Renal Pelvis Squamous Cell Carcinoma Arising in the Setting of Long-Standing Nephrolithiasis: Clinicopathologic and Molecular Insights.
Ahmet Erbağci, Sıdıka Şeyma Özkanli, Sevil Albayrak et al.
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Case in brief
Two patients with decades-long renal stone disease developed squamous cell carcinoma of the renal pelvis. Both tumors showed extensive squamous metaplasia, moderately differentiated carcinoma with comedo-type necrosis, and aggressive local invasion; clinical outcomes were poor. Immunohistochemistry showed diffuse p63, p40, and keratin 5/6 expression, aberrant p53 patterns, p16 negativity, and high PD-L1 expression (CPS 85 and 72.5). Both tumors had TP53 alterations; one also had a TERT promoter mutation (C228T) and was associated with early distant metastases.
What made this case unusual
Both tumors had strikingly high PD-L1 expression, and one carried a TERT promoter mutation associated with early distant metastases.
Diagnostic / clinical pearl
In renal pelvis tumors arising with long-standing nephrolithiasis, extensive squamous metaplasia and a squamous immunophenotype can support recognition of SCC; the reported tumors also showed aggressive invasion and poor outcomes.
Why it matters
The authors suggest that PD-L1 expression may be relevant to immune checkpoint inhibition, although these two cases do not establish treatment benefit.