Neurogenic Thoracic Outlet Syndrome: A Rare Differential Diagnosis of upper Extremity Paresthesia in a Pediatric Patient

Aims: Thoracic outlet syndrome (TOS) consists of a variety of symptoms related to neurovascular compression at the upper thoracic outlet. Various etiologies, related to bony or soft tissue anomalies, have been associated with TOS. The incidence of TOS is 0.3 to 2% in adult population, with a female predominance and debut between the 2nd and 4th decade of life. It is rarely diagnosed in children. There are only a few case reports of pediatric TOS published in the literature, mainly due to cervical ribs.

Methods: This study is a case report and the literature review.

Results: A 14-year-old girl presented with intermittent paresthesia of the palmar side of the right arm, duration 8 to 10 minutes, 3 times/month, and no provoking factors. Physical status and neurological status were normal, except a slightly diminished superficial sensibility in right forearm. Brain/neck MRI, EEG, EMG, and ENG were normal. We decided to observe the patient with follow-up visits every 6 months. The clinical course was stable > 1 year with episodes being less frequent. However, the patient began to notice provocation of paresthesia by “carrying a bunch of hot baguettes.” The clinical significance of this observation remained unclear at this time. A somatic symptom disorder was considered as possible, but questionable differential diagnosis, as patient and family denied emotional stress or anxiety. At follow-up at the age of 16 years, paresthesia of right arm was observed 1/week lifting weights with the arms in a gym. EMG/ENG were repeated and revealed postganglionic involvement of lower trunk of brachial plexus with mild sensory and motor axonal degeneration. MRI and CT of brachial plexus were performed, demonstrating elongation of the C7 transverse process.

Conclusion: Symptoms with mega-apophysis are uncommon, but rapid growth in adolescence can precipitate TOS as the anatomy of the thoracic aperture is changing. Because of the variety of clinical symptoms and underlying etiology, the diagnosis of TOS remains a challenge. The condition can be easily missed, especially in the pediatric population where TOS is less likely to be considered.

Keywords: thoracic outlet syndrome, childhood, elongation of the C7 transverse process.