Main

Johann Friedrich Horner1 described the syndrome of ptosis, miosis, and anhydrosis as a result of interruption of sympathetic innervation to the eye in 1869. We describe a patient who presented with a preganglionic Horner's syndrome secondary to a malignant peripheral nerve sheath tumour who was subsequently diagnosed as having neurofibromatosis type 1 (NF1). This case highlights the importance of a thorough investigation of any patient presenting with a Horner's syndrome and, to the best of our knowledge, this is the first reported case of NF1 presenting with a Horner's syndrome.

Case report

A 31-year-old woman presented with a 2-month history of a drooping left eyelid. She had no past ocular or medical history. There was a left-sided ptosis and pupil examination revealed an anisocoria that was greater in the dark. These findings were felt to be consistent with a left Horner's syndrome. Lisch nodules were noted bilaterally (Figure 1). Optic discs were healthy bilaterally. Cutaneous examination revealed several small neurofibromas, some café-au-lait spots and axillary freckling. The remainder of the systemic examination was unremarkable and in particular there were no T1 physical signs to suggest a thoracic inlet (Pancoast's) syndrome.

Figure 1
figure 1

Lisch nodules.

Full size image

A computerised tomography (CT) scan of the chest was performed (Figure 2), which showed a nonenhancing dumb-bell-shaped mass extending from the root of the neck anterior to the first rib to approximately 2 cm above the level of the aortic arch. The mass displaced the vessels in the root of the neck anteriorly and abutted the T2 vertebral body posteriorly. A further low attenuation left axillary mass was noted sitting inferolaterally to the left axillary vein and artery. The remainder of the mediastinum was normal and the lung parenchyma were clear.

Figure 2
figure 2

Axial CT scan of the neck showing: (a) left axillary tumour (plexiform neurofibroma); (b) tumour in the root of the neck (MPNST).

Full size image

The patient subsequently underwent exploration and resection of the tumours. The left axillary tumour was found to be a neural tumour in a small branch coming off the infraclavicular brachial plexus. The tumour in the root of the neck was discovered to be two separate tumours: one arising from the T1 nerve root and the other from the sympathetic chain. Histology showed that the axillary tumour was a plexiform neurofibroma and that the two tumours in the root of the neck were both malignant peripheral nerve sheath tumours (MPNST).

The patient was reviewed by the clinical geneticists who diagnosed NF1, on the basis that the three separate neural tumours combined with the cutaneous signs fulfilled the criteria established in 1988.2 There was no previous family history of NF1. The patient made an excellent recovery from the operative procedure and is currently undergoing follow-up by the oncologists.

Comment

Patients with Horner's syndrome may be separated into three groups according to the site of the lesion, these being central, preganglionic, and postganglionic. 3 The preganglionic (second-order) neuron for sympathetic supply to the eye begins in the ciliospinal centre of Budge between the eighth cervical vertebra and the fourth thoracic vertebra (C8–T4) of the spinal cord. The axons exit the spinal cord via the anterior horn, pass through the pulmonary apex and enter the sympathetic chain in the neck, synapsing in the superior cervical ganglion. Although pharmacological testing of the patient's pupils was not performed, the pathology revealed as a result of surgery confirms the Horner's syndrome in this case to be preganglionic in origin. Malignancy has been reported to be the cause of about 25% of cases of preganglionic Horner's syndrome with the most common tumours being lung and breast cancer.4

MPNSTs are defined as soft-tissue tumours of presumed Schwann's cell lineage with anaplastic features in the form of high cellularity, cellular and nuclear pleomorphism, a high mitotic rate, and necrosis. A large number of terms have been applied to such lesions and include malignant schwannoma, malignant neurofibroma, malignant neurilemmoma, neurofibrosarcoma, and neurogenic sarcoma. The incidence of MPNST arising in NF1 is 4.6 and 0.001% in the general population.5 Treatment consists of complete and wide surgical resection. Adjuvant irradiation seems to improve local control of the disease. The prognosis depends on tumour size, history of prior irradiation, surgical excision margin, and the histological presence of necrosis.6 MPNSTs frequently recur locally and metastasize distantly, with the lung being the most common site of metastasis.

In most cases, MPNSTs present late with symptoms of enlarging mass and pain.2, 7 Our patient was fortunate that by presenting with a Horner's syndrome, further investigation resulted in the early diagnosis of MPNST. The subsequent prompt management of the MPNST will hopefully lead to a more favourable outcome in our patient.