Table 4.

Comparison between type V IgG4-LAD and nodal inflammatory myofibroblastic tumor (IMT)

	Type V IgG4-LAD	Nodal IMT
Nature of lesion	An reactive inflammatory fibrosclerosing process	A neoplastic process in many cases
Symptoms	Usually no symptoms of fever, fatigue, weight loss, and night sweats	Usually with symptoms of fever, fatigue, weight loss, and night sweats
Clinical findings	Mass lesion, variable symptoms, often associated with systemic IgG4-RD	Mass lesion, not often with extranodal involvement
Gross features	Usually a poorly demarcated mass lesion	A discrete well-defined mass lesion
Histologic features	Fibrosclerotic lesion with poorly defined borders; patchy lymphoplasmacytic infiltration; mixed spindle fibroblasts and myofibroblasts	Well-demarcated lesion; evenly distributed lymphoplasmacytic cells; presence of abundant spindle tumor cells
IHC	No significant actin+ myofibroblasts; increased IgG4+ cells and IgG4/IgG ratios	Abundant actin+ cells; ALK+/-; no increased IgG4+ cells or IgG4/IgG ratio
Serum IgG4	Often elevated	Normal