Intrathoracic Malignancy Mimicking Axial Dystonia
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Intrathoracic malignancy mimicking axial dystonia. Patient (28 years old) with a 5-year history of fixed postural deformity of the trunk and initial diagnosis of functional movement disorder. Although a normal MRI spine, pleuritic pain and unilateral hyperhydrosis prompted us to look into the thorax.
Marianna Selikhova MRCP, PhD, Karen M. Doherty MRCP, MD, Mark J. Edwards MRCP, PhD, Katherine A. Buzzard PhD, MD and Andrew J. Lees FRCP, FMedSci
Article first published online: 28 NOV 2015 | DOI: 10.1002/mdc3.12262
A 28-year-old woman was referred to the movement disorders clinic at the National Hospital for Neurology and Neurosurgery for investigation of lateral spinal flexion deformity of the trunk and a working diagnosis of a functional (psychogenic) movement disorder. She had a 5-year history of persistent right-sided chest pain, which started during her final university exams, followed by the gradual development of a fixed abnormal posture of the trunk, tilting her to the right. MRI brain and spine were normal. Abnormal posture and pain worsened over time. She had an examination under anesthetic in an orthopedic unit where there was an almost complete correction of her scoliotic deformity. She was placed in a plaster cast to maintain the corrected posture; however, it was immediately removed because of severe breathlessness. The patient was otherwise fit and well. She had no other medical illnesses, including no history of mental health problems. Her only medication was paracetamol for pain relief. There was no family history of dystonia.
Clinical examination revealed a marked deformity of her posture with truncal shift to the left and a large thoracic curve (convex to the left) without rotational component. Her left shoulder was elevated and her pelvis was higher on the right (Fig. 1). Lateral flexion was minimal, likely owing to the S-shaped nature of the curve.
There was tenderness on palpation over the right chest wall and right shoulder tip with hyperesthesia and allodynia. She was able to self-correct the posture with guidance, however was unable to maintain a normal posture. There were no jerky movements, palpable contractions of back or abdominal muscles, and no sensory geste. Pain and spinal curvature continued when she lay in bed at night. She did not have fixed knee or hip flexion contractures, and her posture did not change with position (supine, sitting, standing, or walking). There was anisocoria (dark: right, 7 mm; left, 6 mm; bright light: right, 4 mm; left, 3 mm) and hyperhidrosis of the right hand and axilla. The remainder of the neurological examination was entirely normal (Video 1).
Figure 1. Marked truncal deformity with a large thoracic curve (convex to the left). Patient's left shoulder elevated and pelvis was higher on the right
Needle electromyography was normal. Thermoregulatory sweat testing revealed profuse general sweating, but in the face this was observed more on the right side. The presence of chest pain, anisocoria, and unilateral hyperhidrosis prompted a CT chest investigation. A pericardial mass indenting the right atrium and distal superior vena cava (SVC) was identified. There were also a right middle lobe nodule, a number of lung parenchymal nodules extending into the pleural, including the right posterior chest wall, and a right subdiaphragmatic lesion (Fig. 2). The left thorax was clear. Histology revealed metastatic atypical bronchial carcinoid tumor originating from the right middle lobe. She was treated with middle lobectomy, multiple resections of the metastatic lesions, and seven cycles of chemotherapy FCarboStrep (fluorouracil, carboplatin, and Streptozotocin). This has resulted in disease stability, but not resolution of her abnormal posture.
Figure 2. CT chest findings. There is a right-sided solid pericardial mass 3.3 × 3.4 cm, adjacent to the right atrium and causing extrinsic compression of the SVC (image on the left). There is also a nodular thickening of the right pleura posteriorly and paravertebrally, 0.7-cm nodule on the diaphragmatic surface of the right pleura, and 1-cm nodule in the lateral segment of the right middle lobe (image on the right)
This is a case of gradually progressive persistent thoracic scoliosis in a young adult secondary to a mediastinal mass lesion that remained undiagnosed for over 5 years. Onset at a young age, in a female, during a period of stress and a normal appearance on spinal and brain imaging led to the initial diagnosis of functional dystonia. Fixed dystonias of a sudden onset are most often a result of functional neurological disease, as opposed to an inherited dystonic disorder such as DYT1, where dystonia is usually dynamic and varies with position. However, a diagnosis of functional fixed dystonia is inappropriate in the context of gradual, rather than sudden, onset.
A lateral deviation of the trunk, which is not a result of structural problems in the spine, sometimes named Pisa syndrome, is observed in the setting of Parkinson's disease and MSA or secondary to neuroleptic use (tardive dystonia). Brain tumor and arteriovenous malformation can present with dystonic movements and/or postures, identical to those observed in genetic forms of dystonia.[2-4] Cases of dystonic spasm limited to the paraspinal muscles, responsive to trihexyphenidyl, have been reported after closed head injury. Our patient had never been on any neuroleptic medication to suggest this was a tardive dystonia and had no extra-axial dystonia or other neurological signs to suggest primary dystonia or secondary degenerative or metabolic disorders. Her clinical presentation of a fixed, rather than mobile, abnormal posture would be unusual for nondegenerative forms of dystonia. The abnormal posture may have developed initially as a way of relieving pain from the irritative chest wall and mediastinal lesions, which, after a prolonged period, resulted in secondary muscle tendon shortening.
Chest pain, anisocoria, and unilateral sweating were red flags for an underlying intrathoracic structural lesion in our patient. Sympathetic neurological complications, especially Horner's syndrome, are reported in cases of intrathoracic malignancy. Unilateral sweating is, however, a rare phenomenon, associated with advanced tumor and usually signal encroachment of an ipsilateral lesion on the sympathetic chain ganglia or postganglionic sympathetic fibers, as evidenced by a few postmortem findings.[7, 8] The unilateral right-sided hyperhidrosis in our case likely reflects infiltration of the sympathetic postganglionic fibers by the ipsilateral lesion, such as metastatic nodular thickening paravertebrally and right pericardial mass. Her left-sided partial Horner's syndrome possibly is contralateral, as a result of a localized sympathetic preganglionic overactivity. To conclude, there are a number of causes of abnormal truncal posture, and careful clinical assessment is needed. It is important to consider looking into the thorax, and not only the spine, when assessing a patient with truncal postural deformity.