Hansen's Disease presenting as tenosynovitis

Tenosynovitis often occurs in Hansen's Disease (HD) as part of a Type 1 leprosy reaction and rarely as the sole presenting feature of HD. Here, we report a case where the patient presented with tenosynovitis and was later diagnosed as having HD. A 43 year-old fisherman presented with insidious onset of pain in the fingers of the right hand, associated with difficulty in day-to-day fine motor activities. He was diagnosed with tenosynovitis, which was confirmed on ultrasonography. He underwent tenosynovectomy for the same and excess synovial tissue was sent for histopathological analysis; this suggested a diagnosis of granulomatous tenosynovitis indicative of tuberculoid leprosy. On referral to the dermatology department, he was also found to have a thickened right ulnar nerve. On further questioning, he was found to be an old case of Borderline Tuberculoid HD with silent neuropathy of the left ulnar nerve, having completed 12 months of MB-MDT in 2015. At that point, he reported complete recovery of sensations with a negative slit skin smear. In view of the current histopathology report and thickened right ulnar nerve, he was restarted on MB-MDT. Our case is unique as the patient presented with tenosynovitis alone without other features of a leprosy reaction or associated arthritis. This could either have been due to reinfection with M. leprae or due to the presence of persisters. In our country, which is endemic for HD, it is important to keep it as a differential diagnosis for tenosynovitis or arthritis presenting suddenly and failing to respond to conventional lines of therapy, irrespective of the skin lesions or nerve involvement.