Higher incidence rates than previously known in tenosynovial giant cell tumors

Abstract

Background and purpose - Tenosynovial giant cell tumors (TGCT) are rare, benign tumors, arising in synovial lining of joints, tendon sheaths, or bursae. 2 types are distinguished: localized, either digits or extremity, and diffuse lesions. Current TGCT incidence is based on 1 single US-county study in 1980, with an incidence of 9 and 2 per million person-years in localized (including digits) and diffuse TGCT, respectively. We aim to determine nationwide and worldwide incidence rates (IR) in TGCT affecting digits, localized-extremity TGCT and diffuse-type TGCT. Material and methods - Over a 5-year period, the Dutch Pathology Registry (PALGA) identified 4,503 pathology reports on TGCT. Reports affecting digits were solely used for IR calculations. Reports affecting extremities were clinically evaluated. Dutch IRs were converted to world population IRs. Results - 2,815 (68%) digits, 933 (23%) localized-extremity and 390 (9%) diffuse-type TGCT were identified. Dutch IR in digits, localized-extremity, and diffuse-type TGCT was 34, 11 and 5 per million person-years, respectively. All 3 groups showed a female predilection and highest number of new cases in age category 40-59 years. The knee joint was most often affected: localized-extremity (46%) and diffuse-type (64%) TGCT, mostly treated with open resection: localized (65%) and diffuse (49%). Reoperation rate due to local recurrence for localized-extremity was 9%, and diffuse TGCT 23%. Interpretation - This first nationwide study and detailed analyses of IRs in TGCT estimated a worldwide IR in digits, localized-extremity and diffuse TGCT of 29, 10, and 4 per million person-years, respectively. Recurrence rate in diffuse type is 2.6 times higher, compared with localized extremity. TGCT is still considered a rare disease; however, it is more common than previously understood.

Figure 1.

MRI of localized-type TGCT, affecting digits: a 43-year-old male patient with a well-circumscribed tumor in the proximal phalanx of the third digit of the right hand. Left panel: A coronal T1-weighted MRI after intravenous contrast injection. Right panel: A clear coronal T1-weighted MRI without intravenous contrast injection.

Figure 2.

MRI of TGCT localized-type, extremity: sagittal T1-weighted turbo spin echo MRI of a 47-year-old female patient, affecting her right knee. A well-circumscribed lesion in Hoffa’s fat pad is seen. Left panel: Proton density weighted MRI. Right panel: Pre-saturation inversion recovery MRI.

Figure 3.

MRI of diffuse-type TGCT: a 23-year-old male patient with an extensive proliferative synovial process around both cruciate ligaments, dominating the anterior and posterior knee compartments, intra- and extra-articular. Inside suprapatellar pouch and Baker’s cyst a blooming villonodular aspect shows typical iron depositions. Left panel: Sagittal proton density weighted turbo spin echo MRI. Right panel: Sagittal T2-weighted fast field echo MRI.

Figure 4.

Inclusion flowchart. ^a Localized TGCT affecting extremities, excluding digits.

Figure 5.

Skeleton, showing affected TGCT localization (fingers and toes excluded). 3% in localized type and 1% in diffuse type is classified as “other”.

Figure 6.

Initial treatment for TGCT affecting extremities in The Netherlands, excluding digits.

Figure 7.

Reoperation due to local-recurrence-free survival curve in localized-extremity and diffuse TGCT (Kaplan–Meier), excluding digits. Time zero is time of primary surgery. 8 patients died and were censored at time of death if a recurrence had not occurred.