What is the Difference Between Dermatofibroma and Dermatofibrosarcoma?

Dermatofibroma and dermatofibrosarcoma protuberans (DFSP) are both skin conditions, but they have distinct differences in terms of their nature, clinical presentation, and treatment.

Dermatofibroma:

• A benign skin growth
• Generally appears as a nodule, approximately 2 cm in diameter, on the lower limbs
• Rarely requires treatment

Dermatofibrosarcoma Protuberans (DFSP):

• An intermediate-grade, locally invasive soft-tissue sarcoma
• Often appears on the trunk or shoulder with irregularly arranged plaques or nodules larger than 5 cm
• Always requires treatment

Histologically, dermatofibroma shows a regular silhouette with a smooth, homogeneous appearance. In contrast, DFSP has a more chaotic and invasive appearance, with nuclei that resemble a "puck" or "coin" shape in three dimensions.

Immunohistochemical stains, such as cluster of differentiation 34 (CD34) and Factor XIIIa, can be used to distinguish between the two entities, but these markers are not entirely sensitive or specific. A predominant alternating ovoid-spindled nuclear morphology is found to be highly specific (Sp = 1) and sensitive (Sn = 0.98) for DFSP, making it a more reliable diagnostic tool.

Comparative Table: Dermatofibroma vs Dermatofibrosarcoma

Here is a table comparing the differences between dermatofibroma and dermatofibrosarcoma:

Dermatofibromas are benign slow-growing tumors with a storiform pattern, while dermatofibrosarcoma protuberans is a low- to intermediate-grade malignant soft-tissue tumor with a high local recurrence rate but low metastatic potential. Both tumors have a similar histomorphology and immunophenotype, but the latter is more invasive and requires wider excision or Mohs micrographic surgery for treatment.