Update on Superficial Spindle Cell Mesenchymal Tumors in Children

The diagnosis of cutaneous and subcutaneous spindle cell neoplasms in children is often challenging has potential therapeutic prognostic implications. Although correctly diagnosing dermatofibrosarcoma protuberans infantile fibrosarcoma paramount, pathologists should not ignore a number diagnostic pitfalls linked to mostly rare tumors with completely different clinical outcomes. In the last decade, spectrum novel entities been described; information from molecular biology helped shape this new landscape for tumors. Here, we review most noteworthy spectrum, focus on their histological similarities: fibroblastic connective tissue nevus, medallion-like dermal dendrocyte hamartoma, or plaque-like CD34-positive fibroma, which share features fibrous hamartoma infancy; lipofibromatosis lipofibromatosis-like neural tumor; plexiform myofibroblastoma, recently described neoplasm that be distinguished fibrohistiocytic tumor. These also have genetic similarities, particularly gene rearrangements involving NTRK3 NTRK1. are only essential differential but value more RET, RAF1, BRAF fusions discussed.