Paraspinal ganglioneuroma

Paraspinal ganglioneuromas are extremely rare.

Like neuroblastomas and ganglioneuroblastomas, ganglioneuromas are derived from the primordial neural crest cells that form the sympathetic nervous system.

Ganglioneuromas most commonly arise in the paravertebral sympathetic chains of the posterior mediastinum (41.5%) or retroperitoneum (37.5%). Less common sites include the adrenal gland (21%) and neck (8%) ³. Paravertebral ganglioneuromas frequently extend through the neural foramina to involve the epidural space of the spinal canal ¹¹. Indradural extramedullary ganglioneuromas have been reported but are extremely rare ¹⁰.

Please refer to ganglioneuroma for a more general discussion.

Epidemiology

At the time of diagnosis, 60% of patients are under the age of 20 years ⁷. Median age at diagnosis is 7 years and there is a slight female predominance.

Clinical presentation

Ganglioneuromas are often discovered incidentally becasuse they are grow slowly and are usually endocrinologically inactive ⁹.

Pathology

Ganglioneuromas are benign.

They are fully differentiated tumours composed entirely of ganglion cells and Schwann cells. They do not contain neuroblasts, intermediate cells, or mitotic figures. Necrosis is not a feature ³.

Ganglioneuromas may occur de novo or may arise from maturing neuroblastomas and ganglioneuroblastomas. They may also arise in neuroblastomas and ganglioneuroblastomas that have been treated with chemotherapy ³.

There are rare reports of metastatic ganglioneuromas. It is believed that these tumors represent metastases of neuroblastomas or ganglioneuroblastomas that have subsequently matured to ganglioneuromas. These patients have an excellent prognosis ³.

Radiographic features

Plain radiograph

• may show a posterior mediastinal mass, sometimes causing rib spreading and foraminal erosion
• a retroperitoneal mass may be identified
• scoliosis may be present

CT

• homogeneous low attenuation mass
• calcifications are seen in 42 - 60-60% ³
  • calcification is typically fine and speckled but may be coarse
• slight to moderate enhancement which may be heterogeneous or homogeneous

MRI

Ganglioneuromas are well circumscribed masses. They may appear encapsulated, although a true capsule is infrequent ³.

Signal characteristics include:

• T1: low signal intensity
  • may have a whorled appearance ¹
• T2: heterogenous high signal intensity
• T1 C+ (Gd): enhancement varies from mild to marked

Treatment and prognosis

Typically slow growing.

Treatment consists of complete surgical resection when possible. Complete resection ensures thorough sampling of the tumour, so that a confident diagnosis of ganglioneuroma can be made ³.

Prognosis is usually excellent, however local recurrence has been reported.

Differential diagnosis

• spinal neuroblastoma and ganglioneuroblastoma
  • often cannot be differentiated from ganglioneuroma based on imaging characteristics
  • metastases usually indicate neuroblastoma or ganglioneuroblastoma
  • compared with ganglioneuromas, tumour calcification in neuroblastomas is more often amorphous and of a rough pattern
• spinal schwannoma and neurofibroma
  • centred on neural foramen
  • primarily seen in middle-aged adults