Exploring the Uncommon: A Series on Dermatofibrosarcoma Protuberans with Rare Locations, Unusual Sites of Metastasis, and Their Close Mimics

Abstract Dermatofibrosarcoma protuberans (DFSP) is an uncommon, slowly growing soft-tissue tumor that involves the dermis, subcutaneous fat and very rarely involves, muscle and deep fascia. It is locally aggressive and an intermediate-grade fibroblastic neoplasm that rarely metastasizes. It is important to know about this entity as it is locally aggressive and has a higher rate of transformation into fibrosarcoma which has an aggressive growth pattern and frequently metastasizes. Apart from this, there are diagnostic challenges, especially in small biopsies, where they resemble other spindle cell neoplasms. This article reviews the clinical and histological features of DFSP as well as possible pitfalls in their diagnosis and how to resolve them. Diagnosed cases of DFSP were retrieved from pathology archives. Their locations and histopathological features along with Immunohistochemistry (IHC) features were reviewed. Our study identified 26 cases of DFSP for 5 years from January 2019 to January 2024 in a tertiary care hospital. The age of study subjects was in the range of 11–70 years. Male:female ratio was 1.30:1. The most common site was shoulder ( n = 5). Immunohistochemistry (HC) was performed in cases with diagnostic dilemmas and cases of high-grade transformation. The aim of this study was to perform a retrospective analysis of histopathological features of DFSP to distinguish it from other mimics and emphasize its local aggressiveness, reoccurrence, and rare site of metastasis, especially in cases with fibrosarcomatous transformation. The careful histomorphological examination particularly in smaller biopsies can be challenging, especially in peripheral laboratories and in resource-limited settings.