Interactive Case Study - December 2023

28-year-old man with an arm mass

Jill Browning, MD; Rami Al-Rohil, MBBS

A 28-year-old man presented with a two-month history of an irritating small nodule on his left proximal forearm. Clinically, the lesion was thought to be a cyst, and it was removed via punch biopsy.

Click this image to view the virtual slide:

Figure 1: H&E 2x

Figure 2: H&E 4x

Figure 3: H&E 20x

Figure 4: H&E 40x

Figure 5: H&E 40x

Figure 6: H&E 40x

Figure 7: AE1AE3 IHC 4x

Figure 8: CD34 IHC 4x

Figure 9: ERG IHC 40x

What is the best diagnosis?

A.	Dermatofibrosarcoma protuberans

B.	Epithelioid hemangioendothelioma

C.	Epithelioid sarcoma

D.	Pseudomyogenic hemangioendothelioma

E.	Superficial CD34-positive fibroblastic tumor