Abstract
Localized tenosynovial giant cell tumor (lTGCT), formerly termed giant cell tumor of the tendon sheath (GCTTS), is a benign soft tissue neoplasm that commonly affects the hand and wrist, with rare involvement of the foot and toes. We report a case of localized TGCT involving the right second toe in a 22-year-old male with type 2 diabetes mellitus and prior renal transplantation requiring chronic immunosuppressive therapy. The lesion had been present for several years with recent progression in size. Clinical and ultrasonographic findings were suggestive of a benign superficial soft tissue mass, and complete surgical excision was performed. Histopathological examination confirmed localized-type TGCT. This case is notable for the occurrence of lTGCT in a young solid-organ transplant recipient on chronic immunosuppression, a clinical context with a paucity of reported cases. Although the patient’s medical history did not alter the standard surgical management of this localized lesion, it broadened the differential diagnosis and underscores the importance of histopathological confirmation in immunocompromised patients to exclude malignant mimics, post-transplant lymphoproliferative disease, and atypical infections.
Introduction
Localized tenosynovial giant cell tumor (lTGCT), historically termed giant cell tumor of the tendon sheath (GCTTS), is now classified within the broader spectrum of tenosynovial giant cell tumors (TGCTs), a group of benign proliferative lesions arising from synovium, tendon sheaths, joints, or bursae. This nomenclature reflects the World Health Organization classification shift that groups formerly separate entities, including localized nodular tenosynovitis and pigmented villonodular synovitis, under the TGCT spectrum. , lTGCT is among the most common benign soft tissue tumors of tendon sheath origin in the hand and wrist, whereas involvement of the foot and toes is uncommon, accounting for a minority of reported cases. ,
TGCTs are categorized into localized and diffuse forms. The localized type, as presented in this case, typically manifests as a discrete, slow-growing, firm, and often painless mass. This indolent nature may lead to a significant delay between symptom onset and clinical presentation. Despite its benign histology, lTGCT may cause mechanical symptoms, functional limitation, or compression of adjacent structures. Definitive diagnosis is established by histopathological examination, and complete surgical excision is the standard of care, with the goal of removing the lesion while preserving tendon and neurovascular function.
Although lTGCT of the foot and ankle has been described in case reports, retrospective series, and systematic reviews, reports involving solid-organ transplant recipients receiving chronic immunosuppression appear exceedingly rare. , This case is notable for its occurrence in a young diabetic renal transplant recipient on chronic immunosuppressive therapy—a clinical context that broadens the differential diagnosis and underscores the importance of histopathological confirmation, as such patients are at elevated risk for atypical infections and post-transplant malignancies that may mimic benign soft tissue tumors. ,
Case Presentation
Patient Information
A 22-year-old male presented to the diabetic foot clinic for evaluation of a persistent soft tissue mass on the plantar aspect of his right second toe. The patient first noted the lesion in 2018, and it had remained stable and asymptomatic for several years. However, over the eight months preceding presentation, he observed a progressive increase in its size. He denied any history of trauma to the area, associated pain, discharge, or constitutional symptoms such as fever or weight loss.
His past medical history was significant for end-stage renal disease secondary to posterior urethral valve and neurogenic bladder, status post living-related kidney transplant on May 14, 2017 with stable graft function, type 2 diabetes mellitus diagnosed in October 2021, a seizure disorder with no seizures for over one year and no current antiepileptic therapy, bilateral genu valgum, and obesity with a body mass index of 33 kg/m². His long-term medications included immunosuppressants (tacrolimus, mycophenolate mofetil, and prednisone) and medications for comorbidities (amlodipine, losartan, metformin, labetalol, magnesium oxide, and sodium bicarbonate).
Clinical Findings
On physical examination, a firm, non-tender, subcutaneous mass was palpated on the plantar aspect of the right second toe, proximal to the distal interphalangeal joint. The mass was mobile relative to the underlying flexor tendon but appeared fixed to deeper soft tissues. The overlying skin was intact, with no erythema, ulceration, or signs of infection. The neurovascular status of the toe was preserved, with brisk capillary refill and intact sensation to light touch.
Diagnostic Assessment
Anteroposterior radiograph of the right foot was obtained, which revealed no evidence of calcifications, cystic changes, or bone erosion associated with the soft tissue mass ( Figs. 1-6 ) .
Clinical photographs showing the location of the mass on the right second toe.
Anteroposterior radiograph of the right foot showing normal osseous structures with no evidence of erosion or calcification.
Grayscale and color Doppler ultrasound images demonstrating a well-defined, hypoechoic, heterogeneous soft tissue mass with mild internal vascularity.
Intraoperative photograph showing the encapsulated tumor.
Immediate postoperative appearance of the right second toe after wound closure.
Clinical appearance of the right second toe at the Seven-month postoperative follow-up, showing a well-healed incision.
An ultrasound examination of the right foot was performed to further characterize the mass. It revealed a well-defined, solid, hypoechoic, and heterogeneous soft tissue mass on the plantar aspect of the second toe, measuring approximately 2.0 × 1.2 × 0.65 cm. Color Doppler imaging demonstrated mild internal vascularity. The mass was noted to be in close proximity to the underlying flexor tendon sheath.
Ultrasound was selected as the initial imaging modality given its ready availability, low cost, lack of ionizing radiation, and utility in characterizing superficial soft tissue masses of the digits. In the setting of a small, superficial, palpable mass of the toe without clinical concern for deep extension or bone involvement, ultrasound provided adequate initial characterization. MRI, which is considered the gold standard for definitive characterization of soft tissue tumors including lTGCT, would be considered in cases with atypical imaging features, suspected deeper invasion, bone involvement, or diagnostic ambiguity warranting further pre-operative planning.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
