An Unusual Combination: Rhabdomyosarcoma of the Anterior Mediastinum
John C. Vandover MD, Associate
Christiana Care Health System, Newark, DE
Case: 21 y.o. previously healthy Caucasion female presented to the emergency department with atypical chest pressure, a 20 pound weight loss, anorexia and dyspnea with deep inspiration. Her past history was remarkable for an 8 pack year smoking history. Her physical exam was unremarkable.
A PA and lateral chest x-ray and contrast enhanced chest CT scan demonstrated a well circumscribed homogeneous 8 x 10 x 13 cm. anterior mediastinal mass. On CT guided fine needle biopsy a neoplasm was found with myxoid differentiation. There was no evidence of lymphoma or thymoma. A metastatic workup was negative. At surgical resection by median sternotomy, the mass was much larger than that seen on CT. It was densely adherent to the pericardium, mediastinal pleura and left lung with encasement of a portion of the left pulmonary artery. A complete surgical resection was undertaken including a left pneumonectomy in a wide en bloc resection with negative margins. Pathology revealed a primary anterior mediastinal rhabdomyosarcoma anatomically related to the thymus, thought to have an origin from myoid type cells. Following surgery the patient underwent chemotherapy with the VAC regimen (vincristine, adriamycin, and cytoxan) alternating with a regimen of ifosfamide and VP-16. Subsequent radiation therapy is planned.
Discussion: The differential diagnosis for anterior mediastinal masses includes thymomas, lymphomas (both Hodgkins and poorly differentiated non Hodgkins), germ cell tumors and more benign entities including cysts from a variety of sources (pericardial, bronchogenic, enteric, thymic, thyroid, and parathyroid). Rhabdomyosarcoma is very rare in adults. It is a malignant tumor of striated muscle origin and is the most common soft tissue sarcoma seen in children, most often in the head and neck regions. Histologies include embryonal, alveolar, botryoid and pleomorphic. Embryonal is the most common type in children, pleomorphic in adults. There are several staging systems employed, including the TNM system.
Mediastinal rhabdomysarcoma is a very rare diagnosis, sparsely reported in the literature, and often seen in association with other tumors including malignant teratoma, nonteratomatous germ cell tumor, and thymic carinosarcoma. Mediastinal rhabdomyosarcomas appear to have an aggressive course with rapid progression to death and have not been found to be responsive to current surgical and chemotherapeutic modalities. The most common chemotherapeutic regimen is the VAC protocol. Chemotherapy is typically employed for 2-3 months followed by 5-6 weeks of external beam radiation. If there is a parameningeal focus with meningeal spread, then radiation and whole brain irradiation is initiated at the time of chemotherapy. Surgery plays a limited role in more advanced disease.
Selected References:
Suster, S et al. "Rhabdomyosarcomas of the Anterior Mediastinum: Report of Four Cases Unassociated with Germ Cell, Teratomatous, or Thymic Carcinomatous Components." Human Pathology 25(4): April 1994, 349 - 356.
Thurer, RL "Evaluation of Mediastinal Masses" UptodateOnline 11.1 2003.
An Unusual Combination: Schizophrenia and Hypertensive Encephalopathy
John C. Vandover M.D, Associate
Christiana Care Health System, Newark, DE
Case: A 43-year-old African American male with a history of schizophrenia presented with three days of threatening behavior, combativeness and recent medication noncompliance. He also noted painless hematuria. There was no history of head trauma, headache, fever, neck stiffness or chest pain. Initially, he was given several intravenous doses of haldol for management of combativeness.
His blood pressures were 215 - 230 over 150 mm Hg in both arms. Papilledema was present, and an S4 heart sound was noted. His neck was supple, and his neurologic examination was nonfocal. An unenhanced head CT scan showed mild cerebral edema. His EKG met voltage criteria for left ventricular hypertrophy. His blood urea nitrogen was 18 mg/dL, creatinine 2.4 mg/dL, serum sodium 129 mEq/L, potassium 2.3 mEq/L; the anion gap was normal. Plasma renin activity, serum glucose and aldosterone levels were normal. There was 2+ proteinuria on urine dipstick with 50 red blood cells per high power field on a spun specimen. A urine drug screen was negative. The kidneys were of normal size by ultrasound, without renal artery stenosis by Doppler interrogation. He was diagnosed with hypertensive encephalopathy. His blood pressure was controlled with intravenous nitroprusside. Thereafter, he was started on oral labetolol and clonidine with electrolyte normalization but persistence of his elevated creatinine.
Discussion: Hypertensive encephalopathy, a form of malignant hypertension, is a hypertensive emergency in which cerebral hyperperfusion results in cerebral edema, causally related to severe or rapid rises in blood pressure overcoming cerebral autoregulation. It often occurs in the setting of longstanding hypertension in patients who abruptly stop their medical therapies.
Malignant hypertension mediates its end organ effects by way of endothelial damage leading to fibrinoid necrosis within arterioles and capillaries. Patients with chronic baseline hypertension will have some arteriolar hypertrophy; the level at which they may experience damage from surges in blood pressure may be higher than in naive patients. Usually, patients with malignant hypertension have diastolic pressures of 130 mm Hg or greater, although hypertensive encephalopathy can be seen with diastolic pressures as low as 100 mm Hg.
Clinical signs include retinal hemorrhages, exudates and papilledema; malignant nephrosclerosis with proteinuria and hematuria; and neurologic changes with intracerebral or subarachnoid hemorrhages. Typical unenhanced CT scan findings include cerebral edema and posterior leukoencephalopathy.
Treatment goals are to rapidly lower the diastolic pressure over 2 to 6 hours to 100 - 105 mm Hg. Once this has been achieved, the patient is switched to oral therapy with a goal diastolic pressure of 85 to 90 mm Hg over several months.
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