T1-nerve root neuroma presenting with apical mass and Horner's syndrome

The appearance of dumbbell neuroma of the first thoracic root is extremely rare. The extradural component of a T1-dumbbell neuroma may present as an apical mass. The diagnosis of hand weakness is complex and may be delayed in T1-neuroma because of absence of the palpable cervical mass. One-stage removal of a T1-root neuroma and its intrathoracic extension demanded an extended posterior midline approach in the sitting position.

A 51-year old man had suffered a traumatic partial tendon rupture of his wrist flexor muscles 6 years ago. Since the incident he occasionally felt fullness and tenderness in the affected forearm with some tingling in his fingers bilaterally. During the last two years the hand weakness was continuous and hypotrophy of the medial flexor and intrinsic hand muscles had become apparent. Electrophysiological studies revealed an ulnar neuropathy in addition to mild median and radial nerve dysfunction, including a mild contralateral carpal tunnel syndrome. The diagnostic work-up for multiple mononeuropathy in the upper extremity was negative. Repeated electrophysiological studies revealed fibrillations in the C7 paravertebral muscles on the affected side. Chest x-ray revealed a large round apical mass on the affected side. A Horner's syndrome was noted at this point of diagnostic work-up. MRI of the cervical and thoracic spine revealed a dumbbell T1 neuroma enlarging the intervertebral foramen at T1-2 and a 5 cm large extradural tumor with extension into the apex of the ipsilateral lung. The patient underwent surgery in sitting position using a left dorsal midline approach. Although the T1 root could not be preserved, the patient's neurological condition was unchanged after the surgery.

Extended posterior midline exposure described here using hemilaminectomy, unilateral facetectomy and costo-transversectomy is efficient and safe for one-stage removal of dumbbell tumors at the T1 level with a predominantly extraforaminal component in the apex of the lung extending up to 6-7 cm laterally. Horner's syndrome, if present and observed, may significantly narrow the differential diagnosis of hand weakness caused by T1-root tumors.