Digital mixoid cyst

Background

• Also known as digital mucous cyst or mixoid pseudocyst
• Benign collection of gelatinous material, from degeneration of connective tissue
• Typically affects DIP joint, with swelling over distal phalanx

Clinical Features

Digital mucous cyst in left index finger with nail depression

• Swelling to distal finger, usually radial aspect +/- pain
• Aspiration yields clear, gelatinous fluid
• May communicate with joint space

Differential Diagnosis

Hand and finger infections

• Bed bugs
• Closed fist infection (Fight Bite)
• Hand cellulitis
• Hand deep space infection
• Hand-foot-and-mouth disease
• Herpetic whitlow
• Felon
• Flexor tenosynovitis
• Paronychia
• Scabies
• Sporotrichosis

Look-Alikes

• Digital mixoid cyst

Evaluation

• Firm nodule to distal finger or toe
• May cause longitudinal depressed groove in nail plate

Workup

• XR of digit may be useful to show joint degeneration, but not required

Management

• Aspiration (25g needle) or I&D
• Digital compression
• May require surgical excision if recurring

Disposition

• Discharge

External Links

• https://www.aocd.org/page/DigitalMucousCyst