Useful histological features for distinguishing between sebaceoma and basal cell carcinoma with sebaceous differentiation
| Feature | Sebaceoma | BCC with sebaceous differentiation |
|---|---|---|
| BCC, basal cell carcinoma. | ||
| Overall morphology | Similar to sebaceous adenoma, but with more basaloid component | Similar to classical BCC, but with a component of sebaceous differentiation |
| Main components | Aggregates of basaloid germinative cells admixed with single units or clusters of mature vacuolated sebocytes | Aggregate of follicular germinative basaloid cells |
| Architectural pattern | Benign | Malignant |
| Cytological features | Monomorphous basaloid cells, with small oval nuclei and non-prominent nucleoli | Pleomorphic basaloid cells, with slightly elongated nuclei |
| Mitotic activity | Mild/absent | Brisk |
| Sebaceous differentiation | Prominent | Focal and associated with apocrine differentiation in many cases |
| Peripheral palisading | Usually absent | Present |
| Artefactual clefting | Absent | Often present |
| Basaloid tumour necrosis | Rare | Frequent |
| Other associated features | Sebaceous duct-like structures, rare squamous differentiation, and dense eosinophilic dermal sclerosis | Sebaceous duct-like structures, individual cell necrosis, keratinization and mucinous stroma |