Thoracic Imaging 2003 - Society of Thoracic Radiology

T-cell rich B-cell NHL is a variety in which rare neoplastic
B-cells are present in a background of much larger numbers of
reactive, non-neoplastic T-cells. In the past, it was probably
classified as either a variant form of HD, or as T-cell variety of
NHL. With modern methods for detection of immunoglobulin
gene rearrangements, the rare neoplastic clone of B-cells can
now be more accurately identified.
Mantle cell NHL is an uncommon form of NHL with a relatively
aggressive course. It demonstrates a typical and relatively
specific translocation and may be nodular or diffuse in histologic
growth pattern. It may involve the GI tract in the form of
multiple lymphomatous polyposis, with a tendency to disseminate
widely. This is in contrast to MALT lymphomas of the GI
tract, which are typically indolent and often limited in extent.
Intravascular lymphomatosis is an extremely rare disorder in
which neoplastic cells are found only within vascular structures.
Most often patients present with central nervous system findings,
but occasionally the diagnosis is made in other organs,
such as the kidneys or the lungs. When lung involvement is
present, patients may present with dyspnea or cough and imaging
may show air-trapping or mosaic perfusion.
Treatment effects
In general, lymphomas are rarely treated surgically except in
order to obtain tissue for initial diagnosis. Most treatment regimens
use either chemotherapy, radiation therapy or a combination
of the two. Therefore, it is important to recognize some of
the expected imaging findings of toxicity associated with both
of these treatments. Another important consideration is the incidence
of second primary tumors, particularly after radiation
therapy. Since HD is often seen in young patients, the long
latency period of radiation-induced neoplasia must be kept in
mind. Because chemotherapy is often administered using
indwelling catheters, complications of long-term venous access
must also be considered.
Typical findings of radiation are most often seen in the lungs
on CT imaging. This can range from very subtle signs of volume
loss in the irradiated region to extensive fibrosis and distortion
of lung architecture. The typical imaging features of radiation
fibrosis include bands of linear density, traction bronchiectasis,
retraction and volume loss. Such marked findings are
more common with higher doses of radiation and are also
increased in patients receiving concomitant radiation and
chemotherapy. Local lung function, as measured with ventilation
and perfusion scanning, drops initially after radiation but
then partially recovers at from 3-18 months.
Almost any chemotherapeutic drug can cause a toxic
response, most often in the lungs. Such agents as bleomycin are
well-known for this effect. The agents typically used to treat
lymphoma have a much lower incidence of pulmonary toxicity
than bleomycin, but occasionally can produce similar effects.
The typical imaging features are patchy or ground-glass opacities,
sometime evolving to reticular and fibrotic appearance,
located in the lung periphery often with a basilar predominance.
The most characteristic location on chest film is in the lateral
costophrenic regions. In a patient with new interstitial abnormality
after chemotherapy, a differential diagnostic consideration
must also include edema from cardiac toxicity. Again, cardiac
toxicity is most well-known in response to adriamycin but
can occur with other agents.
Followup regimens
Most oncologists use a standard regimen of imaging in following
patients treated for HD and NHL, but evidence-based
investigations of these regimens are limited. Overall, imaging is
probably overused, since a combination of frequent clinic visits,
thorough physical examinations and lab exams will probably
detect most recurrent disease. Imaging could then be reserved
for solving specific problems. In an investigational setting, obviously
more thorough imaging is usually needed. In the future,
positron emission imaging may simplify followup protocols and
may replace routine followup CT scans in some cases.
Conclusions
Lymphoma is really a group of related diseases that can have
a wide variety of appearances on imaging and can range from
indolent, slow-growing disease to highly aggressive, rapidly
fatal disease. Classification of lymphoma has undergone considerable
change in recent years due to our evolving understanding
of the genetic and cellular mechanisms of the various subtypes.
It is important for radiologists to have an understanding
of current classifications and how they may relate to the expected
appearance of disease on imaging. It is also important for
radiologists to have an appreciation of the expected findings
related to the various treatments of lymphoma.
REFERENCES:
1. Skarin, Shaffer and Wieczork, editors, Atlas of Diagnostic
Oncology, 3rd edition, Mosby (London), 2003.
2. L Kostakoglu and Sj Goldsmith, Positron emission tomography
in lymphoma: comparison with computed tomography and
Gallium-67 single photon emission tomography, Clinical
Lymphoma 1:67-74, 2000.
3. A Elis, D Blickstein, O Klein, et al, Detection of relapse in non-
Hodgkin’s lymphoma: role of routine followup studies. Am J
Hematology 69:41-44, 2002.
4. LJ King, SP Padley, AC Wotherspoon, AG Nicholson.
Pulmonary MALT lymphoma: imaging findings in 24 cases.
European Radiol 10:1932-1938, 2000.
5. JC Theuws, Y Seppenwoolde, SL Kwa, et al. Changes in local
pulmonary injury up to 48 months after irradiation for lymphoma
and breast cancer. Int J Rad Onc, Biol, Physics
15:1201-1208, 2000.
6. GC Ooi, CS Chim, AK Lie, KW Tsang, Computed tomography
features of primary pulmonary non-Hodgkin’s lymphoma. Clin
Radiol 54:438-443, 1999.
7. O Honda, T Johkoh, K Ichikado, et al. Differential diagnosis of
lymphocytic interstitial pneumonia and malignant lymphoma
on high-resolution CT. AJR 173:71-74, 1999.
8. JG Wall, YG Hong, JE Cox, et al. Pulmonary intravascular
lymphomatosis: presentation with dyspnea and air trapping.
Chest 115:1207-1210, 1999.
9. P Porcu, CR Nichols. Evaluation and management of the
“new” lymphoma entities: mantle cell lymphoma, lymphoma of
mucosa-associated lymphoid tissue, anaplastic large0cell lymphoma
and primary mediastinal B-cell lymphoma. Curr Prob
Cancer 22:283-368, 1998.
10. American Cancer Society. Cancer Facts and Figures 2001,
ACR( Atlanta), 2001.
11. R Bar-Shalom, M Mor, N Yefrmov, SJ Goldsmith. The value
of Ga-67 scintigraphy and F-18 fluorodeoxyglucose positron
emission tomography in staging and monitoring the response
of lymphoma to treatment. Sem Nuc Med 31:177-190, 2001.
12. L Bordeleau, NL Berinstein. Molecular diagnostics in follicular
non-Hodgkin’s lymphoma: a review. Sem Oncol 27:42-52,
2000.
13. M Hummel, H Stein, Clinical relevance of immunoglobulin
mutation analysis. Curr Opinion Oncol 12:395-401, 2000.
14. RC Hankin, SV Hunter. Mantle cell lymphoma. Arch Pathol
Lab Med 123:1182-1188, 1999.
15. E Morra. The biological markers of non-Hodgkin’s lymphomas:
their role in diagnosis, prognostic assessment and
therapeutic strategy. Int J Biol Markers 14:149-153, 1999.
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