Pleomorphic basal cell carcinoma.

BACKGROUND: A variant of basal cell carcinoma (BCC) with scattered large, pleomorphic cells has previously been reported as "basal cell epithelioma with giant tumor cells" and "basal cell carcinoma with monster cells." OBJECTIVE: Our purpose was to describe the clinical, histologic, and DNA ploidy findings in BCCs with these cytologic features. METHODS: Nineteen pleomorphic BCCs from 15 patients were prospectively collected, and other BCCs in these patients were retrospectively reviewed by light microscopy. One lesion was recurrent. Seven of the pleomorphic BCCs and one nonpleomorphic BCC were studied by image analysis. RESULTS: These pleomorphic BCCs ranged from 2.8 to 12.5 mm in greatest diameter and were most commonly located on the head and neck. Five BCCs were present on the face and scalp of a patient with basal cell nevus syndrome. There have been no subsequent recurrences of the pleomorphic BCCs (follow-up from 3 to 32 months; median, 20 months). All 19 pleomorphic BCCs displayed characteristic features of BCC: peripheral palisading, stromal retraction, mucin production, and apoptosis. All 19 also showed huge pleomorphic mononucleated and multinucleated giant tumor cells. The nuclei of these large cells were often hyperchromatic with prominent nucleoli and abundant cytoplasm, and occasionally with intranuclear cytoplasmic protrusions. In addition, there were frequent and atypical mitoses in 47% of the cases. All pleomorphic BCCs studied by cell image analysis of formalin-fixed, paraffin-embedded tissue were aneuploid. The DNA content of the giant tumor cells was not a multiple of a single DNA value. CONCLUSION: Pleomorphic BCCs clinically present as typical BCCs. Despite their striking focal cellular atypia, these lesions seem to behave as ordinary BCCs.