC) in its clinical and histological features. In this study, we evaluate the usefulness of elastic fiber staining and cytokeratin 15 expression pattern in terms of distinguishing TE from BCC. Eleven TE and 17 BCC were examined histochemically and immunohistochemically. It was found that BCC containmore elastic fiber than TE, and that more TE show peripheral localization than BCC in cytokeratin 15 expression patterns. The present study shows that elasticfiber staining and cytokeratin 15 expression pattern may aid the differentiation of TE from BCC.