A 52-year-old male came to the Radiology Department of the Hospital Universitario La Paz, Paseo de La Castellana, Madrid, Spain, to undergo routine chest radiography to screen for any organic cause of obstructive sleep apnoea syndrome (OSAS) or any other medical condition related to this pathology. There was no history of cough, chest pain, dyspnoea, haemoptysis, fever, chills, night sweats, weight loss, occupational exposure or recent travel. He was neither a smoker nor an alcoholic.
On clinical examination, there was no evidence of peripheral lymphadenopathy or hepatosplenomegaly. Laboratory findings were normal.
Serological tests were negative for HIV infection and the Mantoux test was also negative.
The chest radiograph showed two voluminous masses with extraparenchymatous features, in the right upper lobe and in the left major fissure. No pleural effusion was noted (). Then, a chest CT with intravenous iodinated contrast medium was performed and two pleural masses with homogenous attenuation were seen, as demonstrated in the chest radiograph. Neither pleural effusion nor mediastinal enlarged lymph nodes were present. Lung parenchyma appeared normal, without nodules or consolidations (). Initially, a tumour composed of fibrous connective tissue was suspected. In order to rule out a fibroid tumour, the patient underwent MRI. This revealed two homogeneous pleural masses that showed hypointense signal on T1 weighted sequences and were hyperintense on T2 weighted sequences, resulting in the rejection of the fibroma diagnosis (). There was no evidence of signal loss in the fat-suppressed T2 weighted sequences, which indicated a fat component. A CT-guided FNAC of the biggest mass located in the right superior lobe was performed. Two passes were carried out with a 25-G×9 cm needle. A Diff-Quik stain (Dade Behring, Deerfield, IL) of both samples was made immediately () in order to check that there was sufficient and valid material for the cytological diagnosis. Material for ThinPrep (Hologic, Bedford, MA) liquid-based cytology was also separated and immunocytochemistry techniques (CD20 and CD3), Ig H and T-cell receptor (TCR)-γ polymerase chain reaction (PCR) clonal analyses were made. The smears showed a plentiful lymphoid cellularity of polymorphic appearance with predominance of medium-sized lymphocytes with a basophilic cytoplasm just visible at the edge of the cell, intermingled with a small number of bigger cells probably from the germinal centre and isolated histiocytes. A clear predominance of B-cells (CD20+) over a minority of T-cells (CD3+) was observed. Using PCR analysis, monoclonal rearrangement of the fraction Fr3a of the Ig H was identified. With these findings, the diagnosis of non-Hodgkin's lymphoma was made. Finally, the diagnosis of MALT-type lymphoma was made by means of 2 percutaneous samples of CT-guided tru-cut biopsy with a 20-G×15 cm needle and a papanicolaou stain.
Chest X-ray, posteroanterior projection. Note a mass over the right hemithorax with extraparenchymatous features and a second mass over the left major fissure. No pleural effusion is present.
Figure 2 Chest enhanced CT, (a) axial, (b) coronal and (c) sagittal images that show two pleural masses with homogeneous attenuation located in right upper lobule and left major fissure without pleural effusion. (d) Chest MR, coronal T1 weighted sequence demonstrates (more ...)
Diff-Quik stain of a smear obtained from the biggest pleural mass. Abundant lymphoid cell population with polymorphous appearance is shown. Notice the predominance of CD20-positive cell population over a CD3-positive one.