PMC4809445_01
A and B, The original excision (April 2012) yielded a predominantly well-differentiated cSCC with abundant keratin and an associated marked giant cell reaction. Minimal foci of moderate differentiation were present. Tumor closely abutted small cutaneous nerves multifocally. Retrospective S100 protein immunostain confirmed absence of perineural invasion at this time.
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fig1
The original tumor biopsy, first excision, and subsequent tumor excisions all share a highly reproducible pattern of giant cell reaction and granulomalike inflammation associated with the keratinizing component, occurring as "skip" areas laterally and deep in relation to the surface (Fig 1).
The subsequent recurrences (March 2015) were histologically similar. A, Obliterated nerve. B, The cutaneous components include the identical abundant keratin and the associated giant cell reaction.
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fig2
The giant cell reactive clusters persist even in the later deep tumor masses associated with large nerves involved by otherwise moderately to poorly differentiated squamous cell carcinoma (Fig 2).