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E-CORRESPONDENCE |
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| Year : 2013 | Volume
: 58
| Issue : 2 | Page : 164 |
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| A case of desmoplastic trichoepithelioma with ossification |
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Makoto Wada, Keiji Hanada, Fuminao Kanehisa, Jun Asai, Hideya Takenaka, Norito Katoh
Department of Dermatology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto, Japan
| Date of Web Publication | 5-Mar-2013 |
Correspondence Address:
Makoto Wada
Department of Dermatology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto
Japan
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0019-5154.108112
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How to cite this article:
Wada M, Hanada K, Kanehisa F, Asai J, Takenaka H, Katoh N. A case of desmoplastic trichoepithelioma with ossification. Indian J Dermatol 2013;58:164 |
How to cite this URL:
Wada M, Hanada K, Kanehisa F, Asai J, Takenaka H, Katoh N. A case of desmoplastic trichoepithelioma with ossification. Indian J Dermatol [serial online] 2013 [cited 2021 Mar 6];58:164. Available from: https://www.e-ijd.org/text.asp?2013/58/2/164/108112 |
Sir,
Desmoplastic trichoepithelioma was first described as a distinct clinicopathological entity in 1976 by Brownstein and Shapiro. [1] The clinical features of desmoplastic trichoepithelioma are solitary, hard, and annular lesions on the face of a woman. [2] Histologically, desmoplastic trichoepithelioma has three characteristic findings: Narrow strands of basaloid cells, desmoplastic stroma, and keratinous cysts, [3] and is associated with ossification in approximately 6% of cases. [2] We report a case of desmoplastic trichoepithelioma with ossification.
A 30-year-old Finnish man presented to our hospital with an asymptomatic 7 × 5 mm, skin-colored, and slightly-depressed plaque on his left cheek [Figure 1]. He had been aware of the plaque for 2 years, and the lesion had recently increased in size.
Histopathological examination of the lesion revealed small nests of basaloid cells with focal connections to the overlying epidermis [Figure 2]a, keratinous cysts and desmoplastic stroma [Figure 2]b. The basaloid cells were arranged in narrow strands, with one to three rows of cells [Figure 2]c. The stroma consisted of collagen and there were no clefts between the nest of tumor cells and the stroma. Palisading was not observed. At the base of the lesion, a circular bone formation and a foreign-body giant-cell granuloma were present [Figure 2]d. Based on these histological findings, the diagnosis of desmoplastic trichoepithelioma with ossification was made. One month after the skin biopsy, total resection was performed. Histopathological findings of the total resection specimen revealed the same findings as the biopsy. | Figure 1: Clinical features of the patient. A slightly-depressed plaque on his cheek
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 | Figure 2: Histopathological features. (a) Small strands of basaloid cells and a small bone formation were present (H and E, original magnification ×40). (b) Keratinous cyst and desmoplastic stroma (original magnification ×100). (c) The basaloid cells were arranged in narrow strands, with one to three cell thicknesses (original magnification ×100). (d) Adjacent to the bone, a foreign-body giant-cell granuloma was present (original magnification ×100)
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Desmoplastic trichoepithelioma is rare, benign adnexal tumor that usually presents as an asymptomatic, firm, annular plaque, which can closely mimic morpheaform basal cell carcinoma. [4] Brownstein and Shapiro found only three cases of desmoplastic trichoepithelioma with ossification among their series of 50 cases of desmoplastic trichoepithelioma. [2]
The differential diagnosis between desmoplastic trichoepithelioma and morpheaform basal cell carcinoma is important, yet difficult. Histopathologically, desmoplastic trichoepithelioma contain horn cysts, commonly exhibit epidermal hyperplasia, foreign-body keratin granulomas and calcification, all of which are unusual in morpheaform basal cell carcinoma. [2] In contrast, nodular masses of tumor cells with peripheral palisading and abundant mitotic figures, frequently present focally in morpheaform basal cell carcinoma, are absent in desmoplastic trichoepithelioma. [2]
The term osteoma cutis denotes the development of focal ossification in the dermis and the subcutaneous tissue. Ossification can be either primary, arising de novo in healthy skin, or secondary, developing in association with pre-existing neoplastic or inflammatory skin lesions. Secondary osteoma cutis is relatively frequent and is responsible for about 85% of bone found in the skin. [5] Pilomatricomas most commonly undergo ossification. Osteoma cutis frequently occurs in acne scars and is typically found in young women with scarring acne. [6]
The pathophysiologic mechanisms of ossification are unclear. The findings of heterotopic bone formation in acne scars [7] and folliculitis [8] suggest that inflammation of the pilosebaceous unit may play a pivotal role. Some authors believe that inflammation of degenerating keratin pearls results in calcification and subsequent ossification. [9] Other authors have reported that bone-forming cells in secondary ossification may arise from osteogenic stromal elements. [10] It has been reported that in osteoma cutis, fibroblasts may have the ability to differentiate into osteoblastic cells that have properties similar to those of osteoblasts, such as high alkaline phosphatase activity and high expression of osteonectin. [11] Several bone-forming growth-regulating factors that may also participate in secondary ossification have been identified.
In the present case, adjacent to the bone, a keratinous cyst, which is one of the characteristic histopathological findings of desmoplastic trichoepithelioma, and a foreign-body giant-cell granuloma were present. Thus, our findings support the hypothesis that inflammation of degenerating keratin pearls results in calcification and subsequent ossification. [9]
 References | |  |
| 1. | Brownstein MH, Shapiro L. Desmoplastic trichoepithelioma. Arch Dermatol 1976;112:1782. 
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| 2. | Brownstein MH, Shapiro L. Desmoplastic trichoepithelioma. Cancer 1977;40:2979-86.
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| 3. | Gray HR, Helwig EB. Epithelioma adenoides cysticum and solitary trichoepithelioma. Arch Dermatol 1963;87:102-14.
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| 4. | Costache M, Bresch M, Böer A. Desmoplastic trichoepithelioma versus morphoeic basal cell carcinoma: A critical reappraisal of histomorphological and immunohistochemical criteria for differentiation. Histopathology 2008;52:865-76.
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| 5. | Cottoni F, Dell' Orbo C, Quacci D, Tedde G. Primary osteoma cutis. Clinical, morphological, and ultrastructural study. Am J Dermatopathol 1993;15:77-81.
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| 6. | Jewell EW. Osteoma cutis. Arch Dermatol 1971;103:553-5.
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| 7. | Basler RS, Taylor WB, Peacor DR. Postacne osteoma cutis. X-ray diffraction analysis. Arch Dermatol 1974;110:113-4.
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| 8. | Tomsick RS, Menn H. Ossifying basal cell epithelioma. Int J Dermatol 1982;21:218-9.
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| 9. | Delacrétaz J, Christeler A. Ossification phenomena in cutaneous epitheliomas. Dermatologica 1967;134:305-11.
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| 10. | Puzas JE, Miller MD, Rosier RN. Pathologic bone formation. Clin Orthop Relat Res 1989;245:269-81.
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| 11. | Oikarinen A, Tuomi ML, Kallionen M, Sandberg M, Väänänen K. A study of bone formation in osteoma cutis employing biochemical, histochemical and in situ hybridization techniques. Acta Derm Venereol 1992;72:172-4.
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