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BackgroundDesmoplastic trichoepithelioma (DT) is a benign appendageal tumour predominately localized on the facial skin. The histological diagnosis can be difficult in some cases. Partial malignant transformation of a DT is a rarity and a complete transformation has never been described in literature.Case reportA DT of the upper lip was diagnosed histologically by a small biopsy 4 years previously. At presentation, the tumour had enlarged and had partly infiltrated the left side of the upper lip and subnasal region. Histological evaluation confirmed a microcystic adnexal carcinoma but without evidence of malignant transformation of the DT. It appeared that a too-small initial biopsy had led to the incorrect histological diagnosis of a benign tumour. Thus, it was necessary to perform a tumour resection and reconstruction using a two-flap technique including a rotation flap and an Abbé flap. Functional and aesthetic outcomes were good after 6 months. There were no recurrences during a 12-month follow-up.ConclusionA facial DT should be resected completely. Patients should be attended for follow-ups, keeping in mind the difficulty of making a proper histological diagnosis from small biopsies or excisions and the consequences of ablative facial surgery. However, in particular cases, subtotal defects of the upper lip region are amenable to reconstruction without gross functional or aesthetic deficits.

The subperiosteal dental implantation implant was orginally described in the 1940s. The inadequate long-term results of subperiosteal implants are in contrast to the excellent results documented for endosseus oral implants. Consequently, subperiosteal implants and other soft-tissue-anchored implants should not be used presently. The present report documented twelve patient cases with complications after treatment with subperiosteal implants. Typical complications of SI are implant exposure, inflammation, infection, fistula formation and implant mobility. After removing the SI severe atrophic bone was seen. The placement of osseointegrated oral implants was mostly not possible without autogenous bone grafting. The present report is in conclusion with other studies, that a regular control of patients with subperiosteal implants is necessary. Subperiosteal implants should definitely be removed, if continuous periods of complication occur. The complete oral rehabilitation requires further surgical treatment in the field of preprosthetic surgery.

After interdisciplinary treatment, mutilation was avoided after exenteration of the orbit or radiation treatment to the growing facial skeleton. That was possible due to excision of the residual tumor in a second step, leading to down-staging of the RMS.