Case 52 - Discussion

Uploaded: 2007-06-02, Updated: 2007-12-27

 

ADRENAL CORTICAL ADENOMA

 

The Key Features

  • Unilateral, solitary, well-demarcated, benign;

  • Compared with cortical carcinoma: <100  grams, limited atypia or mitoses, no necrosis.

 

CLINICAL FEATURES

  • Typically unilateral, solitary, benign;

  • Endocrine abnormality: primary hyperaldosteronism > Cushing's syndrome > virilization and occasional feminization;

  • Image studies: well-defined, smooth contour, and homogeneous.

GROSS FINDINGS

  • Solitary, unilateral and unicentric;

  • Often < 50 grams;

  • Sharply circumscribed or encapsulated;

  • Cut surface: homogeneously yellow or golden-yellow, or with foci of dark discoloration (hemorrhage or lipid depletion);

  • Black adenoma: diffusely dark brown.

MICROSCOPIC FINDINGS

  • Often have relatively smooth pushing border without a well-defined fibrous capsule;

  • Usually have broad fields of pale-staining, lipid-rich cells with relatively uniform nuclei and clear cytoplasm;

  • Architectures: nests, alveolar, short cord, narrow interconnecting trabeculae, or a mixture of these patterns;

  • Cytology: compared with the normal cortical cells, the tumor cells are usually larger with different quality of cytoplasm and variation in nuclear size and configuration; tumor cells have abundant pale-staining, lipid-rich cytoplasm and relatively distinct cell borders; lipid-depleted or poor cells have eosinophilic cytoplasm and sometimes conspicuous lipochrome pigment;

  • Tumor cell nuclei are usually single and round to oval, vesicular; may have moderate nuclear enlargement and hyperchromasia;

  • Rare mitotic figures;

  • Other features: occasional foci of diversity of cytological features, balloon cells, or spindle cells; lipomatous, myelipomatous or bony metaplasia;

  • Adrenal remnant may show cortical atrophy in association with Cushing's syndrome.

SUBTYPES

  • Black (pigmented) adenoma: similar architectures but composed of predominantly tumor cells with compact, eosinophilic cytoplasm and variable amounts of brown or golden brown cytoplasmic pigments;

  • Cortical adenoma with Conn's syndrome: usually smaller than with Cushing's syndrome, hyperplasia of Zona Glomerulosa, spironolactone bodies (in zona glomerulosa, small, 2-12 um,  round to oval intracytoplasmic inclusions, lightly eosinophilic, with a laminated, scroll-like appearance, often demarcated from surrounding cytoplasm by a small clear halo);

  • Oncocytic adrenal cortical adenoma: abundant mitochondria.

DIFFERENTIAL DIAGNOSES

  • Adrenal cortical carcinoma: larger (>100 grams), more atypia, necrosis and mitoses,

ELECTRON MICROSCOPIC FINDINGS

  • Abundant cytoplasmic lipid droplets in variable sizes and densities from cell to cell.

REFERENCES

  • AFIP, tumor of the adrenal glands and extra-adrenal paraganglia, series 3;