Atypical fibroxanthoma and pleomorphic dermal sarcoma: a 10-year retrospective study and review of the literature

J. Joana Vieitez-Frade, Department of Dermatology, Hospital de Santa Maria, Unidade Local de Saúde Santa Maria, Lisbon, Portugal; Dermatology University Clinic, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal Dora Mancha, Department of Dermatology, Hospital de Santa Maria, Unidade Local de Saúde Santa Maria, Lisbon, Portugal; Dermatology University Clinic, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal Pedro Vasconcelos, Department of Dermatology, Hospital de Santa Maria, Unidade Local de Saúde Santa Maria, Lisbon, Portugal Luís Soares-de-Almeida, Department of Dermatology, Hospital de Santa Maria, Unidade Local de Saúde Santa Maria, Lisbon, Portugal; Dermatology University Clinic, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Dermatology Research Unit, iMM Joao Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal Paulo Filipe, Department of Dermatology, Hospital de Santa Maria, Unidade Local de Saúde Santa Maria, Lisbon, Portugal; Dermatology University Clinic, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Dermatology Research Unit, iMM Joao Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal

Objectives: To characterize the demographic, clinical, histopathological, therapeutic, and prognostic features of patients diagnosed with atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) in a tertiary center. Methods: Retrospective observational study conducted from January 2014 to December 2023 at the Dermatology Department of Unidade Local de Saúde Santa Maria. Patients with histological diagnoses of AFX or PDS were included. Results: A total of 22 male patients, all over 65 years old, were included. Most tumors were located on the head (91%), measured < 2 cm (59%), and presented as non-specific plaques, nodules, or tumors, occasionally ulcerated. Histological criteria used to distinguish AFX (73%) from PDS (27%) included adipose tissue invasion (27%), neurotropism (5%), and necrosis (23%). All patients underwent initial surgical excision, five with positive margins. Three PDS patients received adjuvant radiotherapy (RT). One patient had a local recurrence, two patients developed regional metastases, and one patient developed a distant metastasis, all in PDS cases. No disease-related deaths were reported. Conclusions: AFX and PDS are rare cutaneous tumors with similar clinical presentations but distinct prognostic outcomes. Immunohistochemistry plays a critical role in differential diagnosis. Surgery remains the gold-standard treatment, while RT may benefit selected PDS cases. Further studies are needed to standardize therapeutic strategies and establish clear follow-up guidelines for these patients.

Keywords: Atypical fibroxanthoma. Pleomorphic dermal sarcoma. Mesenchymal tumors. Immunohistochemistry. Wide surgical excision. Adjuvant radiotherapy.