J Korean Bone Joint Tumor Soc.  2014 Jun;20(1):22-26. 10.5292/jkbjts.2014.20.1.22.

Intraosseous Epidermal Cyst of the Distal Phalanx: A Case Report

• Kong GM
• Kim JY
• Kim JH
• Park DH
• An KH

• KMID: 1707761
• DOI: http://doi.org/10.5292/jkbjts.2014.20.1.22

Abstract

An intraosseous epidermal cyst is a rare benign cystic lesion. It is thought to result from congenital factors or trauma and can lead to bone destruction because the cyst develops at the soft tissue around the bone. Radiological findings of intraosseous epidermal cysts are a well-defined radiolucent lesion, with cortical expansion. It is important to differentiate an intraosseous epidermal cyst with other disease developed at distal phalanx because its clinical and radiological findings are similar. We report two rare cases of intraosseous epidermal cysts that developed at the distal phalanx.

Keyword

intraosseous epidermal cyst; distal phalanx

MeSH Terms

Epidermal Cyst*

Figure

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  Fig. 1. (A, B) Radiographs show a round shaped radiolucent lesion with cortical expansion and thinning of left 2nd finger. (C, D) T1-weighted and T2-weighted MR images show lower and higher signal lesion at the left 2nd distal phalanx.

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  Fig. 2. (A, B) Intraoperatively, the bone cortex was as thin as an egg shell; when the lesion was incised, yellow-tan cheese like creamy material was released, and a thick layer of tissue was peeled from within the cavity of the lesion. Curettage of the lesion was performed. (C, D) Cyst is lined by cornified epithelium, has a distinct granular layer, and contains lamellated keratin without calcification. Although some of these cysts result from traumatic inclusion for the epidermis, the majority probably arise from cystic dilation of the infundibular portion of hair follicles (×100), (×40).

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  Fig. 3. (A, B) Radiographs show a round shaped radiolucent lesion with cortical expansion and thinning of left 4th finger. (C, D) T1-weighted and T2-weighted MR images show lower and higher signal lesion at the left 4th distal phalanx.

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  Fig. 4. (A, B) Anteroposterior and lateral radiographs 14 months after curettage show diminished radiolucent lesion and progression of union compared with previous radiographs. (C) Gross finding shows nail deformity 14 months after operation.

Reference

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