Mediastinum
Other benign / low grade tumors
Paraganglioma

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 18 June 2018, last major update December 2012

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Paraganglioma[TI] mediastinum

Cite this page: Gulwani, H. Paraganglioma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumparaganglioma.html. Accessed September 21st, 2018.
Definition / general
  • Rare, 0.3% of mediastinal tumors
Epidemiology
  • Usually young women
Sites
  • Aorticopulmonary vascular root (anterosuperior mediastinum) or paravertebral (posterior mediastinum)

Aorticopulmonary:
  • Mean 49 years old, no gender preference, 3% synthesize catecholamines
  • May be fatal if extensive local invasion

Paravertebral:
  • Mean 29 years old, usually men, 50% synthesize catecholamines
  • Only rarely cause death
Clinical features
  • Associated with MEN2 syndrome
  • Also associated with Carney triad of pulmonary hamartomas, malignant gastrointestinal stromal tumors, extraadrenal paragangliomas
Diagnosis
Catecholamine secreting tumors:
  • Present with symptoms of pheochromocytoma, usually hypertension (abrupt; with tachycardia, palpitations, headaches, tremor, sense of apprehension, unresponsive to treatment; isolated paroxysmal episodes of hypertension in < 50%)
  • Triad of sweating attacks, tachycardia and headaches is relatively specific

Catecholamine cardiomyopathy:
  • Myocardial instability, ventricular arrhythmias
  • Due to ischemic damage from vasoconstriction of coronaries or direct toxicity
  • Myocytolysis, interstitial fibrosis, mononuclear inflammation

Diagnosis for catecholamine secreting tumors:
  • Increased urinary excretion of catecholamines or metabolites (vanillylmandelic acid [VMA] or metanephrines)
  • Elevated chromogranin A serum levels
Prognostic factors
Poor prognostic features:
  • Invasion into contiguous soft tissue
  • Also combination of confluent tumor necrosis, coarse tumor nodularity and lack of globular cytoplasmic inclusions
Case reports
Gross description
  • Firm, red-pink-brown
  • Hemorrhage and necrosis common
  • Partial or no capsule
Gross images

Images hosted on other servers:

Various tumors

Microscopic (histologic) description
  • Tumor cells grow in tight nests of similar size (Zellballen), surrounded by fibrovascular stroma
  • Cytoplasm is granular, eosinophilic or amphophilic; hyaline globules may be present
  • Nuclei are round, fusiform or pleomorphic
  • Chromatin may be dense or vesicular
  • Usually no / scant mitotic figures
  • Occasionally contain melanin
Microscopic (histologic) images

Images hosted on other servers:

Various images

Positive stains
Negative stains
Electron microscopy description
  • Pleomorphic secretory granules if secrete norepinephrine
  • Nondescript endocrine granules in nonsecretors
  • No intermediate filament whorls, no tonofibrils, no microvilli
Molecular / cytogenetics description
  • RET proto-oncogene mutations in exons 10, 11, 13, 15, 16 in 15%