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Epidermal Inclusion Cyst

AKA Epidermoid Cyst of Bone

General Considerations Associated with trauma, especially penetrating trauma Usually in bones that are superficially located such as fingers, foot and calvarium Implantation of epithelium that form cysts leading to bone erosion Subungual crush-type injuries have been associated with inclusion cysts as has prior surgery Clinical Findings May develop with in weeks or years of fingertip injury Pain at site of lesion Mass Imaging Findings Frequently seen in terminal phalanx Solitary, lytic lesion May be expansile May have a thin sclerotic border Differential Diagnosis Enchondroma Metastases (rare) Glomus tumor Treatment Surgical curettage Complications May recur if incompletely curetted Prognosis Excellent

Epidermal Inclusion Cyst. White arrows pint to an expansile lytic lesion in the terminal phalanx of the index finger in a characteristic location for an epidermal inclusion cyst of the hand. For these same photos without the arrows, click here and here For more information, click on the link if you see this icon