Desmoplastic Spitz Nevus of the Thigh in a Young Woman: Clinical Presentation and Histopathological Diagnosis

Desmoplastic Spitz nevus is an uncommon variant within the spectrum of spitzoid melanocytic tumors and represents a well-known diagnostic challenge due to its histopathological resemblance to desmoplastic melanoma, a malignant entity associated with poor prognosis. We report the case of a 35-year-old woman who presented with a small, erythematous, firm nodule on the right thigh with progressive growth over four months. Complete surgical excision was performed. Histopathological examination revealed a dermal melanocytic proliferation composed of Spitz-type cells arranged in nests and sheets within a markedly desmoplastic stroma, with evidence of maturation in depth and absence of significant cytologic atypia or mitotic activity. Surgical margins were free of involvement, and the findings were consistent with a desmoplastic Spitz nevus. This case highlights the importance of recognizing the distinctive clinical and histopathological features of desmoplastic Spitz nevus to avoid misdiagnosis and unnecessary aggressive treatment. Accurate differentiation from desmoplastic melanoma is essential, and in ambiguous cases, immunohistochemical studies may be required to support the diagnosis.