Respiratory Medicine CME
Volume 2, Issue 3 , Pages 118-120, 2009

Thoracic extramedullary hematopoiesis: A diagnosis to not forget in a patient with posterior mediastinal mass with anemia

  • Wajdi Ketata

      Affiliations

    • Department of Pulmonary and Allergology Diseases, Hedi Chaker Hospital, Sfax 3029, Tunisia
    • Corresponding Author InformationCorresponding author. Tel.: +33 216 98952545; fax: +33 216 74241384.
    • ,
  • Sameh Msaad

      Affiliations

    • Department of Pulmonary and Allergology Diseases, Hedi Chaker Hospital, Sfax 3029, Tunisia
    • ,
  • Hamida Kwass

      Affiliations

    • Department of Pulmonary and Allergology Diseases, Hedi Chaker Hospital, Sfax 3029, Tunisia
    • ,
  • Imene Gargouri

      Affiliations

    • Department of Pulmonary and Allergology Diseases, Hedi Chaker Hospital, Sfax 3029, Tunisia
    • ,
  • Mohamed Makki Gheriani

      Affiliations

    • Department of Pathology, Habib Bouguiba Hospital, Sfax, Tunisia
    • ,
  • Naourez Gouiaa

      Affiliations

    • Department of Pathology, Habib Bouguiba Hospital, Sfax, Tunisia
    • ,
  • Chaouki Dabbech

      Affiliations

    • Department of Radiology, Habib Bouguiba Hospital, Sfax, Tunisia
    • ,
  • Tahia Boudawara

      Affiliations

    • Department of Pathology, Habib Bouguiba Hospital, Sfax, Tunisia
    • ,
  • Abdelkader Ayoub

      Affiliations

    • Department of Pulmonary and Allergology Diseases, Hedi Chaker Hospital, Sfax 3029, Tunisia

Article Outline

Summary 

The most common masses occurring in the posterior mediastinum are tumors of nerve-cell origin. Other several etiologies can be evoked such as tuberculous abscess, bronchogenic malignancies, esophageal tumors, lymphomas and ectopic hematopoiesis.

We report a case of extramedullary hematopoiesis presenting as posterior mediastinal masses in a 63-year-old woman with congenital dyserythropoietic anemia. The diagnosis was confirmed by a CT-guided fine needle biopsy.

Thoracic extramedullary hematopoiesis represents a rare phenomenon complicating several chronic hemopathies. This diagnosis should be born in mind in front of posterior mediastinal masses in a patient with chronic hemolytic anemia in order to avoid dangerous surgical interventions.

Keywords: Posterior mediastinum, Extramedullary hematopoiesis, Congenital dyserythropoietic anemia

 

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1. Introduction 

The most common masses occurring in the posterior mediastinum are tumors of nerve-cell origin. Other several etiologies can be evoked such as tuberculous abscess, bronchogenic malignancies, esophageal tumors, lymphomas and ectopic hematopoiesis. Their exact frequency is unknown.1 We report a case of extramedullary hematopoiesis (EMH) presenting as posterior mediastinal masses that were symptomatic and confirmed by fine needle biopsy.

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2. Case report 

A 63-year-old woman was referred to the Pulmonary Department of Sfax Hospital (Tunisia) because of a 2-week history of increasing breathlessness, dry cough, pleuritic left chest pain and fatigue. Past history disclosed anemia diagnosed at the age of 10 years requiring blood transfusions and since the patient was lost sight of.

Initial physical examination revealed a blood pressure of 120/70mmHg, pulse rate of 80beats/min, respiratory rate of 24breaths/min. Chest examination showed decreased breath sounds at the right lower lung. Splenomegaly was noted on abdominal palpation without hepatomegaly.

Laboratory data revealed a normocytic, normochrome anemia (hemoglobin: 6.5g/dL, mean corpuscular volume: 89fL, mean corpuscular hemoglobin concentration: 30.6g/dL), nonregenerative (83,000reticulocytes/mm3). The peripheral blood smear examination disclosed marked anisocytosis, poikilocytosis, microcytosis and polychromatophilia. The liver function test showed total bilirubin of 29μmol/L (normal: 4–18), direct bilirubin of 6μmol/L (normal: 0–4). Serum ferritin level was 352ng/mL (normal: 20–200).

Chest radiography (Fig. 1) revealed widening of the upper mediastinum, large right paravertebral mass and paracardiac lobulated mass located at the posterior mediastinum. Computed tomographic scanning of the chest (Fig. 2) demonstrated two large, well circumscribed, paravertebral thoracic masses, measuring 6cm at the right and 8cm at the left, containing fat and associated with left pleural effusion. CT scan showed no adenopathy, or erosion of the vertebral bodies and the ribs. A CT-guided needle biopsy of the left mass was performed. Histological findings (Fig. 3) revealed normal hematopoietic tissue comprising erythroblasts, megakaryocytes and myeloid precursors without neoplasic infiltration.

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  • Figure. 2 

    Computed tomographic scanning of the chest: two large, well circumscribed, paravertebral thoracic masses, containing fat and associated with left pleural effusion.

As part of exploration of the anemia, a bone marrow aspirate was performed. It showed wealthy marrow with marked signs of dyserythropoiesis and nuclear fragility (bi and multinucleated cells) occurring in mature erythroid cells. Serum B12, folate and hemoglobin electrophoresis were normal. All these findings suggested the diagnosis of congenital dyserythropoietic anemia type II.

The final diagnosis of EMH presenting as posterior mediastinal masses in a patient with congenital dyserythropoietic anemia was established. Regular blood transfusions were performed.

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3. Comments 

EMH is a physiologic response to compensate for bone marrow dysfunction.2 It can occur in patients with either neoplasic process or chronic hemolytic anemia especially thalassemia, hereditary spherocytosis and sickle cell anemia.2, 3 It is rarely associated with congenital dyserythropoietic anemia; few cases are reported in the literature.4, 5, 6 Any site of the body can be involved by this phenomenon but the most common sites are the liver, spleen and lymph nodes.3 Less frequently locations include the kidneys, adrenal glands, intrathoracic cavity, presacral region, peritoneum, skin, breast, central nervous system and paravertebral areas.2, 3, 7

The pathogenesis of this outside-bone marrow hematopoiesis is unclear. It may originate from extension of hyperplastic marrow through the thin cortex of ribs and vertebral bodies; the capsule of the mass is formed by the periosteum. Another explanation is that EMH results from transforming of embryonal rests of osteogenic tissue into hematopoietic one under stress conditions in order to maintain sufficient red cell production.2, 8, 9

Intrathoracic EMH is most often silent, discovered by chance. In rare cases, it can compress neighboring organs and leads to clinical signs such as symptoms of spinal cord compression, dyspnea, cough or pleuritic chest pain.4, 7, 10 In our case, symptoms are due to the large size of the masses.

Radiographic exams are useful for recognizing the diagnosis. The chest X-ray shows smooth lobulated masses located at the posterior mediastinum without bony erosion.10, 11 On computed tomography scanning, intrathoracic EMH appears as unilateral or bilateral well circumscribed, paravertebral masses, lying between vertebra T6 and T12 and having soft tissue density with homogeneous contrast product's enhaussement. These masses contain sometimes adipose tissue as it was seen in our case; calcification is rare. Bony structures can be widened but not eroded in contrast to neurogenic tumors which are associated with osseous destruction in about 50 percent of cases.7, 9, 12 Technetium 99m-labeled sulfur colloid scan is also a noninvasive technique of detecting areas of EMH; this radioactive agent is taken up by reticulo-endothelial cells.3, 10

The diagnosis of EMH can be established on the basis of radiographic features especially when they occur in a patient with a long history of anemia. Although, if the diagnosis is not certain or if complications require surgical intervention, biopsy is mandatory.3, 10, 12 Histological proof can be obtained using transthoracic biopsy, video-assisted thoracoscopy or thoracotomy. All theses procedures should be carried out carefully because of the high risk of bleeding complications.8, 13

Treatment of EMH remains controversial and it is generally required only in the presence of complications such as spinal cord compression, massive hemothorax or recurrent pleural effusion. Low-dose radiation, repeated blood transfusions, surgery, corticosteroids and recently hydroxyurea therapy are the main therapeutic tools allowing the inhibition of hematopoiesis and the decrease of recurrence.3, 8, 10

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4. Conclusion 

Thoracic EMH represents a rare phenomenon complicating several chronic hemopathies. This diagnosis should be born in mind in front of posterior mediastinal masses in a patient with chronic hemolytic anemia in order to avoid dangerous surgical interventions.

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5. Conflict of interest statement 

We confirm that none of authors have a conflict of interest to declare in relation to this work.

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References 

  1. Lowman RM, Bloor CM, Newcomb AW. Roentgen manifestations of thoracic extramedullary hematopoiesis. Dis Chest. 1963;44:154–162
  2. Kugler D, Jager D, Barth J. A patient with pancreatitis, anemia and intrathoracic tumour. Eur Respir J. 2006;27:856–859
  3. Baser S, Fisekci FE, Ozkurt S, Kiter G, Kirac S, Alper H. A 26-yr-old female with persistent cough. Intrathoracic extramedullary hematopoiesis in a patient with beta-thalassemia intermedia. Eur Respir J. 2003;22:712–715
  4. Bowen EF, Marsh JC, Sandu C, Young M, Rayner CFJ. An elderly female with dyspnoea and anaemia. Eur Respir J. 2000;16:566–569
  5. mran A, Mawhinney R, Swirsky D, Hall C. Paravertebral extramedullary haemopoiesis occurring in a case of congenital dyserythropoietic anemia type II. Br J Haematol. 2008;140:1
  6. Hines GL. Paravertebral extramedullary hematopoiesis (as a posterior mediastinal tumor) associated with congenital dyserythropoietic anemia. J Thorac Cardiovasc Surg. 1993;106:760–761
  7. Bolaman Z, Polatli M, Cildag O, Kadiköylü G, Culbaci N. Intrathoracic extramedullary hematopoiesis resembling posterior mediastinal tumor. Am J Med. 2002;112:739–741
  8. Pornsuriyasak P, Suwatanapongched T, Wangsuppasawad N, Ngodngamthaweesuk M, Angchaisuksiri P. Massive hemothorax in a beta-thalassemic patient due to spontaneous rupture of extramedullary hematopoietic masses: diagnosis and successful treatment. Respir Care. 2006;51:272–276
  9. Smith PR, Manjoney DL, Teitcher JB, Choi KN, Braverman AS. Massive hemothorax due to intrathoracic extramedullary hematopoiesis in patient with thalassemia intermedia. Chest. 1988;94:658–660
  10. Nasr Ben Ammar C, Belaïd A, Kochbati L, Maalej M. Extramedullary haematopoiesis: report f two cases. Cancer Radiother. 2007;11:490–494
  11. Abe T, Yachi A, Ishi Y, et al. Thoracic extramedullary hematopoiesis associated with hereditary spherocytosis. Intern Med. 1992;31:1151–1154
  12. Alam R, Padmanabhan K, Rao H. Paravertebral mass in a patient with thalassemia intermedia. Chest. 1997;112:265–267
  13. Loh CK, Alcorta C, McElhinney J. Extramedullary hematopoiesis simulating posterior mediastinal tumors. Ann Thorac Surg. 1996;61:1003–1005

PII: S1755-0017(08)00112-7

doi:10.1016/j.rmedc.2008.12.010

Respiratory Medicine CME
Volume 2, Issue 3 , Pages 118-120, 2009

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