Psammomatous Squamous Cell Carcinoma of the Skin.

Psammoma bodies (PBs) are concentric, lamellated calcifications commonly observed in malignancies such as papillary thyroid carcinoma and serous carcinoma of the ovary in which they may serve prognostic value. PBs are rare in cutaneous squamous cell carcinoma (cSCC), with only I previously reported case. Here, we present 3 cases of cSCC displaying PBs. One case occurred in the setting of end-stage renal disease, whereas the other 2 cases were in patients who did not have comorbid conditions that might predispose to hypercalcemia and dystrophic calcification. All 3 tumors demonstrated classic immunophenotypic findings of cSCC. Our findings indicate that PBs are a rare but recurrent phenomenon in cSCC, with unknown prognostic significance. The potential for PB formation in cSCC should be kept in mind, as this may represent a diagnostic pitfall in tumors with limited sampling or unusual morphologies.