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Expression of the p40 isoform of p63 has high specificity for cutaneous sarcomatoid squamous cell carcinoma
Author(s) -
Ha Lan Thanh T.,
Chen Stephanie J. T.,
Arps David P.,
Fullen Douglas R.,
Patel Rajiv M.,
Siddiqui Javed,
Carskadon Shan,
Palanisamy Nallasivam,
Harms Paul W.
Publication year - 2014
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.12387
Subject(s) - sarcomatoid carcinoma , atypical fibroxanthoma , pathology , immunostaining , immunohistochemistry , staining , medicine , cell , biology , genetics
Cutaneous spindle cell malignancies such as sarcomatoid squamous cell carcinoma ( SCC ), leiomyosarcoma, desmoplastic melanoma ( DM ) and atypical fibroxanthoma ( AFX ) may be morphologically indistinguishable, yet accurate diagnosis is important for appropriate clinical management. The distinction among these entities relies on immunohistochemical evaluation for epidermal, muscle or melanocytic differentiation. Epidermal differentiation markers include cytokeratins and p63. p63 is expressed as two distinct isoforms, ΔNp63 (p40) and TAp63 . p40 positivity is highly specific for pulmonary SCC and head and neck sarcomatoid SCC . We examined the utility of p40 vs. p63 immunostaining in the differentiation of a variety of cutaneous spindle cell malignancies, including sarcomatoid SCC (n = 27), AFX (n = 34) and DM (n = 10). p40 was less sensitive than p63 for detecting sarcomatoid SCC (56% and 81%, respectively). p63 and p40 were comparably specific for sarcomatoid SCC relative to AFX , with only rare weak staining of tumor cells for p63 and/or p40 in a minority of AFX cases, including one case with approximately 10% of cells staining weakly for p40. All cases of DM were negative for p40 and p63. Our results support continued use of p63 for diagnosis of cutaneous sarcomatoid SCC because of greater sensitivity relative to p40.