Extramedullary haematopoiesis in thalassaemia major causing spinal cord compression

Marrow outside marrow: imaging of extramedullary haematopoiesis

Extramedullary haematopoiesis (EMH) refers to the formation of non-neoplastic blood cell lines outside the bone marrow and is a common incidental finding when patients with haematological disorders are imaged. EMH presenting as mass (tumefactive EMH) has long been a radiological conundrum as it resembles neoplasms. Several imaging findings have been described in EMH, and these vary depending on the activity of the underlying haematopoiesis. The older lesions are easier to diagnose as they often demonstrate characteristic findings such as haemosiderin and fat deposition. In comparison, the newer, actively haematopoietic lesions often mimic neoplasms. Molecular imaging, particularly ^99mTc labelled sulphur colloid scintigraphy, may be helpful in such cases. Although imaging is extremely useful in detecting and characterising EMH, imaging alone is often non-diagnostic as no single mass shows all the typical findings. Hence, a judgement based on the clinical background, combination of imaging findings, and slow interval growth may be more appropriate and practical in making the correct diagnosis. In every case, an effort has to be made in providing an imaging-based diagnosis as it may prevent a potentially risky biopsy. When confident differentiation is not possible, biopsy has to be resorted to. This article describes the causes, pathophysiology, and theories underlying the genesis of EMH, followed by the general and location-specific imaging findings. The purpose is to provide a thorough understanding of the condition as well as enable the clinical radiologist in making an imaging-based diagnosis whenever possible and identify the situations where biopsy has to be performed.

Spinal epidural extramedullary haematopoiesis in β-thalassaemia intermedia

A 22-year-old man known to have β-thalassaemia intermedia since childhood presented with bilateral lower limb weakness after spinal anaesthesia for an elective minor operation of his left leg. MRI and CT scans were performed to rule out acute epidural haematoma; coincidental imaging features of marrow hyperplasia and spinal epidural extramedullary haematopoiesis were found. This article will present and discuss the imaging features, differential diagnosis, management and literature review of the rare occurrence of extramedullary haematopoiesis in the spinal epidural space.

Extramedullary hematopoiesis with spinal cord compression in a child with thalassemia intermedia

Spinal cord compression due to extramedullary hematopoiesis is an extremely rare complication of thalassemia intermedia. No cases with this complication have been reported in the first decade of life, because masses of heterotropic marrow developed in patients as a result of continuous erythropoiesis. We report the 9-year-old patient suffering from thalassemia intermedia and presenting spinal cord compression. We also review the literature about treatment options, because there is no consensus about the optimal treatment of these patients. Our patient was successfully treated with radiation therapy followed by hydroxyurea. With this combination therapy, he had no recurrence during the 4-year follow-up period. Clinical awareness of this phenomenon with the early treatment is essential for optimizing the successful outcome.

Extramedullary hematopoiesis: findings on computed tomography scans of the chest in 6 patients

OBJECTIVE

To present findings on computed tomography scans of the chest indicative of extramedullary hematopoiesis in six patients.

METHODS

We retrospectively analyzed computed tomography scans of six adult patients - five males and one female - with a mean age of 36.5 years. Two radiologists independently reviewed the scans, and a consensus was reached in discrepant cases.

RESULTS

The most common finding in the scans was lower paravertebral masses with heterogeneous content (four patients). The scans of two patients showed a solitary parietal and pleural mass.

CONCLUSIONS

There are findings in computed tomography scans that are highly suggestive of extramedullary hematopoiesis, especially when those findings correlate with underlying blood diseases. Such findings, in most of the cases, allow physicians to dispense with histopathological confirmation.