Malicious Tumor? Pathological Fracture of the Femur in Children Caused by Myelolipoma: A Case Report and Review of Literatures

Table 1

Differential diagnosis of intraosseous lipoma.

Disease	Symptoms or signs	Imaging features	Pathologic findings
Adrenal myelolipoma and extra-adrenal myelolipoma	Asymptomatic, compression, and hemorrhage due to mass effect	Well-defined lesions with variable amounts of fat signals interspersed with high-density, intensifiable myeloid components	Normal adipose tissue and hematopoietic tissue
Intraosseous myelolipoma	Asymptomatic or associated with chronic pain, rarely pathological fractures	Intramedullary lytic lesions without cortical expansion, signal intensity similar to adrenal myelolipoma, and irregular sclerosis may be present	Normal adipose tissue and hematopoietic tissue
Localized osseous hematopoiesis	Asymptomatic or compression due to mass effect	Well-defined, expanded, lytic masses with linear high-density areas and calcifications	Normal bone marrow tissue
Intraosseous lipoma	Asymptomatic, chronic pain, and occasional pathological fractures	Local density similar to normal fat, well-defined borders, trabecular bone resorption, possible calcifications within the cavity, sparing the bone cortex, and no periosteal reaction	Normal adipose tissue and no hematopoietic tissue
Fibrous dysplasia of bone	Limb swelling, deformity, pathological fractures, and pain	Variable imaging features, mostly expansive lesions; bone enlargement or thickening; bending deformities of the affected long bones; thinned but intact cortex; and no periosteal reaction. Ground-glass or loofah-like changes	Abnormal proliferating fibrous tissue and immature trabecular bone
Waxy bone disease	Limb pain, bone and joint deformities, limited range of motion, and palpable irregularity of the bone surface	Imaging shows proliferative bone along the long axis of the bone, resembling a waxy appearance	Mixed composition of laminar and woven bone