Glomus tumor of digital nerve - a case report.

Abstract

Dear Sir 32 year old lady was seen for pain in ulnar border of ring finger of 3 years duration. Examination revealed point tenderness and a pea-sized nodule over the ulnar border of the ring finger approximately 1 cm distal to the DIP joint crease. Tapping over the swelling produced parasthesiae. Hematological investigations and plain radiographs were normal. MRI showed lesion arising from the terminal branch of the ulnar digital nerve (Fig. 1). The patient underwent exploration under regional anasthesia and loupe magnification. Intra-operatively, a 0.5 cm × 0.5 cm swelling which was greyish blue was seen arising from the terminal branch of the digital nerve (Fig. 2). It was possible to separate this swelling from the nerve branch. Histopathological examination was suggestive of Glomus tumor. The patient was disease free at the end of 1 year follow-up. Fig. 1 MRI showing swelling in the Ulnar digital nerve of the middle finger Fig. 2 Intraoperative picture showing the tumor arising from the terminal digital nerve Glomus tumor arising from digital nerve is rare as human nerve does not contain glomus bodies. Only three cases have been reported in the literature Mitchell et al. [1]. Mitchell et al. [1] and Kline et al. [2] described glomus tumors arising from the ulnar digital nerve of the thumb. Kim and Jung [3] described similar lesion in ulnar digital nerve of ring finger in the 4th web. All lesions were successfully treated by surgery. Other tumors of digital nerve like Schwanomma [4] have been reported. Differential diagnosis considered in our patient were benign nerve tumors, GCT of tendon sheath and implantation dermoid. The presence of parasthesiae on tapping was more suggestive of nerve tumor. The patient had multiple consultations and treatments before she was seen by us. Excision resulted in complete resolution of symptoms although she had a tender scar for about 3 months post-operatively. This case emphasizes the fact that although glomus tumors are typically sub-ungual, they can also occur in other unusual places like the one described. Biopsy followed by immunohistochemistry analysis would confirm the neural origin. An index of suspicion is necessary to prevent delay in diagnosis.