J Korean Soc Surg Hand.  2016 Sep;21(3):167-172. 10.12790/jkssh.2016.21.3.167.

Epidermoid Cyst after Groin Flap Mimicking Malignancy

• Kang HJ
• Woo YH

• KMID: 2353823
• DOI: http://doi.org/10.12790/jkssh.2016.21.3.167

Abstract

Epidermoid cyst is a benign tumor containing a layer composed by stratified squamous epithelium and filled with keratin. The epidermoid cyst after soft tissue damage such as bite, laceration could be caused by implantation of epidermal cells. There are reports of epidermoid cyst rarely occurred after surgical procedures such as bone graft or spine puncture. However, the report of epidermoid cyst associated with flap in the hand is very rare. We experienced such epidermoid cyst after the groin flap mimicking malignancy in the distal phalanx of the thumb. We found calcified mass with bony erosions in radiologic findings and heterotrophic signals and partial necrosis in magnetic resonance imaging that suggested malignancy. However, it was pathologically diagnosed as an epidermoid cyst. Therefore, we report the case and literature review.

Keyword

Epidermoid cyst; flap

MeSH Terms

Epidermal Cyst*
Epithelium
Groin*
Hand
Lacerations
Magnetic Resonance Imaging
Necrosis
Punctures
Spine
Thumb
Transplants

Figure

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  Fig. 1. The patient had solid, immobile 2×1 cm sized mass that was found in left dorsal tip of thumb.

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  Fig. 2. On radiological finding, soft tissue swelling with calcific material was shown.

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  Fig. 3. (A, B) The computed tomography showed calcification mass with cortical erosion of the dorsal cortex of distal phalanx of thumb.

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  Fig. 4. (A) Fat suppression Image. (B) T1-weighted image, (C) T2-weighted image, (D) gadolinium enhanced Image. On magnetic resonance imaging finding, 23×13 mm sized low signal mass showed segmented horn shape growing from dorsal distal interphalangeal joint to distal area. This mass contained fat tissue on T1, T2 and fat suppression image. In the distal fatty part of mass, heterogeneous enhancement with necrotic change was shown suggesting malignant tumor such as liposarcoma on T1 and gadolinium enhanced image.

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  Fig. 5. (A, B) In the Intraoperative finding, the milk-white color mass was enveloped with a thin membrane with Included calcified tissue without involvement of surrounding tissue.

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  Fig. 6. Microscopic examination of cyst composed with dense keratin (asterisk) with squamous epithelium (arrow). Therefore, it was diagnosed epidermoid cyst (H&E, x100).

Reference

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