Journal de radiologie OMICS

Abstrait

A Typical Extramedullary Haematopoiesis in a JAK2 Mutated Primary Myelofibrosis Patient after a Minor Head Injury

Vadsala Baskaran, Cho Wai Sum, Mansoor Aslam, Alfredo Addeo and Ciro Roberto Rinaldi

Intracranial extramedullary haematopoiesis (EMH) is very rare. We report the case of EMH with intracranial involvement which developed after trauma in a 73-year-old lady affected by JAK2 mutated myelofibrosis (MF). She was diagnosed with MF in 2005 and treated with low-dose-steroids (prednisolone and oxymethalone) for about 5 years with anexcellent response on full blood count and splenomegaly.
In June 2011, she fell from the stairs and sustained minor trauma to the forehead. Six weeks later, the patient had a gradually enlarging and moderately painful lump in the centre of her forehead. A contrast-enhanced CT scan of the head was performed, showing a small fracture in the frontal bone infiltrated and surrounded by a soft tissue mass extending intracranially and invading the skin extracranially (Figures 1 and 2). A metastatic deposit from an occult tumour was suspected.
In August 2011, we performed a CT-guided trucut biopsy of the forehead mass. The histology report confirmed extramedullary haematopoiesis according to the patchy expression of myeloid (CD45, CD43, myeloperoxidase) and megakaryocytic markers (CD68, CD42b). We concluded that the trauma caused a small fracture which triggered the bone marrow tissue reaction resulting in production of extramedullary haematopoiesis in the site of the trauma. The patient underwent local radiotherapy resulting in complete resolution of the lesion.