Type 2: Insulin resistance and inadequate secretion
Etiology/Pathogenesis
• Unknown and multifactorial
Possible autoimmune causes
Some genetic causes
Diseases of exocrine pancreas
Clinical Issues
• Laboratory tests
Elevated random plasma and fasting glucose, hemoglobin A1c
Macroscopic
• Decreased size and weight (type 1 > type 2)
Microscopic
• Type 1
Variation in islet size and shape with irregularly shaped islets
Reduced or absent B cells
Variably present islet inflammation
Amyloidosis almost never seen in type 1 diabetes
• Type 2
Islet amyloidosis
Reduction in both A and B cells
Islets reduced in number but unchanged in size
• Both types
Interlobular and interacinar fibrosis, exocrine atrophy
Exocrine atrophy
Top Differential Diagnoses
• Normal aging may also result in decreased size and weight of pancreas, islet amyloidosis
Fibrosis and Variably Sized Islets This section from the pancreas of a patient with diabetes shows variably sized islets with focal amyloid deposition and increased interacinar fibrosis.
Islet With Amyloid Dense nodules of amyloid are seen within an islet in this case of type 2 diabetes.
Fatty Infiltration Fatty infiltration may also be a feature of diabetes seen in the pancreas, especially in type 2 diabetes. Note the central islet with amyloid deposition.
Islet Replacement by Amyloid This islet is almost completely replaced by amyloid. There is also fatty infiltration of the pancreas.
TERMINOLOGY
Abbreviations
• Diabetes mellitus (DM)
Definitions
• Heterogeneous group of metabolic diseases characterized by hyperglycemia
Result of defects in insulin secretion, insulin activity, or both
• General classification
Type 1
– Absolute insulin deficiency
Only gold members can continue reading. Log In or Register to continue
and increased interacinar fibrosis.
