Dermatology Online Journal

Fibroepithelioma of Pinkus with pleomorphic epithelial giant cells
Susan K Repertinger¹, Todd Stevens¹, Nicholas Markin², Heather Klepacz², Deba P Sarma¹
Dermatology Online Journal 14 (12): 13

1. Department of Pathology, Creighton University Medical Center, Omaha, Nebraska, US. debasarma@creighton.edu
2. Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska, US

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Abstract

Fibroepithelioma of Pinkus is a rare, indolent variant of basal cell carcinoma (BCC). The presence of pleomorphic giant cells in such a tumor is extremely rare and to our knowledge, only one such case has been previously reported in the literature. We report another case occurring as a pedunculated, gluteal lesion in an 82-year-old man. The nodule was lightly pigmented, polypoid, and measured 1.0 cm in greatest dimension. Immunohistochemical staining confirmed that the giant cells were of epithelial origin and that the proliferative rate of these cells was low.

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Clinical Synopsis

An 82-year-old man with a history of multiple subcutaneous lipomas presented with a 1.0 cm, pedunculated, left gluteal nodule, which had been bothering him for an unknown period of time. On physical examination, the tumor was lightly pigmented, ovoid, and showed signs of irritation. The tumor was excised at its base.

Figure 1	Figure 2
Figure 1. Fibroepithelioma of Pinkus, low magnification Figure 2. Higher magnification showing giant cells

Figure 3
Figure 3. Pleomorphic multinucleated giant cells

Microscopic examination of the resected tissue showed the characteristic features of fibroepithelioma of Pinkus, with anastomosing, reticular cords of basaloid cells connecting to the overlying epidermis. The intervening stroma was loose and abundant, with minimal inflammation (Fig. 1). Within the anastomosing cords were multinucleated, pleomorphic giant cells arranged singly and in small clusters. Most of the nuclei were hyperchromatic; some had prominent indentations and clefts. The giant cell nuclei were 2-3 times the diameter of adjacent mononuclear tumor cells (Figs. 2 & 3). Immunohistochemical staining for p63 (Fig. 4), CD68 (Fig. 5), and pancytokeratin confirmed the nature of the giant cells to be of basal cell and not histiocytic origin. The proliferative index by Ki-67 staining was minimal at <1 percent. The proliferative index within the mononuclear basal cells was approximately 5 percent. A few mitoses were seen.

Figure 4	Figure 5
Figure 4. The neoplastic epithelial cells and the giant cells show strongly positive p63 nuclear stain suggesting the basal cell nature of the cells. Figure 5. Giant cells are negative for CD68 suggesting that they are not of histiocytic origin.

Discussion

Fibroepithelioma of Pinkus is a well-known, but uncommon, variant of basal cell carcinoma. The presence of tumor giant cells within these tumors is very rare. To our knowledge, it has only been reported once in the English literature [1]. This is in contrast to pleomorphic basal cell carcinoma, which is well-described [2, 3]. Val-Bernal et al. reported a case of fibroepithelioma of Pinkus with giant cells in 2002. The tumor was also described as a polypoid, pedunculated nodule, but occurred in the axilla of an 86-year-old woman [1]. Similar to our case, the tumor giant cells were described as containing hyperchromatic, pleomorphic nuclei that were much larger than the surrounding mononuclear tumor cells. Likewise, the proliferative rate by Ki-67 immunohistochemical staining was 1 percent in tumor giant cells and 4 percent in the surrounding mononuclear tumor cells. The tumor cells, including the tumor giant cells, showed negativity for bcl-2, p53, alpha-smooth muscle actin, BerEP4, CD34, and S-100 protein; thus, some of the common immunohistochemical markers typical of BCC were negative and p53 was not expressed in the giant cells. The authors also performed morphometric analysis on the case. This showed the giant cells to have a mean nuclear major diameter that was more than twice the mean nuclear major diameter of the mononuclear cells. DNA flow cytometric analysis showed the tumor to be aneuploid; the S-phase fraction of the aneuploid population (18.10%) was intermediate in grade.

Fibroepithelioma of Pinkus is an indolent variant of BCC, described by Pinkus in 1953 as "pre-malignant" [4]. It is of interest that both patients presenting with this type of tumor containing giant cells were elderly people in their 80s. A low proliferative index suggests that the giant cells do not adversely affect prognosis and that the presence of such cells may be a degenerative phenomenon, as suggested previously. The importance of recognizing this variant lies in not attributing to it a more aggressive clinical course.

References

1. Val-Bernal JF, Gomez-Ortega JM, Fernandez-Llaca H, Gomez-Roman JJ. Fibroepithelioma of Pinkus with tumor giant cells. Am J Dermatopathol 2002; 24(4): 336-339. [PubMed]

2. Okun, MR. Pleomorphic giant cells in basal cell carcinoma. J Cutan Pathol 2000; 27(2): 99. [PubMed]

3. Meehan, SA, Egbert BM, Rouse RV. Basal cell carcinoma with tumor epithelial and stromal giant cells: a variant of pleomorphic basal cell carcinoma. Am J Dermatopathol 1999; 21(5): 473-478. [PubMed]

4. Pinkus H. Premalignant fibroepithelial tumors of skin. AMA Arch Derm Syphilol 1953; 67(6): 598-615. [PubMed]

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