New Proposed Criteria for Diagnosis of Nephrogenic Systemic Fibrosis

Cowper and colleagues have proposed a new system "to guide and standardize the evaluation and diagnosis of nephrogenic systemic fibrosis." In contrast to the old Cowper criteria, this is a scoring system that uses clinical and histopathological features to yield two scores: a clinical score and a histologic score. The combination is used to give the clinician an idea of how strongly nephrogenic systemic fibrosis should be suspected. Like the old system, there is no role for radiology in the diagnosis, but it's good to know how our colleagues in dermatology and pathology will be diagnosing one of the complications associated with our practice.

Major clinical criteria:

• Patterned plaques: Red to violaceous thin, fixed skin plaques showing polygonal, reticular, or "amoeboid" morphologies.
• Joint contractures:
• Cobblestoning:
• Marked induration/Peau d'orange: Unpinchable, firm, bound-down skin over the extremities. Peau d'orange refers to follicular dimpling. Must be present in the upper extremity or in the lower extremity above the knee.

Minor clinical criteria:

• Puckering/linear banding:
• Superficial plaque/patch: Thin, irregularly bordered hypopigmented, pink, or flesh-colored macules coalescing into patches or thin plaques. Common on the upper extremities and unusual on the trunk.
• Dermal papules: Slightly brawny papules without epidermal changes.
• Scleral plaques: There are new-onset white/yellow scleral plaques with dilated capillary loops in a patient younger than 45 years.

Clinical scenario	Clinical score
> 1 major criteria	4
1 major criterion	3
≥ 1 minor criteria	2
1 or no minor criteria	1
Diagnostic of another entity	0

Histologic findings:

• Increased dermal cellularity: Increased numbers of spindled and/or epithelioid cells with few other inflammatory cells in the dermis. (Histologic score +1).
• CD34+ cells with tram-tracking: CD34+ spindle or epithelioid cells in a reticular or parallel arrangement forming a complex network. (Histologic score +1).
• Thick and thin collagen bundles: Both fine and ropey collagen surrounded by clefts. (Histologic score +1).
• Preserved elastic fibers : Use elastic stain to assess elastic content. (Histologic score –1 if absent, otherwise unchanged).
• Septal involvement : Expansion of interlobular septa by collagen, cells, and other matrix elements. Spindle cells encroach on fat lobules. (Histologic score +1).
• Osseous metaplasia: A highly specific feature. Nonmineralized osseous tissue around elastic fibers, some of which protrude beyond the zone of ossification. (Histologic score +3).

Histologic	Clinical score
score	0	1	2	3	4
0		Consider alternative diagnosis
1			Not NSF		Inconsistent
2			Suggestive	Consistent
3			Consistent	NSF
4		Inconsistent

References

Girardi M, Kay J, Elston DM, Leboit PE, Abu-Alfa A, Cowper SE. Nephrogenic systemic fibrosis: Clinicopathological definition and workup recommendations. J Am Acad Dermatol. 2011 Jul 1. [Epub ahead of print]