DERMATOLOGICA SINICA xxx (2017) 1e2
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Epithelioid fibrous papule: A rare variant mimicking desmoplastic Spitz nevus Dear Editor, Fibrous papule (FP) is a common benign lesion most frequently seen on the nose or central face of middle-aged adults. Several variants of FPs have been documented, including hypercellular, clear cell, granular cell, inflammatory, pigmented, and pleomorphic type.1e3 Epithelioid fibrous papule is a rare variant of FP and was only reported by Kucher et al. in 2007.1 Herein, we report another case of epithelioid FP of the nose with a unique histopathological pattern. A 26-year-old female patient visited our outpatient department with a 3-year history of a slowly growing papule over the nose tip (Fig. 1). Physical examination revealed a solitary asymptomatic skin-colored papule, measuring 3 mm in diameter. An excisional biopsy was taken from the lesion site. Histopathologic examination showed a well-demarcated dome-shaped papule with increased numbers of large cells (Fig. 2A). These large cells are characterized by centrally located to eccentric nuclei and abundant pale eosinophilic cytoplasm, and some by delicate nucleoli (Fig. 2B). There are also dilated vessels on the superficial dermis and sclerotic stroma. No Touton giant cells were seen in the specimen. On routine hematoxylin and eosin staining, the histopathologic finding was very similar to desmoplastic Spitz nevus. Further immunohistochemical staining results with S-100, CD-10, CD-68, NKI/C3, and pan-CK were all negative. Factor XIIIa was seen in several dendritic cells located in the papillary dermis. According to the clinical and histopathologic findings, we made the diagnosis of epithelioid fibrous papule. Epithelioid fibrous papule, a rarely reported variant of FP, was only reviewed once by Kucher et al. in the English literature.1 In their study, they collected 10 cases of epithelioid FP and 14 cases of other FP variants. In the group of the epithelioid type, seven cases were male and the group age ranged from 32 to 68 years. Most of the biopsies were taken from the nose, except one from the cheek and one from the lower eyelid, respectively. Clinically, the epithelioid FP cannot be differentiated from other FP variants. Histologically, it featured epithelioid cells with ample pale cytoplasm, variably sized nuclei, and small but obvious nucleoli. The epithelioid cells in their cases are often grouped and nested reminiscent of a melanocytic tumor. Interestingly, the epithelioid foci can also be seen in the hypercellular variant. Immunohistochemical staining with S-100 and NKI/C3 were negative in all cases; CD-68 was scattered positive in 10 cases (70%); Factor XIIIa showed positivity in several dendritic cells in 5 cases (50%), but negative in epithelioid cells; procollagen was diffusely positive in all cases.
In our case, the specimen was taken from the nasal tip of a 26year-old female patient. Histologically, it shared the similarity with Kucher's cases, except that the epithelioid cells in our case lacked the nested pattern, but mingled discretely in the sclerotic stroma, mimicking desmoplastic Spitz nevus. This is a unique feature in our case. There are no specific immunochemical stains for epithelioid FP. The diagnosis mainly relies on its unique histological feature. The pathogenesis of FP has been in debate with several explanations including an involuting melanocytic nevus,4 a perifollicular fibroma,5 and a fibrotic response to inflammation.6 However, subsequent electron microscopic studies and the immunohistochemical staining showed the constituent of FP to be more likely of fibroblastic origin rather than of melanocytic differentiation.7,8 The differential diagnosis of the epithelioid FP includes epithelioid fibrous histiocytoma, Spitz nevus, xanthogranuloma, and cellular neurothekeoma. Epithelioid fibrous histiocytoma has a predilection for extremities and is rarely seen on the face. Histologically, it is featured by sheets of angulated epithelioid cells with abundant eosinophilic cytoplasm with many small blood vessels,
Fig. 1 One asymptomatic skin-colored papule over nasal tip.
http://dx.doi.org/10.1016/j.dsi.2017.07.002 1027-8117/Copyright © 2017, Taiwanese Dermatological Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Chen Y-H, et al. Epithelioid fibrous papule: A rare variant mimicking desmoplastic Spitz nevus, Dermatologica Sinica (2017), http://dx.doi.org/10.1016/j.dsi.2017.07.002
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Correspondence / Dermatologica Sinica xxx (2017) 1e2
Fig. 2 Histological features of the lesion. (A) A dome-shaped papule (hematoxylin and eosin stain; magnification: 20). (B) Background sclerotic stroma interspersed with epithelioid cells and ectatic vessels. The epithelioid cells show pale eosinophilic cytoplasm and prominent nuclei, some with obvious nucleoli (hematoxylin and eosin stain; magnification: 100). The inset figure shows the high magnification view of the epithelioid cells (hematoxylin and eosin stain; magnification: 400).
but not sclerotic stroma as in epithelioid FP. The epithelioid cells are typically positive for fibrohistiocytic markers including CD10, CD68, and factor XIIIa. Spitz nevus, as we mentioned before, may resemble, to some extent, to epithelioid FP, but the cells show strong positive staining with S-100. While xanthogranuloma and FP are both common facial lesions, xanthogranuloma contains foamy cells, scattered Touton giant cells, and, occasionally eosinophils and lymphocytes. Cellular neurothekeoma has more cellular, nested proliferation of epithelioid to spindled cells with fibrous septa, which is very different from the architecture of epithelioid FP under the microscope. In conclusion, the epithelioid cell type is a rare variant of FP. When encountering a specimen very similar to desmoplastic Spitz nevus on hematoxylin and eosin staining, epithelioid FP should be considered. Dermatologists should be cautious of this entity to avoid misdiagnosis and overtreatment, considering the commonality of FPs. Conflict of interest The authors declare no conflicts of interest. Yi-Hsien Chen
Hong-Wei Gao Department of Pathology, Tri-Service General Hospital, Taipei, Taiwan
Bai-Yao Wu* Department of Dermatology, Tri-Service General Hospital, Taipei, Taiwan *
Corresponding author. Department of Dermatology, Tri-Service General Hospital, No. 325, Sec. 2, Chenggong Rd., Neihu Dist., Taipei City 114, Taiwan. Fax: þ886 2 8792 7181. E-mail address:
[email protected] (B.-Y. Wu).
References 1. Kucher C, McNiff JM. Epithelioid fibrous papule e a new variant. J Cutan Pathol 2007;34:571e5. 2. Guitart J, Bergfeld WF, Tuthill RJ. Fibrous papule of the nose with granular cells: two cases. J Cutan Pathol 1991;18:284e7. 3. Bansal C, Stewart D, Li A, Cockerell CJ. Histologic variants of fibrous papule. J Cutan Pathol 2005;32:424e8. 4. Meigel WN, Ackerman AB. Fibrous papule of the face. Am J Dermatopathol 1979;1:329e40. 5. Zackheim HS, Pinkus H. Perifollicular fibromas. Arch Dermatol 1960;82:913e7. 6. Rosen LB, Suster S. Fibrous papules. A light microscopic and immunohistochemical study. Am J Dermatopathol 1988;10:109e15. 7. Ragaz A, Berezowsky V. Fibrous papule of the face. A study of five cases by electron microscopy. Am J Dermatopathol 1979;1:353e6. 8. Cerio R, Rao BK, Spaull J, Jones EW. An immunohistochemical study of fibrous papule of the nose: 25 cases. J Cutan Pathol 1989;16:194e8.
Department of Dermatology, Tri-Service General Hospital, Taipei, Taiwan
Wei-Ming Wang Department of Dermatology, Tri-Service General Hospital, Taipei, Taiwan Department of Medicine, National Defense Medical Center, Taipei, Taiwan
Received: Apr 19, 2017 Revised: Jun 20, 2017 Accepted: Jul 15, 2017
Please cite this article in press as: Chen Y-H, et al. Epithelioid fibrous papule: A rare variant mimicking desmoplastic Spitz nevus, Dermatologica Sinica (2017), http://dx.doi.org/10.1016/j.dsi.2017.07.002
