CRP-41

CRP-41

Clinical History

The patient is a 53 year old male who has had diabetes for many years. He also has multiple myeloma with associated renal insufficiency and anemia.

Gross Description

Received in Zeus fixative are two cores that each measure 12 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are two cores each measuring 16 mm in length and l mm in diameter. Three 1-mm pieces are taken for EM and the remainder is submitted for light microscopy.

Pathology

Case CRP-041 Trichrome

Microscopic Description, Immunofluorescence, and Electron Microscopy.

Microscopic Description

Light Microscopy

The specimen consists of two long fragments of renal cortex with small portions of medulla. There are sixty-six glomeruli in the three levels. Thirty-one of these are obsolete, and many of the remaining glomeruli show segmental sclerosis and focal hyalinosis. All of the glomeruli show nodular and diffuse intracapillary sclerosis, and several distinct Kimmelstiel-Wilson nodules are identified. The capillary basement membranes are generally quite thick with the PASH and silver stains, although no spike formation or splitting are identified. There is severe diffuse interstitial fibrosis with corresponding tubular atrophy. The tubules generally show markedly thickened basement membranes, which arc also split and generally wrinkled. There are occasional mononuclear inflammatory cells throughout the fibrotic interstitium, but there is no tubulitis. There are no casts with the characteristic appearance of light chain casts. The arterioles and small arteries show moderate intimal thickening, but the vascular injury is less than one might expect for this degree of glomerulosclerosis and interstitial fibrosis. A Congo red stain is negative in the glomeruli and vessels with an adequate positive control.

Immunofluorescence

There are fifteen glomeruli in the sections. There is 2+ focal and segmental mesangial staining for IgM, C1q and C3. There is no glomerular staining for IgG, IgA or light chains. Tubular basement membranes show 2+ linear staining for IgG and albumin. There is no staining for kappa or lambda light chain in the tubular basement membranes. There is no staining of the vessels.

Electron Microscopy

Three thick sections containing a total of two glomeruli are available. These are similar and show diffuse intercapillary glomerular sclerosis and global atrophy. Tubular basement membranes show marked thickening as described above. Ultrastructural examination reveals diffuse uniform thickening of the capillary basement membranes. These basement membranes are generally about three to four times the normal thickness. There is diffuse fusion of the epithelial cell foot processes. Mesangial matrix is markedly increased. However, no immune complexes deposits or fibrillary deposits are identified in the glomeruli or tubular basement membranes.

Diagnosis and Comments

Kidney, needle biopsy - Diabetic nephropathy, severe.

These findings are most consistent with advanced diabetic nephropathy. Since the patient has a history of multiple myeloma, the biopsy was carefully examined for amyloidosis or some other type of light chain related disease. However, there is no evidence in this biopsy for amyloidosis, light chain cast nephropathy or light chain deposition disease. The marked degree of glomerulosclerosis and interstitial scarring is consistent with an extremely poor prognosis for this kidney.

Aortic insufficiency refers to the inability of the aortic valve to close properly, thus allowing regurgitation of blood into the left ventricle during diastole -- i.e., volume overload. Disease of the aortic valve leaflets is a common cause of insufficiency.

Nodular hyperplasia of the prostate--characterized by large discrete prostatic nodules--is a common disorder in men over 50 years of age. The nodules cause the prostate to be enlarged and to have an increased weight. The human prostate is surrounded by a restrictive capsule. These nodules cause increased pressure within the capsule which leads to constriction of the urethra as it passes through the prostate. Urethral constriction leads to retention of urine.