Post-Transplant Lymphoproliferative Disorder

Published on 19/07/2015 by admin

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Last modified 19/07/2015

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 Site of presentation may depend partially on transplanted organ

image Extranodal (80%) > nodal involvement (20%)
• Imaging findings of post-transplant lymphoproliferative disorder parallel those of non-Hodgkin lymphoma (NHL) in immunocompetent patients
• GI tract: Imaging findings are similar to NHL, including mass-like bowel wall thickening, aneurysmal dilatation, ulcerated polyploid mass, or submucosal nodules

image Increased prevalence of ulceration and bowel perforation
• Liver: Most frequently involved abdominal solid organ

image Single or multiple poorly enhancing masses, discrete mass in porta hepatis, or diffuse infiltration of liver
• Spleen: Splenomegaly ± discrete lesions (usually multiple, hypoattenuating, and variable in size)
• Kidney: Most common site in renal transplant recipients

image Heterogeneous mass surrounding hilar vessels, parenchymal masses, or diffuse infiltrative disease
• Nodal disease: Abdominal nodal involvement in only 15-20% of cases

image Nodal involvement much less common than in immunocompetent NHL

TOP DIFFERENTIAL DIAGNOSES

• Recurrent or new malignancy
• Opportunistic infections

PATHOLOGY

• Most cases are related to B-lymphocyte proliferation due to Epstein-Barr virus (EBV) infection

CLINICAL ISSUES

• High mortality, with survival rates of only 25-35%
• Treatment: Reduction or cessation of immunosuppression can be effective, although antiviral drugs, chemotherapy, or rituximab may be necessary
image
(Left) Axial CECT in a patient post liver transplant demonstrates a new hypodense mass image in the porta hepatis, as well as an enlarging portacaval lymph node image.

image
(Right) Axial CECT in the same patient demonstrates extensive retroperitoneal lymphadenopathy image. The findings of post-transplant lymphoproliferative disorder (PTLD) in this case are indistinguishable from traditional non-Hodgkin lymphoma (NHL) in an immunocompetent patient.
image
(Left) Axial NECT demonstrates mass-like wall thickening image of a segment of colon with aneurysmal dilatation.

image
(Right) Coronal NECT in the same patient again demonstrates the significant wall thickening image of the bowel segment with dilatation. This is a common appearance for both NHL in immunocompetent patients and PTLD.

TERMINOLOGY

Abbreviations

• Post-transplant lymphoproliferative disorder (PTLD)

Definitions

• Heterogeneous group of lymphoproliferative diseases that occur in post-transplant setting (either solid organ or stem cell transplants), ranging from abnormal lymphoid hyperplasias to frank malignancies

IMAGING

General Features

• Location

image Extranodal involvement (80%) is much more common than nodal involvement (20%)

– Unlike lymphoma in general population where nodal disease predominates
image Can occur nearly anywhere, with common locations including lungs, GI tract, and CNS

– Site of presentation may depend partially on type of transplanted organ
– Abdominal cavity is most frequently involved (up to 50% of all cases)
– May occur within renal and liver allografts

image Some studies have suggested that PTLD may preferentially affect allograft itself
• Size

image Masses and nodes range from < 1 cm to huge masses

Imaging Recommendations

• Best imaging tool

image CECT for initial diagnosis
image PET/CT for staging and follow-up

CT Findings

• Imaging findings of PTLD mostly parallel those of non-Hodgkin lymphoma (NHL) in immunocompetent patients
• GI tract

image Small bowel (distal > proximal) > colon > stomach > duodenum > esophagus
image Imaging findings are similar to NHL in immunocompetent patients

– Mass-like wall thickening (most common) with aneurysmal dilatation of lumen
– Dominant polyploid mass (often with ulceration) or multiple submucosal nodules
– May present with intussusception
image Unlike lymphoma in general population, there is a markedly increased prevalence of ulceration and perforation of bowel

– Spontaneous perforation may be 1st symptom of PTLD
• Liver

image Most frequently involved abdominal solid organ
image Several possible appearances

– Most often single or multiple low attenuation, poorly enhancing masses

image Lesions may vary in size (few mm to few cm)
– Diffuse or geographic infiltration of liver with no discrete lesions (liver appears steatotic)
– Discrete mass in porta hepatis (sometimes with extension into biliary tree or gallbladder)

image Unique manifestation of PTLD (not common with immunocompetent lymphoma)
• Spleen

image Spleen involved in 10-40% of cases (particularly common after liver transplant)
image Possible appearances

– Splenomegaly (most common) ± discrete parenchymal lesions
– Parenchymal lesions are typically multiple, low-attenuation, and variable in size
image Spontaneous rupture is possible complication
• Kidney

image Most commonly involved site in renal transplant recipients and may affect native kidneys or allograft
image Renal allograft involvement

– Heterogeneous mass surrounding hilar vessels
– Multifocal parenchymal masses
image Native kidney involvement

– Almost always unilateral
– Discrete round, hypoenhancing parenchymal lesions
– Diffuse infiltrative disease with nephromegaly
• Adrenal

image Adrenal involvement in 5%
image Diffuse infiltration with adrenal enlargement or discrete homogeneous hypoenhancing mass
• Pancreas

image 

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