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We describe a peripheral primitive neuroectodermal tumour (PPNET) arising from the cervical paravertebral region of a 34 year old woman, who presented with Horner’s syndrome and a cervical radiculopathy. PPNETs are rare malignant small round cell tumours. This appears to be the first documented case of localised PPNET with Horner’s syndrome at initial presentation.
A 34 year old woman presented with acute left scapula pain, numbness of her left forearm, a left upper lid ptosis, and left hemifacial anhydrosis. Her symptoms disappeared spontaneously within a fortnight, but returned 2 months later with greater intensity. Examination then revealed wasting of the small muscles of her left hand with reduced power in the distribution of C8 and T1; there was loss of light touch and pinprick in the C8 dermatome. The presence of left 1 mm upper lid ptosis, miosis, hemifacial anhydrosis, and 1 mm lower lid (“upside down”) ptosis was highly suggestive of a preganglionic left Horner’s syndrome (Fig 1A). Magnetic resonance imaging (MRI) of the neck showed a large mass arising from the T1, T2 intervertebral foramen extending into the root of the left side of the neck and the region of the apex of the left lung (Fig 1B).
A diagnostic biopsy was performed through a posterolateral approach, excising the extradural component of the tumour within the nerve root canal. Histology revealed a malignant round cell tumour consistent with a peripheral primitive neuroectodermal tumour (PPNET, Fig 2). Immunohistochemical studies demonstrated positivity for focal vimentin, cytokeratins, synaptophysin, and MIC-2, but were negative for GFAP (glial fibrillary acidic protein), S100, desmin, and the lymphoid markers LCA, CD3, and CD20. Staging investigations showed no evidence of metastatic disease and therefore the diagnosis of localised PPNET was made.
The patient received chemotherapy as primary treatment followed by radiotherapy and has been in remission since. A year later she was referred to our unit for correction of her left ptosis, and underwent left anterior levator resection with a satisfactory result. Four years following her initial diagnosis she remains free of recurrent disease.
Horner’s syndrome is caused by an oculosympathetic deficit to the pupillodilator and superior and inferior tarsal retractor muscles.1–3 It is manifest by upper lid ptosis, ipsilateral miosis, apparent enophthalmos due to lower lid (“upside down”) ptosis, and often facial anhydrosis.4 The presence of all these features in our patient, together with the left facial anhydrosis, was indicative of a preganglionic lesion, since the sympathetic facial sweat fibres branch distal to the superior cervical sympathetic ganglion and central neurological tract signs were absent.2,3 Preganglionic Horner’s syndrome is frequently associated with neoplasms of the pulmonary apex, mediastinum, or neck, as illustrated by the location of the PPNET seen in our patient (Fig 1B).
PPNET is a rare malignant small round cell tumour that can affect any age group but is thought to peak in adolescence, with no sex predilection.5 The most common location is the thoracopulmonary region, followed by the head and neck. Extraosseous Ewing’s sarcoma is now considered a form of PNET, through immunohistochemical, ultrastructural, and histogenetical similarities.6 Both tumours express elevated levels of glycoprotein p30–32, a product of the MIC-2 gene, in a unique and highly selected fashion, as well as specific translocations involving a gene on chromosome 22q12. Indeed, the tumour cells of our patient exhibited immunohistochemical reactivity for MIC-2, consistent with a PPNET.
The association of Horner’s syndrome with C8/T1 cervical radiculopathy is classically seen in Pancoast’s syndrome, which is due to superior sulcus tumours of the lung that involve the chest wall and spinal column.7 The presentation of PPNET with Pancoast’s syndrome has been reported previously, but in this case the tumour had massively infiltrated the left thorax with widespread metastases, resulting in death at 17 weeks following initial diagnosis.8 In contrast, our patient presented with Horner’s syndrome at a relatively early stage of the disease, since the PPNET was localised with no evidence of metastatic spread. The malignant nature of this tumour highlights the importance of comprehensively investigating any patient with Horner’s syndrome, especially when associated with cervical radiculopathy.
We thank Dr Maria Thom, MRCPath, Division of Pathology, Institute of Neurology, London, for her assistance and permission in the preparation of pathological figures.