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Paravertebral Mass in a Patient With Thalassemia Intermedia
roentgenogram of the month Paravertebral Mass in a Patient With Thalassemia lntermedia* Rafiqul Alam, MB, BS; Krishnan Padmanabhan, MB, BS, RCCP; and I-lemalatha Rao, MB, BS
(CHEST 1997; 112:265-67)
A 41-year-old man was referred for evaluation of an abnormal chest roentgenogram. At age 10 years while he was living in Pakistan, a diagnosis of anemia secondary to thalassemia intermedia was made. Management of the anemia, while in Pakistan, included transfusion of about 100 units of blood over a period of many years and splenectomy at age 18 years. He has been in the United States for the last 10 years, during which time he eceived r chelation therapy for iron overload. A chest roentgenogram done during this period of time revealed alarge right paravertebral mass without a change in size. Examination revealed a patient of small stature with hepatomegaly. Laboratory data revealed a hemoglobin concentration of 10 gldL, a hematocrit level of 29%, a platelet count of 960,000/mm 3 , a WBC count of 11,100 mm 3 , mean corpuscular volume of 79 l-lm:3 and a reticulocyte count of 5.4%. The peripheral blood smear revealed anisocytosis, poikilocytosis, microcytosis, polychromatophilia, and Howell-Jolly bodies . H emoglobin electrophoresis revealed levels of HbF of 99% and HbA2 of 1.1 %. The chest roentgenogram (Fig 1) revealed a large well circumscribed right paravertebral mass, similar to that seen in the past chest roentgenograms. Th e ribs were wide and appeared trabeculated with irregular densities present along the margins. The chest CT scan with contrast (Fig 2) revealed a large right paravertebral mass and bilateral posterior and lateral
*From the Departmen ts of Pulmonary Medicine (Drs. A lam and Paclmanabhan) and Nuclear Medicine (Dr. Hao), Coney Island Hospital, and the State University of New York Health Science Center at Brooklyn (Dr. Padmanabhan ), Brooklyn , Y. Manuscript received September 23, 1996; revision accepted November 14. Reprint requests: Dr. Padmanabhan, Department of Pulmonary Medicine, Coney Island Hospital, 2601 Ocean Parkway, Brooklyn, NY 11235
FIGURE l. A posteroantf:'Jior chest roentgenogram showing a large right paravertebral mass and widened ribs.
2. CT scan of the chest with contrast medium showing the large paravertebral mass and bilateral poste rior and lateral paracostal masses. The bony cortex is intact. FIGURE
CHEST / 112 / 1 / JULY, 1997
265
paracostal masses. The bony cortex of the vertebral bodies and the ribs were intact and devoid of erosion. A 99 mTc sulfur colloid bone marrow scan (Fig 3) revealed intense uptake of the radioisotope by the right paravertebral mass comparable to the uptake by the humeral heads and liver. What is the diagnosis?
99 F IG URE 3. A "'Tc sulfi.1r colloid bone marrow scan showing intense radioisotope uptake by th e right paravertebral mass, liver, and hum eral heads.
266
Roentgenogram of the Month
Diagnosis: Intrathoracic extramedullary hematopoiesis
Extramedullary hematopoiesis (EMH) refers to the production of blood cells outside the bone marrow and is a compensatory mechanism for bone marrow dysfunction. This erythroid response is most often microscopic but can result in organomegaly or the development of tumor-like masses usually involving the liver, spleen, and lymph nodes . Less frequently involved sites include the kidney, the adrenal glands, the breasts, the spinal cord, the intrathoracic cavity, the pleura, the pericardium, and the intracranial cavity. 1 Thalassemia major or intermedia, congenital spherocytosis, congenital hemolytic anemia, and sickle cell anemia account for most cases of EMH.2 - 4 Bone marrow insufficiency seen in patients with myelofibrosis, carcinomatosis, lymphoma, and leukemia can also result in EMH. 2 Rarely, it is seen in Gaucher's disease, pernicious anemia, vitamin B12 and folate deficiency, Paget's disease, rickets, and hyperparathyroidism.2-5
DISCUSSION
Intrathoracic EMH is most often visualized on the chest roentgenogram or the chest CT scan as single or multiple paravertebral mass lesions. While a paravertebral mass may represent EMH, other disorders of the posterior mediastinum such as neurogenic tumor, lymphoma, primary and metastatic malignancy, paravertebral abscess, lateral meningocele, and extrapleural cyst must be considered. The characteristic features seen on the chest roentgenogram and the chest CT scan are helpful in recognizing intrathoracic EMH. 4 •5 These include the following: 1. Widening of the ribs, most marked at the vertebral end, by expansion of the medullary cavity or by periosteal elevation. 2. The presence of unilateral or bilateral wellcircumscribed lobulated, paravertebral mass lesions usually located caudal to the sixth thoracic vertebrae. The vertebral body is devoid of bony erosion and has a lacey appearance. 3. The presence of lateral or posterior, or both, subpleural paracostal masses located medial to the lateral portion of the ribs without bony erosion. The paracostal masses may or may not be contiguous with the paraspinal mass. 4. The absence of calcification and the presence of adipose tissue within the mass.
Radionuclide bone marrow scanning, using 99 mTc sulfur colloid is helpful in establishing the diagnosis. 6 MRI can be of additional diagnostic value by demonstrating the presence of adipose tissue within the mass and by confirming that the bony cortex is intact. 7 Intrathoracic EMH is most often asymptomatic, and rarely is treatment necessary. However, spinal cord compression requiring surgical intervention, symptomatic pleural effusion, massive hemothorax, and dyspnea secondary to involvement of lung interstitium have been reported.1 ·3 This hematopoietic tissue is extremely radiosensitive, and rapid reduction in the size of the mass or pleural effusion can be achieved by small doses of radiation. Intrathoracic EMH is a rarely encountered response to bone marrow dysfunction. Diagnosis made by noninvasive means is desirable, in view of the highly vascular nature of these hematopoetic masses. When the bone marrow dysfunction is obvious and intrathoracic EMH is suspected, the presence of the characteristic findings on a chest roentgenogram and chest CT scan should suffice to make the diagnosis. Bone marrow scanning with 99 mTc sulfur colloid is a convenient noninvasive method of further establishing the diagnosis. Tissue biopsy or surgical resection or both are reserved for those cases where extramedullary hematopoiesis is not suspected or when complications require surgical intervention.
REFERENCES
1 Bartlett RP, Greipp PR, Tefferi A, et a!. Extramedullary hematopoiesis manifesting as a symptomatic pleural effusion. Mayo Clin Proc 1995; 70:1161-64 2 Chen IY, Lynch DA, Shroyer KR, eta!. Gaucher's disease: an unusual cause of intrathoracic extramedullary he matopoiesis. Chest 1993; 104:1923-24 3 Verani R, Olson J, Moake JL. Intrathoracic extramedullary hematopoiesis: report of a case in a patient with sickle cell disease-B. Thalassemia. Am J Clin Pathol 1980; 73:133-37 4 Gumbs R, Ford EAH, Tea JS, et a!. Intrathoracic extramedullary hematopoiesis in sickle cell disease. AJR 1987; 149: 889-93 5 Fielding JR, Owens M, Naimark A. Intrathoracic extramedullary hematopoiesis secondary to B12 and folate deficiency: CT appearance. J Comput Assist Tomogr 1991; 15:308-10 6 Bronn LJ, Paguelet JR, Tetalman MR. Intrathoracic extramedullary hematopoiesis: appearance on Tc99m sulfur colloid marrow scan. AJR 1980; 134:1254-55 7 Sarader SJ, Otero RR, Sarader BL. MR imaging of intrathoracic extramedullary hematopoiesis. J Comput Assist Tomogr 1988; 12:878-80
CHEST I 112 I 1 I JULY, 1997
267
(CHEST 1997; 112:265-67)
A 41-year-old man was referred for evaluation of an abnormal chest roentgenogram. At age 10 years while he was living in Pakistan, a diagnosis of anemia secondary to thalassemia intermedia was made. Management of the anemia, while in Pakistan, included transfusion of about 100 units of blood over a period of many years and splenectomy at age 18 years. He has been in the United States for the last 10 years, during which time he eceived r chelation therapy for iron overload. A chest roentgenogram done during this period of time revealed alarge right paravertebral mass without a change in size. Examination revealed a patient of small stature with hepatomegaly. Laboratory data revealed a hemoglobin concentration of 10 gldL, a hematocrit level of 29%, a platelet count of 960,000/mm 3 , a WBC count of 11,100 mm 3 , mean corpuscular volume of 79 l-lm:3 and a reticulocyte count of 5.4%. The peripheral blood smear revealed anisocytosis, poikilocytosis, microcytosis, polychromatophilia, and Howell-Jolly bodies . H emoglobin electrophoresis revealed levels of HbF of 99% and HbA2 of 1.1 %. The chest roentgenogram (Fig 1) revealed a large well circumscribed right paravertebral mass, similar to that seen in the past chest roentgenograms. Th e ribs were wide and appeared trabeculated with irregular densities present along the margins. The chest CT scan with contrast (Fig 2) revealed a large right paravertebral mass and bilateral posterior and lateral
*From the Departmen ts of Pulmonary Medicine (Drs. A lam and Paclmanabhan) and Nuclear Medicine (Dr. Hao), Coney Island Hospital, and the State University of New York Health Science Center at Brooklyn (Dr. Padmanabhan ), Brooklyn , Y. Manuscript received September 23, 1996; revision accepted November 14. Reprint requests: Dr. Padmanabhan, Department of Pulmonary Medicine, Coney Island Hospital, 2601 Ocean Parkway, Brooklyn, NY 11235
FIGURE l. A posteroantf:'Jior chest roentgenogram showing a large right paravertebral mass and widened ribs.
2. CT scan of the chest with contrast medium showing the large paravertebral mass and bilateral poste rior and lateral paracostal masses. The bony cortex is intact. FIGURE
CHEST / 112 / 1 / JULY, 1997
265
paracostal masses. The bony cortex of the vertebral bodies and the ribs were intact and devoid of erosion. A 99 mTc sulfur colloid bone marrow scan (Fig 3) revealed intense uptake of the radioisotope by the right paravertebral mass comparable to the uptake by the humeral heads and liver. What is the diagnosis?
99 F IG URE 3. A "'Tc sulfi.1r colloid bone marrow scan showing intense radioisotope uptake by th e right paravertebral mass, liver, and hum eral heads.
266
Roentgenogram of the Month
Diagnosis: Intrathoracic extramedullary hematopoiesis
Extramedullary hematopoiesis (EMH) refers to the production of blood cells outside the bone marrow and is a compensatory mechanism for bone marrow dysfunction. This erythroid response is most often microscopic but can result in organomegaly or the development of tumor-like masses usually involving the liver, spleen, and lymph nodes . Less frequently involved sites include the kidney, the adrenal glands, the breasts, the spinal cord, the intrathoracic cavity, the pleura, the pericardium, and the intracranial cavity. 1 Thalassemia major or intermedia, congenital spherocytosis, congenital hemolytic anemia, and sickle cell anemia account for most cases of EMH.2 - 4 Bone marrow insufficiency seen in patients with myelofibrosis, carcinomatosis, lymphoma, and leukemia can also result in EMH. 2 Rarely, it is seen in Gaucher's disease, pernicious anemia, vitamin B12 and folate deficiency, Paget's disease, rickets, and hyperparathyroidism.2-5
DISCUSSION
Intrathoracic EMH is most often visualized on the chest roentgenogram or the chest CT scan as single or multiple paravertebral mass lesions. While a paravertebral mass may represent EMH, other disorders of the posterior mediastinum such as neurogenic tumor, lymphoma, primary and metastatic malignancy, paravertebral abscess, lateral meningocele, and extrapleural cyst must be considered. The characteristic features seen on the chest roentgenogram and the chest CT scan are helpful in recognizing intrathoracic EMH. 4 •5 These include the following: 1. Widening of the ribs, most marked at the vertebral end, by expansion of the medullary cavity or by periosteal elevation. 2. The presence of unilateral or bilateral wellcircumscribed lobulated, paravertebral mass lesions usually located caudal to the sixth thoracic vertebrae. The vertebral body is devoid of bony erosion and has a lacey appearance. 3. The presence of lateral or posterior, or both, subpleural paracostal masses located medial to the lateral portion of the ribs without bony erosion. The paracostal masses may or may not be contiguous with the paraspinal mass. 4. The absence of calcification and the presence of adipose tissue within the mass.
Radionuclide bone marrow scanning, using 99 mTc sulfur colloid is helpful in establishing the diagnosis. 6 MRI can be of additional diagnostic value by demonstrating the presence of adipose tissue within the mass and by confirming that the bony cortex is intact. 7 Intrathoracic EMH is most often asymptomatic, and rarely is treatment necessary. However, spinal cord compression requiring surgical intervention, symptomatic pleural effusion, massive hemothorax, and dyspnea secondary to involvement of lung interstitium have been reported.1 ·3 This hematopoietic tissue is extremely radiosensitive, and rapid reduction in the size of the mass or pleural effusion can be achieved by small doses of radiation. Intrathoracic EMH is a rarely encountered response to bone marrow dysfunction. Diagnosis made by noninvasive means is desirable, in view of the highly vascular nature of these hematopoetic masses. When the bone marrow dysfunction is obvious and intrathoracic EMH is suspected, the presence of the characteristic findings on a chest roentgenogram and chest CT scan should suffice to make the diagnosis. Bone marrow scanning with 99 mTc sulfur colloid is a convenient noninvasive method of further establishing the diagnosis. Tissue biopsy or surgical resection or both are reserved for those cases where extramedullary hematopoiesis is not suspected or when complications require surgical intervention.
REFERENCES
1 Bartlett RP, Greipp PR, Tefferi A, et a!. Extramedullary hematopoiesis manifesting as a symptomatic pleural effusion. Mayo Clin Proc 1995; 70:1161-64 2 Chen IY, Lynch DA, Shroyer KR, eta!. Gaucher's disease: an unusual cause of intrathoracic extramedullary he matopoiesis. Chest 1993; 104:1923-24 3 Verani R, Olson J, Moake JL. Intrathoracic extramedullary hematopoiesis: report of a case in a patient with sickle cell disease-B. Thalassemia. Am J Clin Pathol 1980; 73:133-37 4 Gumbs R, Ford EAH, Tea JS, et a!. Intrathoracic extramedullary hematopoiesis in sickle cell disease. AJR 1987; 149: 889-93 5 Fielding JR, Owens M, Naimark A. Intrathoracic extramedullary hematopoiesis secondary to B12 and folate deficiency: CT appearance. J Comput Assist Tomogr 1991; 15:308-10 6 Bronn LJ, Paguelet JR, Tetalman MR. Intrathoracic extramedullary hematopoiesis: appearance on Tc99m sulfur colloid marrow scan. AJR 1980; 134:1254-55 7 Sarader SJ, Otero RR, Sarader BL. MR imaging of intrathoracic extramedullary hematopoiesis. J Comput Assist Tomogr 1988; 12:878-80
CHEST I 112 I 1 I JULY, 1997
267