Pheochromocytoma

  • Also known as: paraganglioma, chromaffinoma
  • Intra-adrenal sympathetic paraganglioma
  • Sporadic lesions: tend to be unilateral
  • Familial lesions: tend to be bilateral
  • 1.4-18% are incidentalomas
  • Co-exist with extra-adrenal paragangliomas (can also occur outside adrenal medulla)

Rule of 10

Pheochromocytoma associated genetic syndromes:

  • Multiple Endocrine Neoplasia (MEN) type 2
  • Von-Hippel-Lindau (VHL) syndrome
  • Neurofibromatosis (NF) type 1
  • Hereditary paraganglioma (PGL) syndromes – mitochondrial complex 2 gene

Pheochromocytomas may be the initial manifestation of these genetic syndromes.

Clinical features:

LION model (catecholamine excess)

  • palpitations
  • hypertension –> throbbing headaches
  • anxiety
  • chest pain
  • abdominal pain
  • sweat
  • breathlessness
  • 2ndary diabetes mellitus

Spells (episodes): variable, spontaneuous or precipitated by postural changes, anxiety, exercise, or increased abdominal pressure.

Macroscopic:

image

  • 3-5cm (may be up to 10cm)
  • Encapsulated
  • Cut surface: gray/white –> tan (on exposure to air)
  • Focal hemorrhage
  • Degenerative changes
  • Cystic
  • Calcification

Microcopic:

image

  • Alveolar (zellballen) / trabecular architecture / mixture
  • Pseudocapsule
  • Tumour cells resemble normal chromaffin cells
  • Cytoplasm: granular, basophilic/amphophilic
  • Nuclear & cytological pleomorphism (no prognostic significance)

Immunohistochemistry:

image

Chromogranin A +ve in all neuroendocrine tumours (not only in pheochromocytoma)

image

Synaptophysin +ve (neural origin)

Criteria for malignancy:

  • Presence of METASTASIS
  • If there is metastases, catecholamine excess is more obvious

_____________________________________________________________________

Extradrenal Paraganglioma

Pheochromocytoma occuring outside of the adrenal medulla, in ectopic sites.

  • Anywhere along parasympathetic/sympathetic chain
  • Histologically identical to the ones in adrenal medulla
  • Names by anatomical site
  • Common: Carotid body , jugulotypanic (chemodectoma), vagal paraganglioma
  • Only 1% clinically functioning
  • Potato tumour

image

image

LEAVE A REPLY

Please enter your comment!
Please enter your name here