Extranodal Marginal Zone B Cell Lymphoma

Clinical

Mean age 60 years, rare before 30
- Immunnoproliferative small intestinal disease variant usually young adults
Generally involves epithelial organs or sites
- Head and neck
  - Salivary gland
  - Thyroid
  - Pharynx
  - Conjunctiva and lacrimal gland
    - Associated with Chlamydia species
      - Geographic variation in incidence reported
- Gastrointestinal tract
  - Stomach
  - Intestines
- Urinary tract
  - Bladder
  - Kidney
- Skin
- Breast
Frequently remains localized to an extranodal site
Recurrences frequently extranodal
Frequent clinical associations, depending upon location
- Sjogren syndrome (salivary and lacrimal gland)
  - About 5% develop lymphoma
- Hashimoto disease (thyroid)
  - About 1% develop lymphoma
- Helicobacter pylori infection (stomach)
  - Eradication of Helicobacter can lead to remission
  - Cases that persist after anti-Helicobacter therapy may harbor specific translocations
Overall prognosis excellent
- Indolent and slow to disseminate
- No worsening of prognosis with dissemination
- No worsening of prognosis with follicular colonization, even if by large cells
- At some sites, cure by excision has been reported
- Worse prognosis following transformation
Incidence
- Marginal zone lymphomas of all types make up approximately 8% of lymphomas
- 50% of gastric lymphomas
Geographic distribution
- Gastric marginal zone lymphoma is increased in northern Italy
- Immunoproliferative small intestinal disease is most common in Mediterranean zone and South Africa