|Year : 2015 | Volume
| Issue : 4 | Page : 1034
Extramedullary hematopoiesis on 18F-FDG PET/CT in a patient with thalassemia and nasopharyngeal carcinoma: A case report and literature review
Dasheng Qiu1, Xiaoyan Hu1, Liying Xu2, Xiaofang Guo1
1 Positron Emission Tomography/Computed Tomography Center, Hubei Province Cancer Hospital, Wuhan, China
2 Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
|Date of Web Publication||15-Feb-2016|
Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan 430071
Source of Support: None, Conflict of Interest: None
Extramedullary hematopoiesis (EMH) occurs in various bone marrow disorders and is most commonly seen in thalassemia and myelofibrosis. Here, we report a patient with beta-thalassemia and nasopharyngeal carcinoma having intrathoracic EMH. Our patient is a 42-year-old man who complained of chest discomfort for a month. He was confirmed nasopharyngeal carcinoma (T3N2M0) by histopathology and received chemoradiotherapy 4 months ago. The patient had a long history of beta-thalassemia and a splenectomy due to splenomegaly at 12 years of age. Computed tomography (CT) scan of the chest showed multiple soft tissue masses in bilateral thoracic cavities. 18F-FDG-PET showed no obvious increase of fluorodeoxyglucose (18F-FDG) uptake by the lesions, with an SUVmax value of approximately 2.19. These lesions were considered EMH. The patient had been followed up for more than 1 year, and there were no changes of the lesions in the thoracic cavities.
Keywords: Extramedullary hematopoiesis, fluoro-2-deoxyglucose, nasopharyngeal carcinoma, positron emission tomography/computed tomography, thalassemia
|How to cite this article:|
Qiu D, Hu X, Xu L, Guo X. Extramedullary hematopoiesis on 18F-FDG PET/CT in a patient with thalassemia and nasopharyngeal carcinoma: A case report and literature review. J Can Res Ther 2015;11:1034
|How to cite this URL:|
Qiu D, Hu X, Xu L, Guo X. Extramedullary hematopoiesis on 18F-FDG PET/CT in a patient with thalassemia and nasopharyngeal carcinoma: A case report and literature review. J Can Res Ther [serial online] 2015 [cited 2018 Jul 17];11:1034. Available from: http://www.cancerjournal.net/text.asp?2015/11/4/1034/150359
| > Introduction|| |
Thalassemia occurs in a broad geographical band from the Mediterranean through Asia. In China, thalassemia is more prevalent in Guangdong province, and is commonly accompanied by extramedullary hematopoiesis (EMH). This hematopoietic response is most often microscopic, but can also result in organomegaly or the development of tumor-like masses, usually affecting the liver, spleen, lymph nodes, and intrathoracic cavity. Magnetic resonance imaging (MRI) and computed tomography (CT) scans are used most commonly to detect EMH. This article presents one case of paraspinal EMH in a patient with nasopharyngeal carcinoma (T3N2M0) and a long history of thalassemia.
| > Case report|| |
A 42-year-old man was admitted to our hospital due to persistent chest discomfort for a month. He was confirmed nasopharyngeal carcinoma (T3N2M0) by histopathology and had received chemoradiotherapy 4 months ago. The patient has a long history of beta-thalassemia and had a splenectomy due to splenomegaly at 12 years of age. Abnormal laboratory findings were as follows: Hb: 8.5 g/dl, WBC: 21.89 × 10 9 /L, and PLT: 40 g/L. Computed tomography scan showed multiple paravertebral nodules in bilateral thoracic cavities. Metastasis could not be excluded, based on his medical history. FDG PET/CT was performed to evaluate the paravertebral masses and to determine whether there were other lesions. PET/CT showed multiple symmetric paravertebral soft-tissue nodules with the biggest measuring 2.9 cm × 2.0 cm, part of which displayed clear borders; the density on CT was uniform and had a CT value of 35.0HU [Figure 1]. On PET imaging, a mild radioactive accumulation was observed in these lesions, with standardized uptake value (SUV) max of 2.19 [Figure 2]. These lesions were thought to be benign in origin. No pleural effusion was observed. Diffuse and decreased bone density was found in bilateral scapula, ribs, sternum, and centrum without obvious abnormal radioactive distribution. In Technetium-99-methylene bisphosphonate bone Emission Computed Tomography (ECT 99m Tc-MDP) imaging, no abnormal radioactive distribution was found in bones of the whole body. According to all these imaging findings and his medical history of thalassemia, these multiple paravertebral soft-tissue lesions were considered EMH. The patient had been followed up for more than 1 year, and there were no changes of the lesions in the thoracic cavities.
|Figure 1: Plain CT scan showing multiple symmetric paravertebral soft-tissue nodules. The biggest 2.9 cm × 2.0 cm in size. Some nodules show clear boundaries and uniform density. CT value about 35.0 HU|
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|Figure 2: PET/CT showing multiple paravertebral soft-tissue nodules. 18F-FDG-PET/CT revealed no obvious abnormal radioactive accumulation with maximum standardized uptake value (SUVmax) of 2.19|
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| > Discussion|| |
Clinical characteristics of EMH in thalassemia
Extramedullary hematopoiesis is considered as a compensatory reaction in patients with chronic anemia such as thalassemia. Insufficient production of blood elements in the marrow of long bones, ribs, and the vertebrae for blood circulation is remarkable among these patients. The liver, spleen, kidney, and lymph nodes are the most common sites of EMH, whereas the intrathoracic cavity is less frequently involved. , Intrathoracic EMH masses are generally located in the posterior mediastinum but can also manifest as interstitial pulmonary abnormality, pleural mass, or hemothorax, either alone or in combination. EMH can be single or multiple and may present bilaterally.
It is usually asymptomatic but can sometimes lead to clinical symptoms due to compression of neighboring structures by hematopoietic tissues. Some case reports presented EMH causing spinal cord compression in recent years. , Extramedullary hematopoiesis usually regresses or disappears after treatment with blood transfusions and hydroxyurea. Radiation therapy or surgical intervention can be required in case of clinical symptoms. Oral administration of hydroxyurea was preferred in this case as patients' symptoms were mild.
Imaging characteristics of intrathoracic EMH in thalassemia
On plain chest radiography, intrathoracic EMH lesions have predilection for the lower thoracic spine region. They usually appear as smooth or lobulated posterior mediastinal mass, which can be unilateral or bilateral, isolated or widespread. On plain CT, EMH lesions appear as soft tissues masses that are homogeneous. On contrast with enhanced CT, EMH lesions enhance inhomogeneously owing to the iron deposition and fat infiltration. In patients with a known primary malignancy, it may be difficult to differentiate EMH from metastasis. In patients with chronic anemia not requiring hyper-transfusion, some appearance of osteopenia, medullary expansion, coarse trabecular pattern, and cortical thinning can be found on CT.  In this case, diffuse and decreased bone density was found.
Magnetic Resonance Imaging (MRI) is most commonly used for detecting EMH, whereas PET/CT is less used. ,, MRI clearly showed the site and extent of the lesion in relation to the spinal canal. It is considered more beneficial than CT.  The EMH lesions may show different degrees of intensity on T1- and T2-weighted images. However, mixture of blood products of different stage within the EMH results in increased or decreased signal. Some masses show a peripheral hyperintense rim that is attributed to fat. This distinguishes EMH lesions from metastasis and other lesions.
With PET/CT, EMH lesions demonstrate mild to moderate metabolic activity when compared with malignant lesions, which demonstrate high metabolic activity. In our case, the patient had a history of nasopharyngeal carcinoma and beta-thalassemia. Intrathoracic metastasis and EMH should be distinguished. Extramedullary hematopoiesis was detected as multiple benign-appearing masses on PET/CT with a very low SUVmax in this case,  which suggested benign tumor. The PET/CT is helpful to confirm the diagnosis of EMH in patient with malignant tumor.
| > References|| |
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[Figure 1], [Figure 2]