Background:
Sebaceous adenomas are found mainly in elderly individuals and are usually tan, pink, or yellow nodules or papules, usually approximately 5 mm in the largest size.
Case report:
A 65-year-old man presented with a progressively enlarging exophytic lesion in the right eyelid for 3 months. External examination revealed a yellowish-pink growth measuring 18 × 13 × 14 mm. The lesion surface was covered by palpebral conjunctiva with fine papillary projections, vascularity, crusting, and ulceration. Two weeks later, the growth enlarged to 20 × 14 × 14 mm, and ulceration also expanded. An excisional biopsy with clear resection margins was performed. No malignancy was found in the stump. Histopathologically, the lesion was located principally within the cutaneous compartment and composed of multiple circumscribed sebaceous lobules, separated, and exhibiting no cytologic atypia. Cystic change was not evident, and no infiltrative growth pattern, pagetoid lesions, mitotic figures, and lymphovascular space invasion were observed. The Ki-67 nuclear antigen was detected in 10%-15% of cells located in the basal zone of the nodule. Fluorescence in situ hybridization showed low human epidermal growth factor receptor 2 amplification, suggesting no genetic changes. The clinical findings, lack of infiltrative border, low Ki-67 index, and low proliferative ability support a diagnosis of sebaceous adenoma.
Conclusion:
Sebaceous adenoma that shows excessively rapid growth due to hyperplasia may appear to be malignant. Histopathology, fluorescence in situ hybridization, and Ki-67 were useful to the diagnosis of the adenoma. Excisional biopsy with clear resection margins must be performed in rapidly growing tumors.