Knee Desmoplastic Melanoma, an Uncommon Tumor, Disguised as a Malignant Peripheral Nerve Sheath Tumor: A Case Report and Review of the Literature

Abstract

Desmoplastic melanoma is a rare and distinct subtype of cutaneous melanoma, it presents diagnostic challenges due to the lack of specific clinical features and overlapping histopathological characteristics with other malignancies, which necessitate careful clinicopathological correlation and advanced immunohistochemical profiling. While surgical excision remains the cornerstone of treatment, advances in precision medicine, particularly immune checkpoint inhibitors, have shown promise in improving outcomes for unresectable and metastatic desmoplastic melanoma. We present a case study involving a 52-year-old woman misdiagnosed with a malignant peripheral nerve sheath tumor and later identified as desmoplastic melanoma through re-evaluation of histopathological and immunohistochemical findings. The patient underwent surgical resection followed by adjuvant radiotherapy and showed favorable locoregional development.