Oral Medicine & Pathology

Non-Hodgkin’s Lymphoma: Imaging , clinical findings , pathology , treatment , epidemiology

 

 

Non-Hodgkin’s Lymphoma      

 

Epidemiology

  •  There are two basic categories of lymphoma: Hodgkin’s disease (HD) and non-Hodgkin’s lymphoma (NHL).
  • Together they account for approximately 3 to 5% of all newly diagnosed malignancies and deaths in developed countries.
  • NHL is more common than HD and represents 60 to 70% of all lymphomas.
  • These tumors affect all age groups.
  • The distribution is, however, bimodal with a peak in young adulthood followed by a plateau III middle age and a steep rise in old age.

 

Clinical Findings

  •   N HL can present either with lymph node enlargement, an extranodal mass, or both.
  • Patients with masticator space NHL may have trismus or pain that may be associated with or without cervical lymphadenopathy.
  • The incidence of systemic signs such as fever is 1 0 to 1 5%.

Pathology

  • Histologic classification of NHL is notoriously difficult but newer techniques for classification such as immunologic phenotyping, nucleic acid analysis with flow cytometry, and molecular genetics may help to explain the apparent diversity of morphological appearances.
  • One of the most popular classifications is the Rappaport system, which is based on pattern of involvement and cellular appearance.
  • In general, nodular lymphomas have a more indolent course compared with the diffuse variety.
  • HD is almost always confined to lymph nodes, whereas 40 to 60% of NHL present have extranodal involvement.
  •  Approximately, one third to two thirds of extranodal involvement is found in the head and neck.
  • The most common head and neck sites are the orbits and Waldeyer’s ring. Masticator space NHL is rare.

Treatment

  •   For treatment purposes, NHL is divided into favorable and nonfavorable treatment outcome categories.
  • The favorable group comprises patients with nodular lymphocytic and well-differentiated lymphocytic subtypes.
  • The rest of the subtypes belong to the unfavorable outcome group.
  • They include four histologic patterns: diffuse poorly differentiated lymphocytic, diffuse histiocytic, diffuse undifferentiated, and nodular histiocytic.
  • Patients with stage I favorable group can be treated with radiation therapy alone, whereas higher stages of the favorable group and all nonfavorable histologic subtypes are treated with a combination of radiation therapy and chemotherapy.

Imaging Findings

CT

  •  NHL involving the masticator space shows nonspecific CT findings.
  • There is a soft tissue mass that obliterates the normal fat planes of the masticator space.
  • It enhances mildly to moderately after contrast injection.
  • This may be associated cervical lymphadenopathy.
  • The bones that make up the zygomatic arch and posterior wall of the maxillary sinus are often expanded and thinned suggesting a more slow-growing and indolent process

MR

  •   MR imaging findings in the masticator space show an intermediate signal mass that involves the masticator space.
  • This tumor diffusely enhances following contrast administration.
  • The tumor may be intermediate to high signal on T2-weighted sequences.  

Imaging Pearls

  The diagnosis of NHL can be suggested in an elderly adult with soft tissue mass in the masticator space that regressively remodels bone.

• Special attention should be given to the mandibular branch of the trigeminal nerve and foramen ovale in all tumors that involve the masticator space.

• Although extranodal disease is common in NHL fewer than 10% of patients have NHL confined to an extranodal site.

  • Therefore, the presence of a masticator space lesion in association with lymphadenopathy should alert one to the possibility of NHL.

 Non-Hodgkin  s Lymphoma

 

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