Urinalysis Case Study - Dysmorphic RBCs

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What are Dysmorphic RBCs?

Red blood cells, also known as erythrocytes, can sometimes be present in the urinary tract. It may be normal to see small amounts of RBCs in urine; however, gross hematuria may indicate a more serious condition such as malignancy, injury or infection.

Dysmorphic RBCs are red cells that that develop cytoplasmic bulges as a result of glomerular bleeding in patients with intrinsic renal disease. Recognition of dysmorphic red cells during examination of urine sediment is critical because their presence is likely an indication of renal pathology.

Morphologically, dysmorphic RBCs may be slightly smaller than isomorphic (“normal” appearing or “nonglomerular”) red cells and have apparent cytoplasmic bulges or “blebs” that may separate from the cell and appear as red cell fragments. It is important not to confuse dysmorphic red cells with budding yeast forms.

Morphology/Features:

• Round, often hemoglobin-filled cells with cytoplasmic blebs
• Sometimes called “Mickey Mouse” cells because oftentimes cells have two symmetrical and opposing projections

 

Resources:
Color Atlas of the Urinary Sediment, College of American Pathologists, Northfield, IL.
Atlas of Urinary Sediment, Sysmex Corporation, Kobe, Japan.

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