Gastric and pulmonary lymphoma presenting as a solitary pulmonary nodule
1 Department of Nuclear Medicine, Division of
Medical Imaging, Royal Perth Hospital, Perth, Australia
2 School of Medicine, Notre Dame University
Fremantle Campus, Fremantle, Australia
3 Department of Nuclear Medicine, Princess Margaret Hospital for Children, Subiaco, Australia
4 WA PET/Cyclotron Service, Nedlands, Australia
The common presentations of lymphoma are widespread
lymphadenopathy or development of constitutional symptoms. This paper presents
a case of a patient who presented with a solitary mass detected on chest X-ray
and underwent FDG-PET for further evaluation of this mass. FDG-PET is a
commonly utilised technique to assess solitary nodules as it not only allows
characterisation of the lesion but can also detect nodal and extra-thoracic
disease with greater accuracy than the standard CT. In this case, FDG-PET
demonstrated abnormal activity in the lung nodule and at the gastro-oesophageal
junction. Biopsies confirmed Non-Hodgkin�s Lymphoma at both sites. The value of
FDG-PET in this case was the determination of previous unsuspected disease in
an unusual presentation of lymphoma and as a useful tool for monitoring the
therapeutic effect post chemotherapy. � 2007 Biomedical Imaging and Intervention
Journal. All rights reserved.
Keywords: FDG-PET, Non-Hodgkin�s Lymphoma, solitary pulmonary
A 71-year-old lady had an incidental finding of an opacity
in her left lower lobe on a chest radiograph. Thoracic CT confirmed the presence
of a 1.0 cm solitary pulmonary nodule but did not identify any lymphadenopathy
or evidence of distant metastatic disease.
The patient was referred for an F18 FDG-PET
study (Figure 1) for investigation of the pulmonary nodule . The PET study
confirmed a small retrocardiac focus of increased FDG uptake within the left
lower lobe nodule (thin arrow) suggestive of a malignant process. In addition,
the study demonstrated abnormal increased activity at the gastro-oesophageal
junction (thick arrow). It was proposed that metastasis at this site from a
primary lung malignancy would be unusual and that two malignancies (i.e. lung
and gastric) were possible . Lung metastasis from a gastric neoplasm was
also possible, however, isolated pulmonary metastasis from gastric cancer is
rare. Thus, further investigation was recommended.
The patient underwent upper gastrointestinal endoscopy.
Biopsy of the gastric wall during endoscopy revealed non-Hodgkin�s lymphoma
(NHL). The patient proceeded to thoracotomy for investigation of her lung
lesion to definitively ascertain the nature of this lesion. Pathology again
confirmed lung NHL. Therefore, the patient was treated with systemic
chemotherapy for lymphoma.
A follow-up post therapy FDG-PET study (Figure 2, right) showed
a complete metabolic response to treatment both in the stomach and the left
lung when compared to the initial study (Figure 2, left).
Non-Hodgkin�s lymphoma is a known but relatively rare
cause of solitary pulmonary nodules . Gastrointestinal lymphoma can be
FDG-avid but can be difficult to differentiate from normal stomach activity
. Likewise, it can be difficult to appreciate with anatomical imaging
methods such as CT. In this case, however, the gastric uptake of FDG was focal
and somewhat more intense than is usually seen at the gastro-oesophageal
junction. This led to the suspicion of a pathological process at this site,
which was subsequently confirmed at biopsy. Lymphoma is usually characterised
by nodal involvement on both CT and FDG-PET. Extranodal disease is less common.
The unusualness of this presentation necessitated tissue confirmation both from
the stomach and the lung nodule.
FDG-PET is used throughout the world in the assessment of
solitary pulmonary nodule. It has been shown to have high sensitivity (>95%)
and high specificity (>75%) in determining whether the nodule is benign or
malignant based on high uptake in the lesion . In this case, FDG-PET
confirmed a likely malignant process with prominent activity seen in the small
FDG-PET in this case also showed a total metabolic
response to treatment following appropriate chemotherapy. In the authors'
institution, post-therapy assessment in NHL is one of the most common
indications for FDG-PET. The findings may be of prognostic significance as
total metabolic response has been associated with improved long term outlook in
NHL . FDG-PET has also been shown to be more accurate in assessing response
to therapy in NHL compared with CT . The whole body nature of PET imaging
coupled with the sensitivity related to its assessment of metabolic function
rather than anatomic detail likely contribute to its enhanced accuracy compared
This case thus illustrates the usefulness of FDG-PETas
- in the assessment of the solitary pulmonary nodule
- in the detection of previously occult disease and
- as a sensitive modality for monitoring therapeutic efficacy in lymphoma.
Figure 1 The PET study (Philips Allegro system) reveals a small retrocardiac focus of increased FDG uptake within the left lower lobe nodule (thin arrow) suggestive of a malignant process. In addition, the study demonstrates abnormal increased activity at the gastro-oesophageal junction (thick arrow).
Figure 2 A follow-up FDG-PET study post therapy (left) shows a complete metabolic response to treatment both in the stomach and the left lung when compared to the initial study (right).
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|Received 3 March 2007; received in revised form 7 August
2007, accepted 17 August 2007
Correspondence: Department of Nuclear Medicine, Division of Nuclear Medicine, Royal Perth Hospital, Box X2213 GPO, Perth WA 6001, Australia. E-mail: firstname.lastname@example.org (Nat P. Lenzo).
Please cite as: Thomas EL, Lenzo NP, Troedson R,
Gastric and pulmonary lymphoma presenting as a solitary pulmonary nodule, Biomed Imaging Interv J 2007; 3(4):e51
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