Primary mediastinal large B-cell lymphoma

Case contributed by Dr Bruno Di Muzio

Presentation

Chest pain.

Patient Data

Age: 60 years
Gender: Female
X-ray

Chest

Large right upper lobe mass that is unclear if purely pulmonary or mediastinal. The lungs and pleural spaces are otherwise clear. Mediastinal contours are otherwise normal. No destructive bone lesions. 

Large mass (7.5 cm) in the right paratracheal region appears to extend
from the right hilum. The trachea deviates slightly to the left and the
SVC is partially narrowed in its mid-portion but not obstructed. The upper
lobe bronchus is patent.
Bibasal mild dependent changes in the lungs bilaterally. Small area of linear
atelectasis or scarring in the lingula. A tiny area of peripheral opacity in
the right middle lobe laterally adjacent to the pleura, likely inflammatory.
No pulmonary features of sarcoidosis.
No effusions. No pneumothorax.
Within the mediastinum, subcentimeter nodes are seen in the prevascular
space, but no other mediastinal nodes identified. Vascular structures appear
otherwise unremarkable. Upper abdominal viscera are unremarkable for arterial
phase examination. Multi-level degenerative change in the thoracic spine but
no other significant bony lesion identified.
Conclusion: Right paratracheal mass reaching hilum likely bronchogenic neoplasm but
requires tissue confirmation. Minor associated compression of the SVC but no obstruction. No airway obstruction.

Case Discussion

The differentials raised to this were of primary lung carcinoma or lymphoma. It is difficult to determine if the lesion is mediastinal or pulmonary, but a mediastinal component is certainly present. Further CT abdomen and pelvis was unremarkable, no evidence of disease elsewhere.

CT-guided core-biopsy was performed: 

Microscopy: The biopsies consist of tissue cores showing focally prominent stromal
fibrosis and a heavy lymphoid infiltrate, as well as relatively small
fragments of normal-appearing pulmonary alveolar tissue. The lymphoid
infiltrate has a vaguely nodular architecture and consists of an admixture of
small lymphocytes, histiocytes, eosinophils, and aggregates of larger cells
with slightly irregular nuclear membranes, vesicular chromatin, prominent
nucleoli and pale cytoplasm. Reed Sternberg cells are not seen. Very focally,
the lymphoid cells infiltrate in the wall of small blood vessels. There is no
necrosis and granulomas are not identified.
Immunohistochemistry has been performed and the large cells show positive
immunostaining for CD20, CD79a and CD30. CD3 and CD5 stain large numbers of
admixed T lymphocytes. CD10 is positive in scattered cells. There is no
staining for EBV-LMP. Cytokeratin (AE1/3) stains small nests and tubular
structures of epithelial cell, possibly thymic remnants.
Conclusion:  Right lung, core biopsies- Atypical B lymphocyte proliferation,
consistent with mediastinal (thymic) large B-cell lymphoma.

Further staging with PET/CT showed abnormal FDG uptake confined to a single large area of lymphoma in the right lung/paratracheal location and some small peri-bronchial lesions.

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Case information

rID: 74837
Published: 7th Mar 2020
Last edited: 7th Mar 2020
Inclusion in quiz mode: Included

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