Protrusions Within a Pink-Yellow Plaque

Case Presentation

A 74-year-old woman with a history of several skin tumors was referred to our center. She complained of a lesion localized on the right flank, growing for 15 months. Upon examination, a 75 mm × 30 mm pinkish-yellowish plaque was observed. Within the lesion, three red, firm, keratotic papules were seen (Figure 1A). Dermoscopy showed yellow globules with indistinct borders on a whitish-erythematous background. In the yellowish structures, polymorphous vessels consisting of linear irregular vessels and curved vessels were seen. Within the papules hairpin, coiled vessels were present (Figure 1, B–D).

Figure 1.

(A) Clinical picture of the lesion. (B-D) Dermoscopy demonstrated white-pink areas with yellow structures throughout the lesion with polymorphous vessels (arrows)

Due to the large size, an incisional biopsy was performed. Histopathology revealed the collision of an in-situ squamous cell carcinoma and superficial sebaceous carcinoma (SC). The lesion was excised with safety margin. Pathology confirmed the previous diagnosis.

Teaching point

Sebaceous carcinoma tends to mimic squamous and basal cell carcinomas. The presence of yellowish structures and polymorphous vessels are features suggestive of SC. Some suggest that extraocular SC might originate from preexisting intraepidermal squamous neoplasia [1,2].