sections revealed a lobular proliferation of mature hyaline cartilage situated within a fibrofatty background. The cartilaginous lobules are composed of bland, uniform chondrocytes residing within regular lacunae, lacking significant cytologic atypia, significant nuclear pleomorphism, binucleation, or mitotic activity. Widespread secondary changes are present throughout the lesion, characterized by prominent areas of deep basophilic calcification and mature endochondral ossification. There is no evidence of hypercellularity, myxoid degeneration, or malignant infiltrative growth.
Calcified infrapatellar fat pad lesion with a differential diagnosis of an infrapatellar soft tissue chondroma.
One soft tissue and bone fragment measuring 4.8 x 4 x 2.3 cm, which upon sectioning revealed an almost bony, somewhat firm, and grey-colored appearance.
Soft tissue, knee, excision: