Adrenal gland

Adrenal gland is a little organ that hangs-out above the kidney. Pathologists rarely see it. It uncommonly is affected by tumours.

Anatomy & histology

Histology

Composed for cortex and medulla.

• Cortex has three layers - Mnemonic: GFR (from superficial to deep):
  • Zona glomerulosa - salt (e.g. aldosterone)
    • eosinophilic cytoplasm???
    • Normally discontinuous layer.
  • Zona fasciculata - sugar (e.g. cortisol)
    • Clear cytoplasm - key feature.
    • Largest part of the cortex ~ 70%.
    • Cells in cords/nests???
  • Zona reticularis - steroid (e.g. dehydroepiandrosterone).
    • Marked eosinophilia of cytoplasm - key feature.
    • Granular/reticular cytoplasm.
• Medulla - produces NED: norepinephrine, epinephrine, dopamine.

Clinical

Patients getting a bilat. adrenalectomy get pre-treatment with steroids.

Adrenal insuff. may be immediately post-op.

Benign

• Spironolactone bodies.
  • Location: zona glomerulosa (where aldosterone is produced).
  • Appearance: eosinophilic spherical laminated whorls.
  • Etiology: long-term use of spironolactone.

Adenomas

Radiology

• Radiologists are good at identifying adenomas, as they are usually lipid rich and have a characteristic low HU signal.

Treatment is excision if...

• Lesions >30 mm.
• Hormonally active.
• Non-incidental finding. (???)

Hyperplasia vs. adenoma

• Hyperplasia is multifocal.

Adrenal cortical adenoma

Epidemiology

• Often an incidental finding.

Pathologic/clinical:

• May be hormonally active.

Histology

Classic features:

• Well-defined cell borders.
• Clear cytoplasm.
• May have foci of necrosis/degeneration and nuclear atypia.

In aldosterone producing tumours:

• May extend outside of the capsule (should not be diagnosed as adrenal cortical carcinoma.
• No atrophy of non-hyperplastic cortex.

In cortisol producing tumours:

• Atrophy of the non-hyperplastic cortex (due to feedback inhibition from the pituitary gland).

Pheochromocytoma

General

• Considered to be a paraganglioma.

Clinical

• Paroxysms (i.e. episodic) tachycardia, headache, anxiety.

Epidemiology

• Tumour arises from medulla
• Literally means "dusky" (pheo) "colour" (chromo) - dull appearance on gross

Histology

Features:

• Architecture:
  • Cell nests, auf deutsch: Zellballen (literally Cell balls).
    • Useful for differentiating from ACC.
• Nuclei.
  • +/-Pleomorphism.
  • Nucleoli may be prominent (not signif. prognostically).
• Cellular morphology.
  • Polygonal cells.
• Cytoplasm.
  • Basophilic, granular.
• Other.
  • Haemorrhagic.

Ganglioneuroma

Microscopic

Features:

• Ganglion cells - key feature.
  • Large cells with large nucleus.
    • Prominent nucleolus.
• Disordered fibrinous material.

Adenomatoid tumour

See: Adenomatoid tumours (uterine tumours).

Adrenocortical carcinoma (ACC)

Epidemiology:

• Prognosis sucks.

Microscopic

Features:

• Very pleomorphic nuclei.
• High mitotic rate.
• Atypical mitoses.
• Eosinophilic cytoplasm.

Malignant pheochromoctyoma

• Like the description in benign neoplasms.
• Differentiated from benign pheochromocytoma by mets - often aided by radiologic report.
• Features useful for differentiating benign from malignant:
  • Marked nuclear atypia.
  • Invasion:
    • Capsular.
    • Vascular.
  • Necrosis.
  • Cellular monotony.
  • Mitoses:
    • Rate.
    • Atypical mitosis.

Neuroblastoma

Epidemiology

• Usually paediatric population.

Microscopic

Features:

• See: Small round cell tumours.