Rare Mucosal Lip Atypical Fibroxanthoma Treated with Mohs Micrographic Surgery

Atypical fibroxanthoma (AFX) is a rare dermal neoplasm of low-intermediate malignant potential found almost exclusively in the non-mucosal regions of the head and neck in light-skinned elderly males who have a history of significant sun exposure. Due to its risk of misdiagnosis of more common skin lesions and possibility of metastases, AFX requires resection with either Mohs Micrographic Surgery (MMS) or wide local excision (WLE). The purpose of this abstract is to discuss the best comprehensive treatment for a lower lip AFX using MMS versus WLE.

An Unusual Case of Desmoplastic Melanoma With Monster Cells Imitating an Atypical Fibroxanthoma

Numerous cells with very large and irregular nuclei (“monster” cells) have not hitherto been reported in desmoplastic melanoma (DM). Their prognostic significance in melanomas is a matter of debate, although some authors have associated them with more aggressive tumor behavior. We report a mixed DM on the scalp of an 88-year-old woman imitating an atypical fibroxanthoma. Tumor cells stained positive for SOX10, S100, and cyclin D1; BRAF mutation status was negative, and fluorescence in situ hybridization analysis showed copy number gains in 11q13 (cyclin D1) and 6p25 (RREB1), and loss in 6q23 (MYB). Cyclin D1 amplification is associated with poor prognosis in melanoma.

Atypical fibroxanthoma of hand

Atypical fibroxanthoma (AFX) is a rare cutaneous ulcerative lesion with a good prognosis. Diagnosis is difficult and is usually made by exclusion from pleomorphic dermal sarcoma and squamous cell carcinoma. Definitive treatment varies from Mohs micrographic surgery to wide local excision. We present a case of 76-year-old woman with AFX over the dorsum of her left hand. The tumour was excised and the resulting defect was reconstructed with a local second dorsal metacarpal artery perforator flap.

Clinicopathological and Genomic Profiles of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma Identify Overlapping Signatures with a High Mutational Burden

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare tumors developing in chronically sun-exposed skin. Clinicopathological features are similar, but they differ in prognosis, while PDS has a more aggressive course with a higher risk for local recurrence and metastases. In current clinical practice, they are diagnosed by exclusion using immunohistochemistry. Thus, stringent diagnostic criteria and correct differentiation are critical in management and treatment for optimal outcomes. This retrospective single-center study collected clinicopathological data and tumor samples of 10 AFX and 18 PDS. Extracted genomic DNA from tumor specimens was analyzed by a next-generation sequencing (NGS) platform (FoundationOne-CDx™). Among 65 identified mutations, TP53 inactivating mutations were observed in all tumor specimens. In both AFX and PDS, the known pathogenic gene alterations in CDKN2A, TERT promoter, and NOTCH1 were frequently present, along with high mutational burden and stable Micro-Satellite Instability status. The mutational profiles differed only in ASXL1, which was only present in AFX. Further differences were identified in likely pathogenic and unknown gene alterations. Similarities in their genomic signatures could help to distinguish them from other malignancies, but they are not distinguishable between each other using the FoundationOne-CDx™ NGS panel. Therefore, histological criteria to determine diagnosis remain valid. For further insight, performing deep tumor profiling may be necessary.

Spontaneous Regression of Atypical Fibroxanthoma of the Hand

Atypical fibroxanthoma is a rare fibrohistiocytic tumour with intermediate malignancy that generally affects photoexposed areas of the elderly. The diagnosis is anatomopathological and the management is surgical. We report the case of a spontaneous regression of an atypical fibroxanthoma of the hand. This phenomenon is a very rare situation related to a probable immunological response.