Elliot K. Fishman M.D.
Johns Hopkins Hospital

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“In the era of cross-sectional imaging, mediastinal abnormalities can easily be identified. However, these abnormalities often manifest initially at conventional radiography. Chest radiography is a very common examination, and radiographic identification of an unexpected mediastinal mass is important. Knowledge of the normal mediastinal reflections that can be appreciated at conventional radiography is crucial to identifying a mediastinal mass. These mediastinal reflections can also help identify the location of a mass, thereby aiding in differential diagnosis and possibly influencing the choice of modality for further assessment.”
A Diagnostic Approach to Mediastinal Abnormalities
Camilla R. Whitten et al.
RadioGraphics 2007; 27:657– 671

“The radiographic features of b-thalassemia are due in large part to marrow hyperplasia. Markedly expanded marrow space lead to various skeletal manifestations including spine, skull, facial bones, and ribs. Extramedullary hematopoiesis (ExmH), hemosiderosis, and cholelithiasis are among the non-skeletal manifestations of thalassemia. The skeletal X-ray findings show characteristics of chronic overactivity of the marrow.”
Imaging features of thalassemia 
M. Tunacõ et al.
Eur. Radiol. 9, 1804±1809 (1999)

“Extramedullary hematopoiesis represents the body's attempt to maintain erythrogenesis when there is an important alteration in blood cell population. In thalassemia, posterior mediastinal paravertebral masses or presacral masses represent sites of ExmH resulting from extraosseous extension of medullary tissue. Also ExmH can arise from pluripotential stem cells distributed throughout the body, and involvement of the abdominal viscera, including liver, spleen, kidneys, adrenal glands, and breast, may occur.”
Imaging features of thalassemia 
M. Tunacõ et al.
Eur. Radiol. 9, 1801-1809 (1999)

“Extramedullary haematopoiesis (EMH)EMH may be classified as paraosseous or extraosseous and is more common in NTDT than in regularly transfused TDT. Paraosseous EMH typically occurs in the thoracic region, followed by the lumbar region. This appears as lobulated posterior mediastinum soft-tissue masses involving the posterior rib segments, or less often the anterior ends of ribs or presacral region.”
Imaging features of thalassaemia
Maria Gosein et al.
Br J Radiol. 2019 Apr; 92(1096): 20180658.

-hereditary spherocytosis
-sickle cell anemia
-congenital dyserythropoietic anemia
-immune thrombocytopenic purpura
-chronic myeloid leukemiapolycythemia vera
-myelodysplastic syndrome 
-Paget’s disease
-osteopetrosis
-Gaucher disease
-treatment with myeloid growth factors

“The commonest sites of EMH in the abdomen are the liver, spleen, and lymph nodes, all sites of in utero hemopoietic activity. Signs and symptoms include hepatosplenomegaly and abdominal discomfort, as well as shortness of breath in the case of massive enlargement. Pain can be the presenting symptom if splenic infarction occurs. Hepatosplenomegaly can be detected on cross-sectional imaging (CT, MRI, and ultrasound) and 99mTc methylene diphosphonate whole-body bone scan.”
Extramedullary Hemopoiesis
EleniOrphanidou-Vlachou et al.
Seminars in Ultrasound, CT and MRIVolume 35, Issue 3, June 2014, Pages 255-262