The clinical manifestations of breast cancer mostly present as painless lumps in the breast. Many early-stage breast lumps are found during physical examinations or screenings. Lumps commonly develop in the upper outer quadrant and are typically solitary on one side, though occasionally there are multiple lumps, or they may appear bilaterally. The size of the clinically observed lumps varies, with diameters of up to 5 centimeters being common. Generally, the lumps are hard in consistency, have unclear boundaries, and are not easily movable within the breast. Sometimes, the nipple may be inverted and there may be bloody discharge. Enlarged lymph nodes may also be present under the armpit.