Abstract
Both seborrheic keratosis and basal cell carcinoma are common skin tumors in daily clinical practice. However, the coexistence of seborrheic keratosis and basal cell carcinoma is rare. In this report, we present a case of occult microscopic basal cell carcinoma arising in a lesion of seborrheic keratosis. This case indicates that the basal cell carcinoma could arise from seborrheic keratosis and might help to clarify the origin of basal cell carcinoma.
Key Words: Basal cell carcinoma, Seborrheic keratosis, Coexistence
Case Presentation
A 65-year-old man visited our department complaining of a lesion on the right buttock. He had recognized the lesion 2 years previously, and it had gradually enlarged. There was no past medical history. On examination, there was a 0.8 × 0.7-cm well-defined, brown nodule on the right buttock (Fig. 1). Although the dermoscopic findings coincided with those of benign seborrheic keratosis, the lesion was excised in accordance with his wishes. Histologically, the lesion exhibited epidermal cell proliferation accompanied by hyperkeratosis, papillomatosis, and inflammatory cell infiltration, which was compatible with irritated seborrheic keratosis. Nests of basaloid cells with peripheral palisading and surrounding cleft were attached to the lesion of seborrheic keratosis (Fig. 2). In an immunochemical study, strong positive staining for Ber-EP4, a useful marker of basal cell carcinoma, was found in the basal cell carcinoma area, but not in the seborrheic keratosis area (Fig. 3). After diagnosing basal cell carcinoma in seborrheic keratosis, no additional procedure was performed as the lesion had been adequately removed.
Fig. 1.
Well-defined lesion on the right buttock.
Fig. 2.
Nests of basaloid cells with peripheral palisading and surrounding cleft were attached to seborrheic keratosis. H&E staining. ×40.
Fig. 3.
Basal cell carcinoma was selectively positively stained with Ber-EP4. Immunostaining. ×40.
Discussion
The precise origin of seborrheic keratosis and basal cell carcinoma is not fully understood, and it remains controversial whether malignant change occurs in seborrheic keratosis [1, 2, 3]. As in this case, a previous study revealed that, in a majority of cases, basal cell carcinoma was attached to seborrheic keratosis as part of the same tumor, suggesting that the origin of basal cell carcinoma could be seborrheic keratosis [2]. Findings have suggested that it is derived from pluripotent cells of either the epidermis or the hair follicle epithelium [4].
This occult case indicates that there might be more unidentified latent cases in which seborrheic keratosis and basal cell carcinoma coexist, and this condition is relatively more common than expected. Excision rather than laser ablation or cryotherapy might be recommended for treatment, although the significance of such latent lesions remains unclear.
Statement of Ethics
The authors state that the patient gave informed consent to have his case report published.
Disclosure Statement
The authors have no conflicts of interest to declare.
References
- 1.Mikhail GR, Mehregan AH. Basal cell carcinoma in seborrheic keratosis. J Am Acad Dermatol. 1982 Apr;6((4 Pt 1)):500–6. doi: 10.1016/s0190-9622(82)70042-8. [DOI] [PubMed] [Google Scholar]
- 2.Rao BK, Freeman RG, Poulos EG, Arbesfeld L, Rendon M. The relationship between basal cell epithelioma and seborrheic keratosis. A study of 60 cases. J Dermatol Surg Oncol. 1994 Nov;20((11)):761–4. doi: 10.1111/j.1524-4725.1994.tb03201.x. [DOI] [PubMed] [Google Scholar]
- 3.Bedir R, Yurdakul C, Güçer H, Sehitoglu I. Basal cell carcinoma arising within seborrheic keratosis. J Clin Diagn Res. 2014 Jul;8((7)):YD06–07. doi: 10.7860/JCDR/2014/8665.4604. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Akasaka T, Kon S. Two cases of basal cell carcinoma arising in seborrheic keratosis. J Dermatol. 1997 May;24((5)):322–7. doi: 10.1111/j.1346-8138.1997.tb02798.x. [DOI] [PubMed] [Google Scholar]