Geographic destruction of bone is characteristic • Skull: a bevelled edge to the defect, indicating destruction of the two tables to a differing degree (‘hole within a hole’ sign) • Paediatric spine: thoracic > lumbar > cervical involvement • Flat or long bones: typically diaphyseal involvement with an ill-defined medullary lesion • Unusual features: epiphyseal lesions • The most common lipid storage disorder due to an autosomal recessive genetic enzyme (glucocerebrosidase) deficiency • Infantile form: hepatosplenomegaly, lymphadenopathy, neurological complications, anaemia and haemorrhage • Adult form: hepatosplenomegaly, abdominal pain, ascites, dull bone pain or acute painful crises due to bone infarction (± fever, leucocytosis and a raised ESR) • Cancer of the blood-forming cells of the bone marrow (usually affecting leucocytes)
Myeloproliferative disorders
RETICULOENDOTHELIAL DISORDERS
LANGERHANS CELL HISTIOCYTOSIS
DEFINITION
RADIOLOGICAL FEATURES
Eosinophilic granuloma
XR
lesions of the hands and feet are rare
it classically causes a vertebra plana, with the vertebral body becoming flattened and often wafer-thin
endosteal erosion and a linear periosteal reaction is common
transphyseal lesions 
extracranial ‘button’ sequestra 
posterior vertebral arch lesions
GAUCHER’S DISEASE
DEFINITION
this leads to accumulation of the lipid glucocerebroside within the lysosomes of monocytes and macrophages of many organs (Gaucher cells)
death usually occurs at < 2 years of age (mainly due to CNS involvement) 
it mainly affects non-Jews
many patients are Ashkenazi Jews
WHITE CELL DISORDERS
LEUKAEMIA
DEFINITION
Acute lymphocytic leukaemia (ALL): this affects adults and children although it is more common in children (65% of paediatric acute leukemias)
Acute myeloblastic leukaemia (AML): the most common adult acute leukemia
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
Myeloproliferative disorders
it affects children < 2 years of age 
splenomegaly, hepatomegaly and lymphadenopathy with anaemia predominate (patients usually die before any bone lesions are identified) 
patients present with fever and a failure to thrive
a classical triad of calvarial lesions + exophthalmos (due to bony orbit histiocytosis) + diabetes insipidus
benign and self-limiting 
80% present before 10 years of age (2M:1F) 
multiple lesions in 10% at presentation 
pain and local tenderness (± a moderately elevated ESR) 
pathological fractures are rare
long bone metaphyseal and diaphyseal lesions are initially lytic but later heal with periosteal reaction and medullary sclerosis 
pelvic and vertebral body lesions are common
T1WI: low SI 
T2WI/STIR: high SI 
extraosseous involvement in 30%
an Erlenmeyer flask deformity (due to loss of normal modelling) 
osteosclerosis (due to a healing bone infarct) 
metaphyseal notching of the humerus (secondary to increased bone turnover) is characteristic
T1WI: low SI 
T2WI: high SI
periosteal reaction
possible cord compression
it resembles Gaucher’s disease but there is deposition of sphingomyelin within foam cells
twice as common as CML 
characterized by enlargement of the spleen and lymph nodes and rarely skeletal involvement (except as a terminal event)
