If, alas, the process grows more rapidly still, then the bone's retreat may become disorderly indeed. Continuing this battlefield analogy, the boundary between normal and abnormal bone may be lost altogether, with only a very ill-defined pattern of lucency seen, caused by many small, irregular holes in the bone, left behind by osteoclasts. The presence of a permeative pattern usually means that the patient either has an aggressive infection or a malignant tumor. The most common malignancies that give this pattern are metastases, myeloma, primary histiocytic lymphoma, and Ewing's sarcoma. It is stuff produced by osteoblasts and chondroblasts that eventually becomes, respectively, normal bone and cartilage.
Bone tumors form matrix just as a normal bone does, but sometimes in greater quantity.
Also, matrix produced by tumors is usually quite abnormal, and does not ossify properly. In order to see matrix on plain radiographs, it has to calcify. Chondroid matrix, for example tends to produce small punctate or swirled areas of calcification. If I don't see any definite calcified matrix in a lesion, I prefer to just say that instead. Location Most expansile, lucent lesions are located in the medullary space of the bone.