Navigating diagnostic complexity: A case of giant cell tumour of tendon sheath of thumb in a patient with prior hypopharyngeal Carcinoma

Giant Cell Tumour (GCT) is a benign neoplasm often found in the tendon sheaths or joints of the hands and feet. Its diagnosis can be challenging due to potential confusion with other benign soft tissue masses or even rare cases of metastasis. In this report, we present a case of a 65-year-old male with a history of post-chemo-radiotherapy-treated carcinoma (CA) of the hypopharynx, who was diagnosed with a Giant Cell Tumour (GCT) of the flexor tendon sheath of the right thumb. Diagnostic confusion initially arose between GCT and fibroma, epidermoid cyst, or acral metastasis due to the multinodular clinical appearance and the patient's history of malignancy. Following comprehensive radiological investigations, the patient underwent excision biopsy. The postoperative period was uneventful, leading to a stable discharge. This report discusses the clinical presentation, diagnostic challenges, course of investigation, diagnosis, and management of the case.