Pink nodule accompanied with clustered yellow globules at the periphery.

Clinical presentation

A 75-year-old woman sought treatment for an erosive, pink nodule behind her left ear that had begun bleeding 1 year prior. A benign lesion had existed in the region since birth. The ulcerated nodule was 3 cm in maximum diameter and surrounded by small blue-gray nodules on visual inspection (Fig 1).

Fig 1

Clinical image of basal cell carcinoma arising in nevus sebaceous.

Dermoscopic appearance

Dermoscopic examination revealed polymorphous vessels in the pink nodule and multiple blue-gray globules along the border. Of particular interest was an aggregation of small, yellow globules detected at the periphery of the lesion (Fig 2).

Fig 2

Dermoscopic images of basal cell carcinoma arising in nevus sebaceous. Arrows indicate polymorphous vessels. Arrowheads indicate blue-gray globules. Asterisk indicates clustered, yellowish globules. (Original magnification: ×10.)

Histologic diagnosis

Histologic findings confirmed a diagnosis of basal cell carcinoma arising from nevus sebaceous (Fig 3).

Fig 3

Histopathologic features of basal cell carcinoma arising in nevus sebaceous. A, In the pink nodule, basaloid tumor cells with atypia have proliferated throughout the dermis in a nest formation. B, An increased number of mature sebaceous glands are present in the dermis of the area where the yellowish globules were observed by dermoscopy. (A and B, Hematoxylin-eosin stain; original magnification: ×20; inset, ×400.)

A pink nodule with polymorphous vessels is a dermoscopic finding indicative of melanoma or another malignant neoplasm. However, there were 2 dermoscopic clues in this case unsupportive of melanoma. One was multiple blue-gray globules that were characteristic of basal cell carcinoma but could not be completely differentiated from those of melanoma. The other dermoscopic feature was the clustered yellow globules at the lesion periphery. Yellow, lobular-like structures suggest sebaceous tumors. Taken together with the patient's clinical history and dermoscopic findings, the earlier lesion in this case was judged to be nevus sebaceous. Accordingly, basal cell carcinoma was strongly suspected as it was the most frequent malignant neoplasm arising in nevus sebaceous.