Age / Sex : 62 / F

Cortical Metastasis

Discussion

Findings:

Radiography – Avulsion facture of the lesser trochanter with suspiciously osteolytic lesion

MRI – An expansile soft tissue mass at the lesser trochanter of the left femur, which shows heterogeneous enhancement on postcontrast images. The epicenter of the tumor is the cortex of the lesser trochanter and subcortical medullary extension of the tumor is also noted.
 

Differential Diagnosis:

Metastasis, plasmacytoma, lymphoma
 

Diagnosis: Cortical Metastasis from Lung Cancer  
 

Discussion:

The common origins of the cortical metastases included lung, breast and kidney. The lesions commonly occur in the tibia and femur. Cortical metastasis are categorized into 4 types; metastasis confined to the cortex (type 1), extension into the soft tissue (type 2), extension into the marrow cavity (type 3), and predominantly subperiosteal location (type 4).

When avulsion fracture of the lesser trochanters is seen in the adult without significant trauma, it should be regarded as secondary to metastatic neoplasm until proven otherwise.
 

References:

1. Hendrix RW, Rogers LF, Davis TM. Cortical bone metastases. Radiology 1991;181:409-413


2. Coerkamp EG, Kroon HM. Cortical bone metastases. Radiology 1988;169:525-528


3. Phillips CD, Pope TL Jr, Jones JE, Keats TE, MacMillan RH 3rd. Nontraumatic avulsion of the lesser trochanter: a pathognomonic sign of metastatic disease? Skeletal Radiol1988;17:106-110


4. Bui-Mansfield LT, Chew FS, Lenchik L, Kline MJ, Boles CA. Nontraumatic avulsions of the pelvis.AJR 2002;178:423–427