Indian Journal of Pathology and Microbiology

: 2015  |  Volume : 58  |  Issue : 4  |  Page : 534--536

Nevus sebaceus with basal cell carcinoma, poroma, and verruca vulgaris

Ali Fuat Cicek1, Andac Aykan2, Abdulkerim Yapici2, Mehmet Gamsizkan3, Serdar Ozturk2, Murat Demiriz1,  
1 Department of Pathology, Gülhane Military Medical Academy, Ankara, Turkey
2 Department of Plastic Surgery, Gülhane Military Medical Academy, Ankara, Turkey
3 Department of Pathology, Maresal Fevzi Cakmak Military Hospital, Erzurum, Turkey

Correspondence Address:
Dr. Ali Fuat Cicek
Gulhane Military Medical Academy, General Tevfik Saglam Street 06018, Etlik, Ankara


Nevus sebaceus (NS) is a congenital, benign, hamartomatous lesion and it is possible to see several benign or malignant tumors accompanying it. One of these is the poroma, which is very rare, and has only been reported twice before, in the English literature. In this paper, we presented two new cases of NS. One of them was a 40-year-old male who presented with a congenital skin lesion on his temporoparietal region. This lesion was composed of four different lesions, including NS, poroma, basal cell carcinoma (BCC), and verruca vulgaris. The second patient was a 41-year-old male presenting with a yellow-brown patch on the scalp. This lesion was comprised of NS and BCC. In addition to these presentations, we discussed the differential diagnosis between BCC and trichoblastoma, both of which are likely to be seen with NS. For this purpose, we recommended an immunohistological panel, which may be useful for differentiating these two morphologically similar lesions.

How to cite this article:
Cicek AF, Aykan A, Yapici A, Gamsizkan M, Ozturk S, Demiriz M. Nevus sebaceus with basal cell carcinoma, poroma, and verruca vulgaris.Indian J Pathol Microbiol 2015;58:534-536

How to cite this URL:
Cicek AF, Aykan A, Yapici A, Gamsizkan M, Ozturk S, Demiriz M. Nevus sebaceus with basal cell carcinoma, poroma, and verruca vulgaris. Indian J Pathol Microbiol [serial online] 2015 [cited 2021 May 15 ];58:534-536
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Full Text


Nevus sebaceus (NS) is a hamartomatous benign skin lesion, which is usually located in the head and neck region.[1],[2] There are numerous publications indicating the possibility of encountering benign or malignant tumors arising from NS in the English literature.[1],[2],[3],[4],[5],[6],[7],[8] In this paper, we reported two new cases of NS. One of them contained a poroma, which has only been reported twice before,[2],[5] with basal cell carcinoma (BCC) and verruca vulgaris. The other one contained BCC. We also touched upon the differentiation between BCC and trichoblastoma (TB), by conducting a brief review of the literature.

 Case Reports

Case 1

A 40-year-old male presented with a painless cutaneous mass on his temporoparietal region [Figure 1]. He stated that the lesion had been present since his birth, but recently, some alterations occurred in its shape and size. He had no remarkable medical or familial history, and there were no abnormalities in his routine biochemical or hematological laboratory results. A total surgical excision was performed, and the removed material was composed of cutaneous and subcutaneous tissue, which was 3.5 cm × 1.9 cm × 0.5 cm in size. There was a cauliflower shaped tumor, 3 cm in diameter, on the skin surface that appeared to be heterogeneous.{Figure 1}

The histological sections revealed four different lesions: (1) NS, (2) verruca vulgaris, (3) eccrine poroma, and (4) BCC. The NS was the dominant lesion, which was located on the surface. Additionally, there were ectopic sebaceous glands directly connected with the skin surface, and immature hair follicles; however, no normal mature follicles were present [Figure 2]a. The second lesion was verruca vulgaris, characterized by an epidermis showing papillomatosis, hyperkeratosis, and acanthosis. The granular layer was prominent [Figure 2]b. Another tumor in the dermis showed continuity with the epidermis, and it was composed of sheets of cells with pale eosinophilic cytoplasm and regular-round nuclei. These findings corresponded to a poroma [Figure 2]c. Finally, the BCC was composed of basaloid cells arranged in a palisade pattern with a retraction artefact, and there was marked pigmentation in the BCC component [Figure 2]d.{Figure 2}

Case 2

The second patient was a 41-year-old male presenting with a yellow-brown patch, which recently changed its appearance, on his scalp. The lesion was removed surgically, and the histological findings were similar to those in the previous case. There was an ondulation on the skin surface due to the prominent papillomatous hyperplasia in the epidermis. Additionally, there were numerous sebaceous glands, which were directly connected with the epidermis [Figure 3]a. In another area, there was an infiltrative tumor connected with the epidermis. The tumor was composed of basaloid cells with peripheral palisading and retraction clefting. These findings corresponded to BCC [Figure 3]b.{Figure 3}

An immunohistochemical study illustrated that the tumor cells forming the BCC were positive for CD10 (DAKO, Mouse Monoclonal, Clone 56C6, 1:80) [Figure 2]e and [Figure 3]c which was positive in the basaloid cells, but not in the stromal cells. The Ki-67 (THERMO, Rabbit Monoclonal, 1:100) proliferation index was high for the basaloid cells [Figure 2]f and [Figure 3]d. No Merkel cells stained with CK20 (BIOGENEX, Mouse Monoclonal, ready-to-use) were detected in either BCC component.


NS is a benign congenital hamartoma presenting as a yellowish plaque on the scalp or face.[2] It is usually asymptomatic at birth, through early adulthood; however, it may show an alteration in its size and shape, probably due to pubertal hormones.[2] In late adulthood, some secondary neoplasms may arise from the lesion. There are many publications indicating that it is possible to see a secondary benign or malignant neoplasm arising from NS.[1],[2],[3],[4],[5],[6],[7],[8] Syringocystadenoma papilliferum and TB (5% and 4.6%, respectively) were found to be the most frequent benign tumors, while BCC was reported as the most frequent malignant one (0.8%), in a wide ranging study.[3]

In a more recent study carried out by Idriss and Elston, among 706 cases, TB was the most frequent benign tumor (n = 52, 7.4%), followed by syringocystadenoma papilliferum (n = 33, 5.2%). Malignant tumors were present in 2.5% of the specimens, with BCC being the most common (n = 8, 1.1%), followed by squamous cell carcinoma (n = 4, 0.57%).[4] Some authors assert that BCC is not common, as far as it is known, because many BCC cases are actually TB. In a study composed of 155 cases of NS, no BCC was present.[5] However, in their study, Baykal et al. found that BCC was the most common neoplasm (40%) in 15 cases with NS.[8] We reviewed two NS cases which contained secondary malignant neoplasms, and both malignant components were BCC.

Here, we made the differential diagnosis between BCC and TB by using morphological and immunohistochemical criteria. Morphologically, both BCC components were composed of basaloid cells showing palisading patterns with peripheral retraction clefting. Some authors claimed that the palisading pattern of basaloid cells may also be seen in TB, but peripheral retraction clefting suggests BCC rather than TB.[2] Furthermore, both tumors (BCC) lacked CK20 positive Merkel cells, which were expected to be present in TB. In a study conducted by Katona et al., 15 trichoepitheliomas (TEs), which are the most common form of TB, and 31 BCCs were studied. All of the TEs (100%) had CK20 (+) Merkel cells, but only 1 of 31 BCCs (3%) had Merkel cells.[6]

In another investigation, Pham et al. studied the CD10 protein immunohistochemically, on paraffin-embedded biopsies of 13 TEs and 23 BCCs. The cases were analyzed for the pattern of CD10 expression by the tumor cells and surrounding stroma. According to their findings, 12 of 13 (92%) TEs showed positive stromal immunoreactivity. Eight of 12 also demonstrated positivity of the papilla, and two showed positivity of the basaloid cells. No TE demonstrated epithelial expression alone; however, CD10 expression in the basaloid cells was identified in 20 (87%) cases of BCC. Stromal positivity was also identified in three cases of BCC. The CD10 stromal positivity around the basaloid nests was statistically significant in TE versus BCC (P < 0.0001), whereas the CD10 epithelial positivity was seen predominantly in BCC (P < 0.0001).[7]

In our study, we encountered similar findings, and found that both BCC components lacked the CK20 positive Merkel cells which were expected to be present in TB. CD10 expression in the basaloid cells was identified in both cases of BCC, whereas no epithelial cells in TB showed CD10 positivity in the control cases.

Poromas are relatively uncommon lesions arising in NS. In the literature, there are only two cases of NS containing poroma which have been reported thus far.[2],[5] In this paper, we reported the third case of NS with poroma. Poromas are often eccrine, involving glabrous sites; however, apocrine poromas are rare, and prone to occur in flexural sites or scalp skin, where apocrine glands can be found. Poromas arising in the NS are likely to be of apocrine origin, given the association of the folliculosebaceous-apocrine unit. Besides the poroma component, this lesion also contains BCC and warts (verruca vulgaris). Warts can be seen in NS, which may show an increased susceptibility to human papillomavirus infections.[5],[8]


It is an expectable condition to see one or more secondary neoplasms arising from NS, but poromas are very rare. In some cases, it is possible to run into a contradiction about the differentiation between BCC and TB, due to their similar morphological features. In such cases, immunohistochemical study showing the CD10 positive basaloid cells, and the paucity of CK20 positive Merkel cells, within the lesion might be helpful to make a diagnosis of BCC rather than TB.

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