Serous atrophy of bone marrow
Serous atrophy of bone marrow is a non-neoplastic bone marrow disorder that occurs with chronic illness and poor nutritional status. It is characterized by atrophy of the fatty marrow and loss of hematopoietic cells, replaced by an accumulation of extracellular mucinous substances.
Terminology
Serous atrophy of bone marrow is the preferred term for this disorder, which has also been termed gelatinous marrow transformation .
Clinical presentation
Patients can develop osteoporosis and may present with insufficiency fractures.
Pathology
Serous atrophy can be evident in:
- cachexia
- anorexia nervosa or other eating disorders
- AIDS
- alcohol excess
- acute febrile illness
- malignancies
- chronic renal failure
- congestive heart failure
- myelodysplastic syndrome
Radiographic features
Radiographs
- severe soft tissue wasting
CT
- subcutaneous and visceral fat are nearly absent
MRI
MRI shows striking changes in the fat. Fluid intensity regions in the marrow that are initially patchy but become confluent. These progress in the same order as red to yellow marrow conversion: distal extremities to proximal extremities and axial skeleton. Similar signal abnormalities can usually be observed in the adjacent subcutaneous fat .
- T1: mildly low signal intensity
- STIR: high signal intensity
- T1 C+ (Gd): non-enhancing bone marrow
Practical points
- knowledge of this condition is important so as not to subject the patient to a repeat MRI out of concern that the study is technically faulty
- visceral and subcutaneous fat are nearly absent, which should alert the interpreter to the condition
- serous marrow does not enhance, differentiating from a diffuse infiltrating malignancy which will enhance after contrast administration
- serous marrow is often associated with insufficiency fractures, which may be obscured on MRI by the abnormal bone marrow signal
- CT can be used as a problem-solving tool to further assess for an insufficiency fracture that cannot be visualized on MRI