This low magnification view lends perspective to the extent of bone marrow involvement and demonstrates two distinct infiltrative patterns. In addition to the common type, several ALCL variants have been identified. These include the small-cell and lymphohistiocytic sub-types, as well as other patterns not designated as official variants, such as the giant cell-rich, sarcomatoid, and signet ring cell-rich patterns. Up to 10% of ALCL tumors demonstrate more than one histological variant. This image reveals sheets of malignant cells infiltrating the marrow on the left, which develop into a dense region of sarcomatoid-like growth on the right, comprised of cells of characteristic morphology mingling with spindled cells.