p63 is a useful marker for cutaneous spindle cell squamous cell carcinoma.
BACKGROUND
Cutaneous spindle cell squamous cell carcinoma (SCSCC) is a rare variant of SCC. This lesion is sometimes difficult to diagnose based purely on morphologic features. p63 is a member of the p53 gene family that can be identified in epithelial malignancies.


METHODS
Thirteen cases of spindle SCC were stained with p63, CK34betaE12, MNF116, vimentin, and S100. Control cases included desmoplastic melanoma (eight cases), atypical fibroxanthoma (AFX) (10 cases), dermatofibrosarcoma protuberans (eight cases), and cutaneous leiomyosarcoma (LMS) (four cases).


RESULTS
p63 was expressed diffusely in the nuclei of 100% (13/13) of SCSCCs. Of controls, p63 showed focal labeling of two LMS and two AFX. MNF116 and CK34betaE12 were positive in 13/13 SCSCCs. Of controls, one LMS was focally positive for MNF116. All SCSCCs and all control cases were positive for vimentin.


CONCLUSIONS
In the given differential diagnosis, p63 appears relatively specific to SCSCC and adds a useful nuclear marker to the available repertoire. The findings also suggest that cytokeratins MNF116 and CK34betaE12 may be more useful than standard cytokeratins in labeling SCSCC.
Dotto
Jorge E
JE
Department of Pathology, Dermatopathology, Yale University School of Medicine, New Haven, CT 06520-8023, USA.
Glusac
Earl J
EJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000276:immunology / Q000378:metabolism; D018223:Dermatofibrosarcoma / Q000175:diagnosis / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007890:Leiomyosarcoma / Q000175:diagnosis / Q000378:metabolism; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000378:metabolism; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism*; D008875:Middle Aged; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014973:Xanthomatosis / Q000175:diagnosis / Q000378:metabolism
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D008565:Membrane Proteins