Derm Dx: Mass under the skin of the index finger

Giant cell tumor (GCT) of tendon sheath is the second most common neoplasm of the hand (ganglion cysts are the most prevalent).1 Most are solitary, although a rare variant, referred to as pigmented villonodular synovitis, presents with multiple lesions, usually...

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Giant cell tumor (GCT) of tendon sheath is the second most common neoplasm of the hand (ganglion cysts are the most prevalent).¹ Most are solitary, although a rare variant, referred to as pigmented villonodular synovitis, presents with multiple lesions, usually on the lower extremities.² 

The etiology of GCTs is uncertain; some believe that the condition represents a reactive process secondary to underlying inflammation, possibly induced by trauma or infection.³ GCT primarily affects individuals aged 30 to 50 years, with a slight female predilection. Many cases are associated with osteoarthritis.

GCT presents as a solid, nontender, flesh-colored nodule firmly fixed to underlying tissue. As the majority are asymptomatic, treatment is often deferred, and some are tolerated for decades.

Radiologic imaging may demonstrate bone erosion, and magnetic resonance imaging reveals areas of low signal density.⁴ Histology shows sheets of rounded or polygonal cells with variable numbers of giant and xanthoma cells.

Treatment of GCTs entails surgical removal, which is often difficult because of the depth of the lesion and its fixation to underlying tissue. Recurrence is not uncommon and may be as high as 27%.⁵

Megha D. Patel is a student at the Commonwealth Medical College, Scranton, Pennsylvania.

Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College and an adjunct assistant professor of dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, Pennsylvania.

References

1. Di Grazia S, Succi G, Fragetta F, Perrotta RE. Giant cell tumor of tendon sheath: study of 64 cases and review of literature. G Chir. 2013;34(5-6):149-152.
2. Murphey MD, Rhee JH, Lewis RB, Fanburg-Smith JC, Flemming DJ, Walker EA. Pigmented villonodular synovitis: radiologic-pathologic correlation. Radiographics. 2008;28(5):1493-1518.
3. Hosaka M, Hatori M, Smith R, Kokubun S. Giant cell formation through fusion of cells derived from a human giant cell tumor of tendon sheath. J Orthop Sci. 2004;9(6):581-584.
4. Jelinek JS, Kransdorf MJ, Shmookler BM, Aboulafia AA, Malawer MM. Giant cell tumor of the tendon sheath: MR findings in nine cases. AJR Am J Roentgenol. 1994;162(4):919-922.
5. Reilly KE, Stern PJ, Dale JA. Recurrent giant cell tumors of the tendon sheath. J Hand Surg Am. 1999;24(6):1298-1302.