Summary
Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma characterized by slow growth but significant local infiltrative potential and a high risk of recurrence, while fibrosarcomatous transformation represents an event associated with increased biological aggressiveness and metastatic capacity [1,2]. In parallel, the occurrence of multiple primary cutaneous melanomas constitutes a relatively rare phenomenon, suggesting increased individual susceptibility determined by genetic, immunologic, or environmental factors [6,15]. The coexistence of these two histogenetically distinct neoplastic entities in the same patient is uncommon and raises significant challenges in diagnosis, staging, and ther-apeutic management.
We present the case of a 56-year-old patient with a history of dermatofibrosarcoma protuberans initially diagnosed in 2015, subsequently complicated by local recurrence and pulmonary metastasis histopathologically confirmed as DFSP with fibrosarcomatous transformation, treated with targeted therapy using imatinib [3,8], with favorable evolution under treatment. During oncologic surveillance, the patient successively developed three distinct melanocytic neoplasms: melanoma in situ (2017), ulcerated primary cutaneous melanoma (2024, stage IIB [6,12]), and a melanocytic tumor initially diagnosed as MELTUMP (Melanocytic Tumor of Uncertain Malignant Potential), later reclassified following histopathological and immunohistochemical reassessment as non-ulcerated primary cutaneous melanoma (pT2a). Sentinel lymph node biopsy of the latter lesion revealed suspicious subcapsular melanocytic proliferation, subsequently confirmed by immunohistochemistry as a capsular melanocytic nevus, with no evidence of nodal metastasis, resulting in a final stage IB. Molecular analysis revealed absence of BRAF mutation, with prognostic and therapeutic implications [11].
This case highlights the complexity of differential diagnosis in borderline melanocytic lesions, the importance of histopathological reassessment in specialized centers, and the essential role of clinicopathologic and immuno-histochemical correlation in avoiding staging errors. It also underscores the need for rigorous multidisciplinary monitoring in patients with multiple primary cutaneous neoplasms to optimize therapeutic management and long-term prognosis.
