Oral HRAS Mutation in Orofacial Nevus Sebaceous Syndrome (Schimmelpenning-Feuerstein-Mims-Syndrome): A Case Report With a Literature Survey

Abstract

Background/Aim: The aim of this study was to present the long-term course of a patient with nevus sebaceous syndrome (NSS). Recent genetic studies place the syndrome in the emerging group of so-called RASopathies. The focus of the report is on surgical treatment and morphological and genetic findings of the face and oral cavity. Case Report: A female patient was treated for congenital alterations of facial skin and oral mucosa. The oral lesions were removed repeatedly. Eruption of teeth on the lesion sites was made easier by the measures taken. However, after repeated ablation of the affected gingiva, the periodontal papillomatous epithelium redifferentiated into the same reddish, conspicuous, hyperplastic epithelium. The teeth in the affected region showed noticeable changes in position, surface, and shape. A HRAS mutation was detected only in the regions of altered oral epithelia and not in adjacent soft tissues. Conclusion: Reports on NSS rarely address oral manifestations. The recorded alterations of oral soft and hard tissues in NSS indicate a topographical relationship between the development of oral mucosa and teeth as well as the long-lasting impact of a sporadic mutation on organ development at this site.Epidermal nevi (EN) are mosaic cutaneous developmental disorders (1-6). EN are differentiated according to the predominant epithelial cell types (7). The terminology of nevi refers to the histological components of the lesion (8). If extracutaneous findings are noted in addition to EN in an individual, this constellation is referred to as epidermal nevus syndrome (ENS) (1-6, 9-12). Some authors have used the term 'ENS' to describe a distinct entity, in particular (linear) nevus sebaceous syndrome (NSS) (synonymous: Schimmelpenning-Feuerstein-Mims (SFM) syndrome, Naevus sebaceous Jadassohn (syndrome), Solomon syndrome, and further terms) (1-6, 8, 10). Other authors subsumed a group of cutaneous diseases characterized by nevi and extracutaneous findings under the term 'ENS' (1, 10). Currently, the term 'ENS' is mostly used as an umbrella designation for several syndromes describing diseases with a potentially large variety of physical findings that frequently first attract attention through noticeable alterations in superficial skin layers, in particular nevi (3)(4)(5)8). With this broad sense, ENS also includes nevi that have adnexal differentiation (10). 274This article is freely accessible online.

Expansion of the complex genotypic and phenotypic spectrum of FGFR2-associated neurocutaneous syndromes

“…Despite intense analysis, we did not identify any likely causative variant. It is known that causative variants linked to SFM syndrome typically are detectable in the keratinocytes of the affected skin regions, but not in the fibroblasts underlying the altered epithelia (Friedrich et al 2022 ). To exclude that the percentage of affected cells in the biopsy might have been too low to detect the causative variant, we decided next to extract genomic DNA from a FFPE skin sample (mainly including keratinocytes of the affected lesion) and repeated the high-coverage custom-designed multigene panel including HRAS, KRAS, and NRAS (mean read depth of 6465 reads) .…”

Nevus Sebaceous Syndrome: A Case Report and Literature Review of the Associated Neurological Complications

“…Importantly, the earlier in embryogenesis they occur, the more widespread the nevus and the greater the chance (and more extensive and severe) of extracutaneous anomalies. Among patients diagnosed with NSS (which we consider identical to LNSS), HRAS mutations were the most common, including G13R [34,35,[48][49][50][51], G12C [25], G12S [26], and G13V [23], as were KRAS mutations, specifically G12D [14,22,24,25,26,27,30], G12V [28], G12C [20,53], and A146T [31]. One NRAS mutation (Q61R) was found, marking the first causative NRAS mutation in NSS [5], as well as unique mutations such as in the PRKRIR gene (A1674T, R558S) for one patient, and a mutation in the RRP7A gene (C670T, R224W) in another [27].…”