Gross: usually solitary lesions, well encapsulated, cut surface is yellow-tan (or black, for black adenomas); by definition, adenomas generally measure < 5 cm and weigh < 50 g.
Histology:
recapitulate the zona glomerulosa and zona fasciculata
bizarre nuclei may be seen but mitoses are exceptionally rare or absent
may contain foci of myelolipoma, manifested by the presence of bone marrow elements
Variations on the theme:
Aldosterone-omas: golden yellow color with targetoid “spironolactone” bodies
Black adenomas: have dark brown/ black color due to the presence of lipofuscin pigment; may be associated with primary aldosteronism or Cushing’s syndrome
Adrenocortical oncocytomas: highly eosinophilic cytoplasm due to numerous mitochondria.
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