Atypical fibroxanthoma
LEGEND
Low-grade cutaneous sarcoma
Poorly defined tumor located in the dermis
Pleomorphic neoplastic process composed of spindle and epithelioid cells
Atypical fibroxanthoma
LEGEND
- Nuclear pleomorphism (irregular nuclei with multiple nucleoli and variable size)
Atypical fibroxanthoma
- Immunohistochemistry: diffusely positive for vimentin
Atypical fibroxanthoma is a diagnosis of exclusion. Immunohistochemical studies must be performed to rule out other tumors that may present as spindle cell proliferations.
DDx mnemonic SLAM
S for Spindle cell squamous cell carcinoma (keratin 5/6+ and p63+)
L for Leiomyosarcoma (smooth muscle actin+ and desmin+)
A for Atypical fibroxanthoma (CD10+ and vimentin+)
M for Melanoma (S100+, Melan-A+, and SOX10+)
