A Rare Case of Trigger Finger Caused by Tumoral Calcinosis in Zone III of the Palm.

Tumoral calcinosis (TC) is a pathological condition characterized by tumor-like calcific deposits in the soft tissues surrounding the joints. This condition typically affects large joints; however, TC involving hand tendons is extremely rare. There are no previously reported cases of TC occurring in Zone III of the palm, and no prior reports of trigger finger secondary to TC. We present a case of TC arising in Zone III of the palmar aspect of the right ring finger in a 65-year-old man who was referred for treatment of trigger finger. Surgical excision of the lesion resulted in symptomatic improvement, and no recurrence was observed seven months postoperatively. This case highlights the potential for atypical Zone III lesions to present as trigger finger and underscores the importance of considering space-occupying lesions in the differential diagnosis. It further emphasizes the need for careful palpation, ultrasonographic evaluation, and radiographic assessment in patients presenting with trigger finger.