INTRODUCTION: The wide variety of thymic diseases offer a unique window to observe the complex interaction leading to an autoimmune diathesis.
CASE PRESENTATION: A 29 year-old, previously healthy, African-American male patient complained of 4 week-history of progressive shortness of breath, non-productive cough and left sided chest pain. Chest radiograph revealed complete opacification of the left hemithorax with shift of the mediastinum to the right. Computed tomography of the chest demonstrated a large left-sided pleural effusion and a large anterior mediastinal mass. The patient underwent a left thoracocentesis. Fluid analysis was suggestive of chylothorax. PET scan showed anterior mediastinal mass with no significant increased activity. Laboratory data including blood, urine, AFB's were normal. Patient underwent an open biopsy of the anterior mediastinal mass with the resultant pathology specimen being consistent with lymphocytic predominant epithelial type thymoma. Due to the invasive behavior of this neoplasm, an initial surgical treatment was deferred and patient was discharged home to be started on 4 drug-regimen chemotherapy (Adriamycin, Cisplatin, Vincristine, Cyclophosphamide) every 3 weeks on an outpatient basis. After 72 hours from being discharged, and before receiving any chemotherapy, patient started having severe bilateral lower extremity pain, muscle cramps and weakness in both legs. The patient did not have any shortness of breath, change in his bowel habits, headache, double vision, dysphagia or other neurologic symptoms. Repeated physical examination at that time, revealed evidence of an unsteady antalgic gait with weakness of hip joint and flexors and extensor muscle weakness. The patient had diffuse muscle stiffness in both lower extremities along with diffuse back pain. Rest of the neurologic examination was normal. Patient was given diazepam 5 mg intravenously along with intravenous morphine with complete resolution of his symptoms. In order to rule out other associated disorders a full laboratory work up was done including a paraneoplastic panel which was negative. Mysthenia gravis was ruled out by a normal pulmonary function test and a negative anti-ach antibodies. Based on the clinical picture, excluding other etiologies, and the dramatic response to benzodiazepine and opiates the diagnosis of Stiff-man syndrome (SMS) was made. Patient received chemotherapy as planned and at 5 month- follow up he feeling much better being tapered off benzodiazepine and opiate with complete resolution of his radiographic and clinical symptoms.
DISCUSSIONS: SMS, since its early description, has been found to be associated with a variable spectrum of clinical presentations, making its diagnosis quite challenging. We present the 10th case of SMS associated with thymoma to be described in the world literature. The proposed criteria for this syndrome include the following: evidence of muscular stiffness and axial rigidity, impairment of ambulation secondary to muscular stiffness, pronounced lordosis, presence of additional muscular spasms that are precipitated by sudden trigger such as emotion, loud noise, or movement, normal motor and sensory examination, characteristic EMG findings of continuous motor unit activity resolving by diazepam, normal intellect, presence of either anti-glutamic acid decarboxylase antibodies (GAD) (60%) or anti-amphiphysin antibodies (<5%). Our patient met 5 out of 8 criteria.
CONCLUSION: While rare, it is important for clinicians to be aware of the association of thymoma and SMS. SMS is best approached by early recognition and prompt treatment. An intensive search for the underlying etiology is essential because SMS can be a paraneoplastic syndrome or secondary to other treatable causes.
DISCLOSURE: Semaan Kosseifi, No Financial Disclosure Information; No Product/Research Disclosure Information