What is the differential diagnosis for a lump on the hand?

Differential Diagnosis for a Lump on the Hand

Most Common Etiologies

Ganglion cysts are the most common hand masses, accounting for 50-70% of all hand and wrist lumps, followed by giant cell tumors of the tendon sheath and epidermoid inclusion cysts. 1

Ganglion Cysts

• Present as soft, fluctuant masses typically on the dorsal or volar wrist, but can occur anywhere in the hand 1
• Ultrasound confirms fluid content and is diagnostic in the appropriate clinical setting 2
• Most can be managed nonoperatively with low recurrence rates when surgery is performed 1

Giant Cell Tumor of Tendon Sheath

• Second most common hand mass requiring surgical excision 1
• Notable for higher recurrence rates compared to other benign lesions 1
• Appears as a solid mass on ultrasound with characteristic features 2

Epidermoid Inclusion Cysts

• Common benign lesions typically requiring surgical excision 1
• Often have history of prior trauma or penetrating injury 1

Lipomatous Lesions

Benign Lipomas

• Most common soft-tissue tumor in the body, though giant lipomas (>5 cm) are extremely rare in the hand 3
• Ultrasound is the first-line imaging modality for suspected superficial lipomas, showing characteristic features: hyperechoic or isoechoic appearance, thin curved echogenic lines, minimal vascularity, and no acoustic shadowing 4, 2
• Small (<5 cm), asymptomatic, superficial lipomas with typical ultrasound features require only clinical follow-up 4

Red Flags Requiring Advanced Imaging

• Size >5 cm, deep location, rapid growth, pain/tenderness, or atypical ultrasound features mandate MRI 4
• Deep-seated lipomas or those in the lower limb raise concern for atypical lipomatous tumors (well-differentiated liposarcomas), which require different surgical management 4
• MRI can differentiate benign lipomas from atypical lipomatous tumors in up to 69% of cases 4

Bone-Related Masses

Enchondromas

• Most common bone tumor of the hand 5
• Plain radiographs remain the best initial imaging modality for any suspected musculoskeletal soft-tissue mass, identifying calcification in 27% and bone involvement in 22% of cases 2
• MRI improved grading of hand bone tumors compared to radiography alone, correctly upgrading malignant tumors in 8% and downgrading benign tumors in 12% of cases 2

Heberden and Bouchard Nodes

• Clinical hallmarks of hand osteoarthritis affecting DIPJs and PIPJs respectively 2
• Associated with underlying osteophytes and joint space narrowing on radiographs 2
• Bony enlargement with or without deformity (lateral deviation, subluxation) 2

Vascular and Inflammatory Conditions

Vascular Malformations

• Ultrasound may demonstrate pathognomonic features in arteriovenous malformations 2
• Radiographs can identify phleboliths within hemangiomas 2

Inflammatory/Infectious Masses

• Look for skin changes, warmth, erythema, drainage, or systemic symptoms 6
• Proliferative fasciitis is a rare benign pseudosarcomatous lesion that can present as a painful lump, even causing trigger finger 7

Initial Diagnostic Algorithm

Begin with plain radiographs in two views for any hand mass, as they provide diagnostic information in 62% of cases and can identify calcification, bone involvement, or intrinsic fat 2

When Radiographs Are Diagnostic or Highly Characteristic:

• Phleboliths within hemangioma 2
• Osteocartilaginous masses of synovial chondromatosis 2
• Peripherally mature ossification of myositis ossificans 2

When Radiographs Are Unrewarding:

• Small, deep-seated, non-mineralized masses 2
• Masses in anatomically complex areas like deep soft tissues of the hands 2

Next Step: Ultrasound

Ultrasound has emerged as the preferred initial diagnostic imaging method for soft-tissue masses, with overall sensitivity of 94.1% and specificity of 99.7% for superficial masses 2

• Most useful for superficial lesions above the deep fascia 2
• Highest accuracy for lipomas, followed by vascular malformations, epidermoid cysts, and nerve sheath tumors 2
• Can differentiate solid from cystic lesions and confirm fluid content of ganglion cysts 2
• Diagnostic accuracy is considerably less for deep lesions outside the subcutaneous tissue 2

When to Proceed to MRI:

• Atypical ultrasound or clinical features 2
• Deep-seated or non-superficial masses 2
• Masses in difficult anatomical areas (flank, paraspinal, groin, deep hand/foot) 2
• MRI is the imaging modality of choice for evaluating focal hand lesions, accurately determining nature, enhancement pattern, and exact location 8
• MRI provides superior soft tissue contrast and better evaluates marrow involvement (25%), soft tissue involvement (31%), joint involvement (36.4%), and neurovascular structures (15.3%) compared to CT 2

Critical Pitfalls to Avoid

• Do not rely on MRI alone as the initial examination—radiographs are essential first to identify mineralization, which MRI cannot adequately detect 2
• When ultrasound or clinical features are atypical, further imaging is required even if initial ultrasound appears benign 2
• Most hand tumors are benign, but malignant conditions can mimic benign tumors—advanced imaging should be followed by biopsy before definitive treatment of tumors of unknown diagnosis 5
• Image-guided core needle biopsy is superior to fine needle aspiration for sensitivity, specificity, and histological grading of hand masses 2
• The overwhelming majority (96%) of superficial masses are benign, but pretest probability influences diagnostic accuracy 2

Special Considerations for Malignancy

• While most hand tumors are benign, certain MR features suggest intermediate grade (locally aggressive) or malignant lesions: irregular margins, heterogeneous enhancement, and bony involvement 8
• For any mass with imaging appearances suggestive of soft tissue sarcoma, refer to a specialist sarcoma multidisciplinary team before surgical treatment 2
• Histological examination is usually required for definitive diagnosis despite characteristic MR features 8