Intraosseous Epidermoid Cyst of Distal Phalanx of Fingers

Abstract

Intraosseous epidermoid cysts of fingers are uncommon lesions. We reported two cases with intraosseous epidermoid cysts of distal phalanx of fingers. Case 1 was a 61-year-old woman with a swelling of the left middle finger without history of trauma. Case 2 was a 47-year-old male with a crushing injury of his right thumb. On radiographic findings, a well-circumscribed osteolytic lesion in distal phalanges was noted. Unexpectedly, histological examinations showed intraosseous epidermoid cyst.

Distal Phalanx Intraosseous Epidermoid Cyst

“…The lesion has also been reported in amputation stumps, phalanges of toes, and the big toe; the ulna, femur, tibia, and sternum are some of the other sites of involvement. 8 ( See figure, Supplemental Digital Content 1, which displays the MRI showing intraosseous lesion measuring 1.2 × 1.0 cm. http://links.lww.com/PRSGO/C483 .)…”

“…An epidermoid cyst has a strong edge that is distinct from the poorly defined osteolytic lesions seen with osteolysis. 8 Osteoid osteoma usually presents with a perifocal reactive sclerosis. 9 In poorly defined lytic lesions, several pseudotumorous forms might be recognized (eg, osteomyelitis caused by Staphylococcus as is usually found in diabetic patients).…”

“…7 The lesion has also been reported in amputation stumps, phalanges of toes, and the big toe; the ulna, femur, tibia, and sternum are some of the other sites of involvement. 8 Many theories have been proposed regarding the pathogenesis of intraosseous epidermoid cysts which include congenital, traumatic, and iatrogenic etiologies. However, a traumatic theory remains the most accepted hypothesis.…”

Intraosseous keratin cyst of the distal phalanx

“…Radiologically, the sharp edge of an epidermoid or keratin cyst is distinctly different from the poorly defined osteolytic lesions observed in osteomyelitis and metastatic disease[ 2 ] Histological examination is the only way to confirm the diagnosis. [ 5 ]…”